Dissertations / Theses: 'Neuroradiologia'

7

DONISELLI, FABIO MARTINO. "NEW ADVANCES IN QUANTITATIVE RADIOLOGY: RADIOMICS IN NEURORADIOLOGY APPLIED TO PRIMARY BRAIN TUMORS USING A MACHINE LEARNING APPROACH." Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/932853.

Full text

Abstract:

Arterial spin labelling (ASL) radiomics analysis to predict IDH mutation and MGMT methylation status in gliomas Fabio M. Doniselli1,2, Riccardo Pascuzzo1, Eleonora Bruno3, Domenico Aquino1, Mattia Verri, Alberto Redolfi, Valeria Cuccarini1, Marco Moscatelli1,2, Maria Grazia Bruzzone1, Luca Maria Sconfienza2,4 Abstract Objectives: To evaluate the strength and ability of radiomics features extracted from multiple tumor subregions on MR brain images to predict MGMT promoter (MGMT) methylation status and isocitrate dehydrogenase (IDH) mutation in glioma patients through a multiparametric MRI-based radiomics model, using arterial-spin labelling (ASL) perfusion imaging. Methods: Retrospective single-institution study in a cohort of 52 glioma patients. Radiomics-based models with a minimal set of relevant features and clinical parameters were built for MGMT methylation and IDH-mutation prediction from a training cohort (31 patients) and tested on an validation cohort (13 patients). Results: Feature selection methods (Boruta, RFE and LR-EL) identified age and 3 radiomics features for MGMT prediction and 3 features for IDH prediction. For IDH prediction, SVM classifier achieved average 96.8% accuracy and 0.929 AUC during the training phase, and 84.6% accuracy and 0.60 AUC on the test set. For MGMT methylation prediction, SVM classifier achieved average 67.7% accuracy and 0.765 AUC during the training phase, and 38.5% accuracy and 0.429 AUC on the test set. Conclusions: The classification model based on both demographic (age) and radiomic ASL perfusion characteristics had the best performance in predicting the IDH mutational status of gliomas. This result suggests that the proposed method has promising efficacy in predicting IDH mutational status. We have not obtained a sufficient result trying to correlate radiomics with the MGMT mutational pattern. Assessment of quality and classification performances of MRI-based radiomics studies on MGMT methylation in gliomas: a systematic review Fabio M. Doniselli1,2*, Riccardo Pascuzzo1*, Massimiliano Agrò3, Domenico Aquino1, Federica Mazzi1, Francesco Padelli1, Marco Moscatelli1, Maria Grazia Bruzzone1, Luca M. Sconfienza2,4 Objectives To evaluate the quality of MRI-based radiomics studies predicting the O6-methylguanine-DNA methyltransferase (MGMT) methylation status in gliomas, using radiomics quality score (RQS) and Image Biomarkers Standardization Initiative (IBSI) guidelines, and examine their classification performance. Methods PubMed Medline and EMBASE were searched to identify MRI-based radiomics studies on MGMT methylation in gliomas until January 31, 2022. Included studies were scored according to RQS (16 components) and IBSI (six items) scales by two raters. Results We included 20 out of 62 identified studies. The median RQS total score was 32% of the maximum (11.5 out of 36), ranging between 8% and 44%. Eleven studies performed external validation; only three studies performed decision curve analysis to report potential clinical utility. All studies reported area under the curve (AUC) or accuracy, and 14 computed these statistics using resampling methods (e.g., cross-validation). No study performed phantom study, cost-effectiveness analysis, and prospective validation. Regarding IBSI items, 14 studies (70%) performed signal intensity normalization, while few performed N4 bias-field correction (4, 20%) and skull stripping (3, 15%). Good classification performance (AUC>0.75) was obtained by 11 (55%) studies, but only four of them performed external validation (on sets with 20-60 patients). On the contrary, seven out of the nine studies with lower classification results performed external validation (on sets with 27-126 patients). Conclusions Adherence to RQS and IBSI guidelines was generally low. MGMT methylation status appears to be correlated with radiomic features, but with great heterogeneity of results. To confirm this trend, strict implementation of RQS and IBSI criteria is needed. Radiomics for MGMT methylation detection in GBM using conventional pre-operative MRI Fabio M. Doniselli1,2, Riccardo Pascuzzo1, Massimiliano Agrò3, Domenico Aquino1, Elena Anghileri, Bianca Pollo, Valeria Cuccarini1, Marco Moscatelli1, Francesco DiMeco, Maria Grazia Bruzzone1, Luca M. Sconfienza2,4 Abstract Objectives: To evaluate the strength and ability of radiomics features extracted from multiple tumor subregions on MR brain images to predict MGMT promoter (MGMT) methylation status in GBM patients through a multiparametric MRI-based radiomics model. Methods: Retrospective single-institution study in a cohort of 277 GBM patients. Radiomics-based models with a minimal set of relevant features and clinical parameters were built for MGMT methylation prediction from a training cohort (196 patients) and tested on an validation cohort (81 patients). Radiomic Quality Score (RQS) was equal to 15. Results: Feature selection methods (Boruta, RFE and LR-EL) identified age and 218 radiomics features. SVM classifier achieved average 73.6% (standard deviation: 6.5%) accuracy and 0.836 (0.054) AUC during the training phase, and 59.3% (95% confidence interval: 47.8%-70.0%) accuracy and 0.553 (0.412-0.686) AUC on the test set. Conclusions: We agree on the probable presence of subtle association between imaging characteristics and MGMT methylation status. However, further verification on the strength of this association is needed, as the low diagnostic performance in the validation cohort is still not sufficiently robust to allow clinically meaningful predictions.

APA, Harvard, Vancouver, ISO, and other styles

8

MIGNOGNA, Donatella. "Analysis of the role of the neuronal receptor LRP8 in the production of exosomes in a cellular model and in the context of Alheimer's disease." Doctoral thesis, Università degli studi del Molise, 2021. http://hdl.handle.net/11695/100707.

Full text

Abstract:

Un numero crescente di evidenze ha rivelato che alterazioni del sistema endosomiale-lisosomiale sono collegate ad un malfunzionamento nello smistamento di diverse proteine, portando ad una significativa alterazione della stessa omeostasi proteica. Queste alterazioni risultano particolarmente compromettenti nel campo delle malattie neurodegenerative. In questo scenario, gli esosomi, vescicole extracellulari derivate dal sistema endosomiale-lisosomiale, che riflettono le alterazioni presenti nelle cellule che le hanno prodotte, hanno attirato l'attenzione della comunità scientifica, come possibili marcatori precoci di malattia. Nel campo della malattia di Alzheimer, gli esosomi hanno dimostrato la capacità di ridurre la beta-amiloide cerebrale coinvolgendo l'assorbimento microgliale e gli effetti negativi come la diffusione della tau iperfosforilata, quindi potrebbero essere coinvolti nei meccanismi di apoptosi e, in ultima analisi, contribuire alla degenerazione dendritica. L'espressione dell'apolipoproteina E4, il fattore più rilevante nella malattia di Alzheimer ad esordio tardivo, ha un impatto negativo sulla produzione di esosomi, sia negli esosomi derivati dal cervello umano, sia nel modello murino umanizzato che esprime l'allele ApoE4. Uno dei bersagli dell'apolipoproteina E è la proteina 8 correlata al recettore delle lipoproteine a bassa densità (LRP8 o ApoER2), altamente espressa nel tessuto neuronale e attivamente coinvolta nella formazione della memoria e nella modellazione dei dendriti. Considerando che in precedenza abbiamo osservato che la localizzazione e l'elaborazione di LRP8 sono alterate nella corteccia cerebrale di pazienti affetti da Alzheimer sporadico e familiare, abbiamo deciso di analizzare il ruolo dell'LRP8 sulla produzione di esosomi. Abbiamo riscontrato che negli esosomi derivati dal cervello di pazienti affetti da Alzheimer sporadico e familiare (SAD e FAD), sono fortemente presenti frammenti C-terminali del recettore LRP8 con peso molecolare inferiore a 15 kDa, che invece non sono evidenti nei controlli; segno che il processo proteolitico di LRP8 è fortemente alterato in caso di malattia e che il contenuto delle vescicole cambia radicalmente. Anche la produzione di esosomi cambia radicalmente, essendo fortemente compromessa nel caso di FAD. Abbiamo eseguito esperimenti in vitro utilizzando cellule wild-type Neuro 2A, trasfettate stabilmente con il recettore umano LRP8 (hLRP8) (Neuro 2A DDK myc e Neuro 2A LRP8 HA) e abbiamo scoperto che l'espressione del recettore LRP8 aumenta significativamente la produzione di esosomi. Abbiamo anche espresso nelle cellule Neuro 2A wild-type, la proteina umana Amyloid Precursor Protein 695 (hAPP 695), e abbiamo osservato che i frammenti C-terminali LRP8 sono presenti sia nei lisati cellulari che negli esosomi. Abbiamo evidenziato che il trattamento con ApoE4 umano ricombinante e DAPT (un inibitore della γ-secretasi) diminuisce la produzione di esosomi in vitro e che il trattamento con ApoE4 aumenta i frammenti C-terminali di LRP8 negli esosomi. Infine, per confermare che il recettore LRP8 è coinvolto nella produzione di esosomi, abbiamo eseguito un silenziamento sul recettore LRP8 utilizzando le cellule wild-type Neuro 2A. Abbiamo osservato che silenziando l'espressione di LRP8, c'è una significativa riduzione del numero di esosomi prodotti. An increasing number of evidences has revealed that alterations of endosomal–lysosomal system are connected to alterated sorting and trafficking of different proteins, leading to a significant alteration of protein homeostasis itself. These alterations result particularly compromising in the field of neurodegenerative diseases. In this scenario, exosomes, extracellular vesicles derived from endosomal– lysosomal system, reflecting the alterations present in the cells that produced them, have attracted the attention of the scientific community, as possible early markers of disease. In the field of Alzheimer Disease, exosomes have been shown the capacity to reduce brain Amyloid-beta involving microglial uptake, and negative effects as spreading hyperphosphorylated tau, therefore they could be involved in the mechanisms of apoptosis and, ultimately, contribute to dendritic degeneration. Apolipoprotein E4 expression, the most relevant factor in Late Onset Alzheimer Disease, has a negative impact on exosomes production, both in human brain derived exosomes, and in humanized mouse model expressing ApoE4 allele. One of the target of Apolipoprotein E is Low-density lipoprotein Receptor-related Protein 8 (LRP8 or ApoER2), highly expressed in neuronal tissue and actively involved in memory formation and spines dendridic modeling. Considering that we previously observed that LRP8 localization and processing are alterated in the cerebral cortex of sporadic and familial Alzheimer’s Disease patients, we decided to analyze the role LRP8 on exosomes production. We found that in exosomes derived from brain of patients affected by sporadic and familial Alzheimer (SAD and FAD), C-terminal fragments of the LRP8 receptor with molecular weight less than 15 kDa are strongly present, which instead are not evident in controls; a sign that the proteolytic processing of LRP8 is strongly altered in case of disease and that the contents of the vesicles change radically. The production of exosomes also changes radically, being strongly compromised in the case of FAD. We performed in-vitro experiments using Neuro 2A wild-type cells, stably transfected with human LRP8 (hLRP8) receptor (Neuro 2A DDK myc and Neuro 2A LRP8 HA), and we found that LRP8 receptor expression significantly increases exosomes production. We also expressed in Neuro 2A wild-type cells, the human protein Amyloid Precursor Protein 695 (hAPP 695), and we observed that LRP8 C-terminal fragments are present both in the cell lysates and in the exosomes. We also reported that recombinant human ApoE4 and DAPT (a γ-Secretase inihibitor) treatment, decrease exosomes production in-vitro, and that ApoE4 treatment increase LRP8 C-terminal fragments in exosomes. Finally, to confirm that LRP8 receptor is involved in exosomes production, we performed a silencing on the LRP8 receptor using the Neuro 2A wild- type cells. We observed that silencing the expression of LRP8, there is a significant reduction in the number of exosomes produced.

APA, Harvard, Vancouver, ISO, and other styles

9

MELAZZINI, LUCA. "IMAGING BIOMARKERS OF CEREBRAL SMALL VESSEL DISEASE IN ADULTS WITH CONGENITAL HEART DISEASE." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/805883.

Full text

Abstract:

Aim Imaging biomarkers in medical fields other than oncology tend to be confined to research settings. In neuroimaging, biomarkers of cerebral small vessel disease (SVD) have shown promising results for translation into the clinic but need further validation. In this work, we strove for a more clinically-oriented classification of one of the most representative of SVD biomarkers, i.e. white matter hyperintensities (WMHs), on a large cohort of community-dwelling subjects. We also used this classification to better analyse signs of SVD in a selected population of adults with congenital heart disease. Lastly, we evaluated the steps to be taken for achieving standardisation of WMH assessment. Cerebral small vessel disease in adults with tetralogy of Fallot: preliminary results In this section we describe our exploratory research on a small sample of 10 adult patients with surgically corrected tetralogy of Fallot and 10 age- and sex-matched control subjects. Cerebral microbleeds were visible in every patient and in one control subject. Also, a significant correlation between WMH volume and severity of symptoms of heart failure was observed. Even though the aetiology of the observed findings remained obscure, cerebral microbleeds and WMHs may indicate an increased susceptibility to brain microvascular damage in congenital heart disease and have been deemed worthy of further investigations. Imaging biomarkers of small vessel disease in adults with congenital heart disease: a systematic review Considering our preliminary findings, we extensively reviewed the available literature on vascular injury in adults with congenital heart disease. We found few preliminary studies on this topic, all of which carried several methodological limitations. However, all studies reported a variety of brain vascular changes in the examined patients, ranging from signs of SVD to silent stroke and cortical atrophy. The assumption that these findings differ from those visible in children with heart defects needs to be confirmed. For this purpose, neuroimaging studies in adults with congenital heart disease are needed to differentiate past global lesion burden from present chronic ongoing cerebrovascular disease. Automatic sub-classification of white matter hyperintensities: application to a large community-dwelling cohort As WMH total volume is variably associated with cognition, we developed an automatic method to classify them into four categories according to lesion location (periventricular versus deep) and lesion intensity in T1 and T2-weighted sequences. We applied this method on brain scans from 684 older adults from the Whitehall II study. We also showed that periventricular white matter hyperintensities that appear hypointense in T1-weighted images were significantly associated with poorer performance in several cognitive tests in this cohort. Interestingly, we found no association between total WMH volume and cognition. These findings suggest that sub-classifying WMHs according to both location and intensity in T1-weighted images provides added value when studying the clinical correlates of this imaging biomarker. Inconsistency in quantifying and reporting white matter hyperintensities volume: a systematic review We tried to estimate a normative range for WMH volume in healthy ageing using the highest level of evidence. We meta-analysed 2743 healthy subjects’ WMH volume reported from 17 studies. Our results showed an extremely high heterogeneity across the examined studies. We thereby proposed methodological strategies needed to overcome the current inconsistency in WMH assessment, such as harmonisation of image acquisition and standardisation of anatomical definitions. Most importantly, effective communication between researchers and clinicians is strongly warranted to translate technical know-how for imaging biomarkers assessment into clinical practice. The BACH Study In view of our preliminary results and considering the dearth of scientific evidence on the topic of brain involvement in adults with congenital heart disease, we launched the Brain Aging in Congenital Heart disease (BACH) San Donato study. This multidisciplinary study comprises an extensive brain imaging protocol to investigate signs of small vessel disease and a thorough neuropsychological battery to test patients’ cognitive performance. We found that automatically-detected white matter hyperintensities located in the deep white matter were associated with poorer performance at the frontal assessment battery. Also, this study confirmed that patients had a much larger number of cerebral microbleeds than healthy controls. Conclusions In this thesis we showed that cerebral microbleeds are over-expressed in adult patients with congenital heart disease. Longitudinal studies will aid in clarifying the role of this and other biomarkers of SVD in predicting clinical outcomes. Meanwhile, much effort must be put into reaching standardisation of WMH assessment. Optimal characterisation of brain vascular health in congenital heart disease would enable physicians to adopt prompt strategies to prevent the risk of cognitive deterioration in this category of patients. Full translation of research findings into clinical practice would then be achieved.

APA, Harvard, Vancouver, ISO, and other styles

10

Fällmar, David. "Visual assessment of perfusion and metabolism in neurodegenerative dementia." Doctoral thesis, Uppsala universitet, Radiologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-304731.

Full text

Abstract:

A worldwide demographic shift is currently occurring, with rapidly increasing numbers of elderly individuals. Since the incidence of neurodegenerative disease generally increases with age, this entails an increase in dementia prevalence. There are several strong incentives for establishing robust and widely available imaging methods for the early diagnosis of these diseases. Atrophy patterns are evident only late in the disease process, and the distinction from healthy ageing can often be elusive. For early diagnosis, physiologic parameters such as perfusion or metabolism must be assessed. The available modalities all have restricted clinical usefulness. The main aim of this thesis was to advance the clinical usefulness of perfusion and metabolism imaging in patients with neurodegenerative dementia, with a focus on visual assessment. A cohort of patients with neurodegenerative dementia was included, along with an age-matched control group. All subjects underwent MRI, including a pseudocontinuous ASL sequence and FDG-PET. In papers II and III, a subgroup containing both patients and controls underwent a second FDG-PET with reduced dose. In paper IV, the material was combined with a similar cohort from Amsterdam. Paper I showed that spatial smoothing increased the correlation between visually assessed perfusion and metabolism levels as displayed with FDG-PET. However, the distinction between patients and healthy controls was less satisfactory due to false positives. Paper II showed that differences in regional standard uptake value ratios between normal- and low-dose FDG-PET were small and without clinically significant bias. Paper III showed that the diagnostic performance of Z-score maps showing regions of significant deficits in metabolism was highly similar in normal- and low-dose FDG-PET images. Paper IV showed that ASL perfusion-based Z-score maps can be used for diagnostic purposes with high specificity, but inferior sensitivity, compared to FDG-PET. In conclusion, the included studies address aspects of the visual assessment of perfusion and metabolism neuroimaging, with a focus on clinical usefulness in diagnosing neurodegenerative dementia.

APA, Harvard, Vancouver, ISO, and other styles

11

Zonta, Filippo. "Hippocampal volumes in patients with bipolar-schizophrenic spectrum disorders and their unaffected first-degree relatives." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3423015.

Full text

Abstract:

BACKGROUND: schizophrenic and bipolar disorders are complex and disabling psychiatric diseases whose classical nosography and classification are still under challenging debate aiming to overcome the traditional “Kraepelinian Dichotomy”. For the past hundred years most clinical work and research in psychiatry has proceeded under the assumption that schizophrenia and bipolar disorderaredistinctentities with separate underlying disease processes and treatments. In more recent years there has been increasing evidence for phenomenological, biological and genetic overlap between the two disorders (Potash and Bienvenu 2009). Nowadays, the categorical approach to psychiatric nosography is in contrast with the recent neurobiological, neuropsychological and genetic findings in affective and schizophrenic disorders. Further, symptoms and signs constituting bipolar and schizophrenic disorders are continuously, not dichotomously, distributed; there may be no point of “real cleavage” (Phelps et al. 2008). This recognition has led some clinicians and researchers to call for a diagnostic model that, moving to a “dimensional perspective”, formally recognizes a continuous spectrum from schizophrenic to bipolar (and recurrent depressive) disorders. Kelsoe argued that the existing data coming from various fields of research in bipolar and schizophrenic disorders may best fit a model in which different set of genes predispose to overlapping phenotypes in a continuum. Given the apparent overlap of regions of the genome implicated in bipolar disorder with those for schizophrenia (Kelsoe 1999; Berrettini 2000), the data suggest the possibility that a common polygenic background predisposes to both bipolar disorder and schizophrenia, according to the so-called “multiple threshold model” (Kelsoe 2003). As highlighted by Craddock and Owen, the recent findings are compatible with a model of functional psychosis in which susceptibility to a spectrum of clinical phenotypes is under the influence of overlapping sets of genes, which, together with environmental and epigenetic factors, determine an individual’s expression of illness (Craddock and Owen 2005). A lot of interest is focusing on brain structural abnormalities in patients suffering from schizophrenia and bipolar disorder. A huge amount of neuroimaging studies has been published so far, however the literature is heterogeneous and there is still some degree of uncertainty concerning what key regions are involved in the pathogenesis of such disorders. Schizophrenia and Bipolar Disorder have a number of overlapping symptoms and risk factors, but it is not yet clear if the disorders are characterized by similar deviations in brain morphometry or whether any such deviations reflect the impact of shared susceptibility genes on brain structure. To date there is no consensus about whether, and to what extent, gray matter loss in Schizophrenia is mirrored in Bipolar Disorder and what is the effect of medication or other confounding factors. Studies in family members of patients, who share the risk of the disease but not the confounding factors, may help elucidate whether abnormalities in brain structures are shared by both illnesses. AIM OF THE STUDY: to investigate hippocampal gray matter volume differences in a group of patients with bipolar-schizophrenic spectrum disorders, a group of their unaffected first-degree relatives, and a group of healthy control subjects. METHODS: a total of 104 subjects - 36 schizophrenic or schizoaffective (SZ), 27 bipolar (BP), 2 major depression, 8 unaffected relatives (UR), and 31 healthy controls (HC) - underwent 1,5 T MRI scanning, with volumetric T1 3D acquisition protocol, at the Neuroradiology Unit of Conegliano Hospital. We calculate bilateral hippocampal gray matter volume (HV) and total cerebral volume (TCV) in a sample of 31 SZ, 27 BP, 8 UR and 26 HC, with a stereological method using ANALYZE 10.0 software. RESULTS: we found statistically significant reductions in bilateral HV in the BP-SZ patients compared to HC; the direct comparison between patient groups identified statistically significant reduction in the right HV of SZ, but no significant differences for left HV or TCV (however statistical significance was lost after normalization); statistically significant reduction in the left HV and a trend towards statistical significance for right HV in the UR compared to HC (a trend towards statistically significant reduction in bilateral HV persisted after normalization). CONCLUSION: it might be speculated that the alterations of the gray matter volume in the hippocampus highlighted in our study could be interpreted as a possible structural “biological marker” in the schizophrenic-bipolar spectrum. INTRODUZIONE: schizofrenia e disturbo bipolare sono malattie psichiatriche complesse e invalidanti, il cui inquadramento nosografico è oggetto di continuo dibattito nel superamento della classica “dicotomia Kraepeliniana” tra Dementia Praecox e Malattia Maniaco-Depressiva. Negli ultimi cento anni, buona parte della pratica clinica e della ricerca in psichiatria sono state basate sull’assunto che schizofrenia e disturbo bipolare fossero entità categorialmente distinte, separate da distinti meccanismi patologici e trattamenti. In anni più recenti invece, si sono accumulate numerose evidenze a supporto di una parziale sovrapposizione fenomenologica, biologica e genetica tra questi disturbi (Potash e Bienvenu 2009). Attualmente, l’approccio nosografico “categoriale” nei disturbi affettivi e schizofrenici è in contrasto con le più recenti scoperte in ambito neurobiologico, neuropsicologico e genetico. Inoltre è stato evidenziato come, nemmeno dal punto di vista clinico vi sia un reale punto di “separazione” tra i due disturbi, che presentano segni e sintomi comuni e sovrapponibili (Phelps et al. 2008). Tale consapevolezza ha portato clinici e ricercatori a orientarsi verso un modello diagnostico che, spostandosi in una prospettiva “dimensionale”, formalmente riconosce l’esistenza di uno spettro tra disturbi schizofrenici e bipolari. Kelsoe afferma che i dati provenienti dai vari filoni di ricerca nei disturbi bipolari e schizofrenici potrebbero essere meglio spiegati da un modello in cui differenti set di geni predispongono a fenotipi clinici che si sovrappongono in un continuum. Data la documentata sovrapposizione fra regioni genomiche implicate nel disturbo bipolare con quelle della schizofrenia (Kelsoe 1999; Berrettini 2000), le evidenze suggeriscono la possibilità che un substrato poligenico comune possa conferire una predisposizione a entrambi i disturbi, secondo il cosiddetto modello delle “soglie multiple” (Kelsoe 2003). Come sottolineato da Craddock e Owen, le più recenti scoperte in tale ambito sono compatibili con un modello di psicosi funzionale, nel quale la suscettibilità ad uno spettro di fenotipi clinici è sotto l’influenza di un set di geni condivisi, che, insieme a fattori ambientali ed epigenetici, determina l’espressione di malattia in ciascun individuo (Craddock e Owen 2005). Notevole interesse si sta inoltre focalizzando sulle alterazioni strutturali cerebrali in pazienti affetti da schizofrenia e disturbo bipolare. Nonostante l’ingente mole di studi di neuroimaging finora pubblicati, la letteratura sull’argomento è molto eterogenea ed esiste ancora notevole incertezza su quali siano le specifiche regioni cerebrali coinvolte nella patogenesi di tali disturbi. Schizofrenia e Disturbo Bipolare condividono una serie di sintomi e fattori di rischio, ma non è ancora stato chiarito se questi disturbi siano caratterizzati da comuni modificazioni morfometriche cerebrali e se tali alterazioni riflettano l’impatto di geni comuni di suscettibilità sulla morfologia del cervello. Ad oggi, non è stato definitivamente chiarito se, e fino a che punto, la documentata perdita di sostanza grigia nella Schizofrenia si rifletta anche nel Disturbo Bipolare e su quali siano gli effetti della farmacoterapia o di altri fattori di confondimento. Gli studi sui membri non affetti di pazienti schizofrenici e bipolari, che condividono la predisposizione genetica ai disturbi, ma non i fattori di confondimento, posso rivelarsi utili nel verificare se le varie anomalie cerebrali siano condivise nelle due patologie. SCOPO DELLO STUDIO: analizzare eventuali differenze volumetriche nella sostanza grigia ippocampale in un gruppo di pazienti dello spettro bipolare-schizofrenico, un gruppo di familiari di primo grado non affetti e un gruppo di soggetti sani di controllo. MATERIALI E METODI: un totale di 104 sogetti - 36 pazienti con disturbo schizofrenico o schizoaffettivo (SZ), 27 pazienti con disturbo bipolare (BP), 2 pazienti affetti da depressione maggiore ricorrente, 8 familiari di primo grado non affetti (UR) e 31 controlli sani (HC) sono stati sottoposti ad una procedura di Risonanza Magnetica cerebrale ad 1,5 Tesla, secondo un protocollo di acquisizione di sequenze T1 3D volumetriche, presso l’Unità Operativa di Neuroradiologia del Presidio Ospedaliero di Conegliano. Mediante l’utilizzo del Software ANALYZE 10.0, sono stati calcolati, con un metodo stereologico, i volumi bilaterali della sostanza grigia ippocampale (HV) ed il volume cerebrale totale (TCV) in un campione di 31 SZ, 27 BP, 8 UR e 26 HC. RISULTATI: sono state riscontrate riduzioni volumetriche statisticamente significative della sostanza grigia di ippocampo destro e sinistro tra i gruppi di pazienti dello spettro bipolare-schizofrenico rispetto ai controlli; nel confronto diretto tra il gruppo di pazienti schizofrenici e quello dei bipolari è stata identificata una riduzione statisticamente significativa del volume della sostanza grigia dell’ippocampo destro (tale significatività non persiste in seguito a normalizzazione) e nessuna significativa differenza nei volumi della sostanza grigia dell’ippocampo sinistro o nel volume cerebrale totale; nel confronto tra il gruppo di familiari di primo grado non affetti rispetto al gruppo di soggetti sani di controllo è stata evidenziata una significativa riduzione volumetrica della sostanza grigia dell’ippocampo sinistro e un trend verso la significatività statistica per l’ippocampo destro (tali riduzioni volumetriche della grigia ippocampale mantenevano bilateralmente tale trend verso la significatività statistica anche dopo la normalizzazione). CONCLUSIONE: la alterazione volumetrica della sostanza grigia ippocampale evidenziata nel nostro studio potrebbe essere interpretata come un possibile “marker biologico” strutturale nei disturbi dello spettro schizofrenico-bipolare.

APA, Harvard, Vancouver, ISO, and other styles

12

CAPASSO, Raffaella. "Qualitative versus automatic evaluation of CT perfusion parameters in acute posterior circulation ischemic stroke." Doctoral thesis, Università degli studi del Molise, 2020. http://hdl.handle.net/11695/99046.

Full text

Abstract:

SCOPO Confrontare la performance diagnostica della valutazione qualitativa e quella automatica quantitativa delle immagini TC-perfusione nell’identificazione di core ischemico e penombra ischemica in pazienti con stroke ischemico acuto del circolo posteriore. MATERIALI E METODI Sono stati consecutivamente inclusi nello studio pazienti colpiti da ictus ischemico acuto in territorio di circolo posteriore sottoposti in regime di urgenza a protocollo multimodale TC (GE “Lightspeed” a 64 strati) includendo lo studio di perfusione, dal mese di gennaio 2016 al mese di dicembre 2018. Secondo necessità clinica, alcuni pazienti sono stati studiati al tempo 0 anche con RM (Philips “Intera” 3,0T o “Ingenia” 1,5T) mediante sequenze DWI e FLAIR, mentre altri sono stati sottoposti ad esame RM in un secondo momento. Per determinare l’estensione della lesione ischemica è stato utilizzato il punteggio Posterior circulation - Acute Stroke Prognosis Early CT Score (pc-ASPECT score) applicato nella la valutazione semiquantitativa delle immagini TC basali e nelle mappe perfusionali mediante software CTP-4 (tempo di transito medio, MTT; volume ematico cerebrale, CBV; flusso ematico cerebrale, CBF) al tempo 0, delle sequenze DWI delle RM eseguite al tempo 0 o al controllo, e delle TC basali eseguite di controllo. Le acquisizioni TC perfusionali sono state, inoltre, rielaborate anche mediante il software RAPID (iSchemia View) ottenendo in modo automatico mappe perfusionali colorimetriche e quantitative, includendo anche il parametro tempo al picco massimo (Tmax). RISULTATI Sono stati inclusi 50 pazienti (34 maschi e 16 femmine) con età media di 71,9 anni, tutti sottoposti a protocollo TC multimodale (TC basale + angio-TC + TC perfusione) in acuto (< 24 ore dall’esordio dei sintomi); di questi, 28 pazienti sono stati anche sottoposti a studio RM, entro 8 ore dall’esordio nella metà dei casi. Dei 50 pazienti inclusi, 6 non hanno mostrato core ischemico al follow-up né alterazione di almeno due parametri di perfusione e sono stati considerati come controlli negativi. La valutazione qualitativa dei parametri MTT-CTP4D e Tmax-RAPID nelle mappe colorimetriche ha mostrato la più alta sensibilità (SE) (MTT: 88,6%, p<0,05; Tmax: 90,9%, p<0,05) con sovrapponibile accuratezza (ACC) (88%> 84%, p>0,05) tra i due software. La valutazione qualitativa della TC basale e quella del parametro CBF nella mappa di mismatch RAPID hanno presentato i più bassi valori di SE (29,6% e 6,8% p<0,05) e ACC (38% e 18% p<0,05). La valutazione automatica quantitativa del parametro CBF nelle mappe di mismatch RAPID si è rivelata inferiore in termini di SE (6,8%) rispetto a quella qualitativa delle mappe ottenute con i software CTP4 e RAPID (81,8% e 61,4%), entrambe con equiparabile SE (81,8% > 61,4%, p>0,05). La valutazione automatica quantitativa del parametro Tmax nelle mappe di mismatch RAPID ha presentato ridotte SE e ACC (90,9%>65,9% e 88%>70%) rispetto a quella qualitativa delle mappe colorimetriche RAPID. Non è stata riscontrata significativa differenza tra i punteggi pc-ASPECT assegnati mediante valutazione delle mappe colorimetriche MTT e Tmax né tra quelli attribuiti nelle mappe CBV CTP4D and CBF-RAPID. CONCLUSIONE Indipendentemente dal software utilizzato, la valutazione qualitativa delle mappe colorimetriche ha mostrato maggiore SE rispetto all’analisi automatica quantitativa ed i parametri perfusionali MTT e Tmax sono risultati i più sensibili. Le mappe di mismatch elaborate automaticamente da RAPID non hanno identificato o hanno sottostimato il danno ischemico nella maggior parte dei pazienti, specialmente a carico del talamo e del tronco encefalico. L’attribuzione dei punteggi pc-ASPECT nelle mappe colorimetriche ha mostrato sostanziale equivalenza dei modelli di mismatch MTT-CBV and Tmax-CBF. AIM To examine and compare the diagnostic performance in the detection of acute posterior circulation strokes between qualitative evaluation of software-generated colour maps and automatic assessment of CT perfusion (CTP) parameters by RAPID. METHODS AND MATERIALS Imaging data were retrospectively collected from a prospective database of consecutive patients undergone to multimodal CT scan dataset (GE “Lightspeed” a 64 slices) including CTP performed on admission (<24h after symptom onset) between January 2016 and December 2018. Follow-up imaging consisted in non-contrast CT (NCCT). If clinically indicated, MRI (Philips Intera 3.0 T or Philips Achieva Ingenia 1.5T) was performed either soon after the CTP at the admission or later as follow-up control including DWI and FLAIR sequences. The Posterior circulation - Acute Stroke Prognosis Early CT Score (pc-ASPECT score) was used for quantifying the extent of ischaemic areas on initial NCCT and color-coded maps generated by CTP4 software ( cerebral blood flow, CBF; cerebral blood volume, CBV; mean transit time, MTT). Final pc-ASPECTS was calculated on follow-up NCCT and/or on MRI if performed. Afterwards, CTP data were also processed by RAPID software (iSchemia View) obtaining color-coded maps, including time-to maximum (Tmax), and automatic quantitative mismatch maps. RESULTS A total of 50 patients met the inclusion criteria. 6 out of the 50 patients did not show ischemic core at follow-up imaging neither alteration of at least two perfusion parameters in the same location and were grouped as negative controls. All patients underwent to follow-up NCCT and 28 of them also underwent DWI-MRI. Out of the 28 patients undergone MRI, 14 patients (50%) underwent DWI study within 8 hours after multimodal CT study at admission. The sensitivity (SE) of qualitative evaluation of color-coded MTT-CTP4D map and color-coded Tmax-RAPID map resulted significantly higher than the other ones (MTT: 88.6%, p<0.05; Tmax: 90.9%, p<0.05) with comparable diagnostic accuracy (ACC) (88%> 84%, p>0.05). NCCT at baseline and CBF provided by RAPID quantitative perfusion mismatch maps had the lowest SE (29.6% and 6.8% p<0.05, respectively) and ACC (38% and 18% p<0.05, respectively). CBF assessment provided by quantitative RAPID perfusion mismatch maps showed significant lowest SE (6.8%) in comparison to qualitative evaluations of both color-coded CBF-CTP4D and CBF-RAPID maps (81.8% and 61.4% respectively); no significant SE difference was found between qualitative evaluations of color-coded CBF-CTP4D and CBF-RAPID maps (81.8% > 61.4%, p>0.05).Qualitative evaluation of color-coded Tmax -RAPID maps showed significant higher SE and ACC than quantitative assessment of Tmax automatically provided by RAPID perfusion mismatch maps (90.9%>65.9% and 88%>70%, respectively). No significant differences were found between the pc-ASPECT scores assessed on color-coded MTT and Tmax maps neither between the scores assessed on color-coded CBV-CTP4D and CBF-RAPID maps. CONCLUSION Independently to the software employed, qualitative analysis of color-coded maps resulted more sensitive in the detection of ischemic changes than automatic quantitative analysis. The most sensitive perfusion parameters were MTT and Tmax. RAPID software generated mismatch maps overlooked and underestimated the extent of the ischemic core in the major part of the patients as compared with the qualitative analysis. The limits of identification of the lesions by automatic quantitative mismatch maps mainly lied in the thalamus and brainstem. Visual assessment of CTP pc-ASPECTS on color-coded perfusion maps revealed equivalence of both mismatch models (MTT-CBV and Tmax-CBF) commonly applied in acute setting with implications for treatment decision-making.

APA, Harvard, Vancouver, ISO, and other styles

13

Vendrell, Jean-François. "Neuroradiologie Interventionnelle : expérience clinico-radiologique et intérêt de la détection des cellules endothéliales circulantes." Thesis, Montpellier 1, 2013. http://www.theses.fr/2013MON1T004/document.

Full text

Abstract:

La neuroradiologie Interventionnelle est devenue une spécialité médicale à part entière en évolution permanente avec l'amélioration des technologies radiologiques et endovasculaires. Néanmoins, de trop nombreuses complications liées à la technique elle-même sont encore rapportées. Basés sur notre expérience clinico-radiologique, nous nous sommes plus particulièrement intéressés aux complications thromboemboliques grâce à de nouvelles technologies biologiques permettant d'envisager une analyse des lésions vasculaires à l'échelle cellulaire (Cellsearch®). Ainsi au cours de différents examens diagnostiques et thérapeutiques nous avons analysé les taux artériels et veineux de cellules endothéliales circulantes à différents temps de la procédure. Nous avons démontré l'agression du matériel endovasculaire sur les parois artérielles induisant un relargage immédiat de CECs unitaires et en amas de taille variable, parfois géants (300 µm). Les amas présentant une taille supérieure aux diamètres des microcapillaires ne peuvent pas migrer dans le compartiment veineux et sont donc potentiellement à l'origine d'une occlusion artérielle très distale responsable de lésions microischémiques qualifiées de silencieuses car asymptomatique dans l'ensemble des cas observés. Les lésions pariétales artérielles induites sont ensuite probablement réparées par un mécanisme dynamique mettant en jeu une augmentation lente et progressive des CEPs jusqu'à l'obtention d'une réparation de l'endothélium. Au delà des facteurs mécaniques endovasculaires, l'analyse cellulaire de cette cinétique destruction-régénération des parois artérielles pourrait s'avérer intéressante dans l'évaluation de l'endothélialisation des endoprothèses intracrâniennes Permanents Improvements in radiological and endovascular devices made the Interventional Neuroradiology considered as a complete medical specialty. However, too many procedural complications due to the devices remain observed in all reported series. On the basis of our clinical center experience we decided to analyze thromboembolic complications by using new biological tests allowing to the detection of circulating endothelial cells. During cerebral diagnostic or therapeutic angiography, arterial and venous CECs rates were analyzed before, during, and after endovascular procedures. Thus, we demonstrated the potential arterial wall injury following catheterization that induced unit and cluster of CECs, some of them were giants (300 µm). Clusters presenting with a size up than those described from microcapillary lumen cannot go through venous compartment, and potentially block into a distal artery inducing microischemic stroke (silent embolism) as observed in this work. In addition, the induced arterial wall injury is probably regenerated by a dynamic mechanism involving a delayed increase of CEPs rates, until the new endothelialization. Over endovascular mechanism factor analysis, the CECs-CEPs investigations could be an interesting strategy in the monitoring of intracranial endoprothesis endothelialization

APA, Harvard, Vancouver, ISO, and other styles

14

PIAGGIO, NICCOLO'. "MICROSTRUCTURAL WHITE MATTER PROPERTIES IN MULTIPLE SCLEROSIS: ANATOMICAL SPATIAL MAPPING VIA NODDI MODELLING TO BETTER UNDERSTAND THE MECHANISM OF INJURY." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1046511.

Full text

Abstract:

Introduction. Plenty of literature focused on the topography of multiple sclerosis (MS) injury localization within brain. Various theories were proposed to explain this pattern, calling into question two main hypothesis: 1- preexistent tissue-intrinsic microstructural susceptibility factors 2- cerebrospinal-fluid (CSF)-borne soluble inflammatory factors diffusing through the brain surfaces (inner-ependymal-ventricular and outer-pial-cortical), thence affecting the parenchyma with a decreasing distribution along a distance-from-CSF gradient. However, despite more than one hundred years of efforts, the etio-physio-pathological basis of the onset and development of the MS plaque has not been completely unveiled yet. Recent technological advances in magnetic resonance imaging (MRI) and data post-processing, enabling an in-vivo definition of the local microstructure of the white matter (WM), give new perspectives for untangling the secrets of this complex disease. Materials & Methods. With a novel algorithm to analyze diffusion weighted MRI images, “NODDI”, we created detailed atlases of the microstructural characteristics of the normal WM in a healthy population; parallelly, we defined the topography of the lesions for a MS-affected population. By superposition of the patients lesion maps onto the healthy atlas, we could then test if any of the microstructural NODDI parameters is predictive of development of a T1-visible lesion. We then tested at which deepness of the gradient of distance from CSF, the a-priori microstructural susceptibility factor was more responsible of the T1-visible lesion development. Finally, we computed the mean distance from the CSF of the T1-lesioned tissue, compared to the T1-spared one. Results. In the corresponding areas where the patients developed T1-visible lesions, we found significant higher values of Neurite Density (ND) on the healthy population atlas, if compared to the areas where no lesion was visible on T1 imaging. The a-priori tissue property of high ND was found to have its greatest influence on T1-visible lesion formation especially in the deep WM layer (the furthest from the pial and ventricular surfaces). The NODDI microstructural parameter Orientation Dispersion Index (ODI) showed to have no influence at any level on the tissue proneness to develop a T1-visible lesion. The average distance of the T1-lesioned tissue from the ventricles was higher than the one of the T1-spared tissue. Conclusion. Our results suggest that an higher density of neurites seem to play a role on the probability of development of a T1-visible WM lesion in MS, while the orientation dispersion of the axons does not appear to have any impact on these pathological events. An higher coherence and compactness of structure in the myelin-rich WM areas could constitute a facilitating factor for the auto-inflammatory immune process against myelin antigens. It is interesting to see that this effect, which appears already significant when considered the whole brain, looks to be even more prominent in the “deep WM layer”, which is the furthest-from-CSF part of WM. Conversely, the lesion-promoting effect of high ND seems to be attenuated or neutralized in the WM layers neighboring the CSF: this fact brings to speculate the existence of some underlying interaction between inflammatory soluble factors and tissue structure, at different WM deepness levels.

APA, Harvard, Vancouver, ISO, and other styles

15

Gorges, Sébastien. "Vers un système de navigation 3D en neuroradiologie interventionnelle." Phd thesis, Université Henri Poincaré - Nancy I, 2007. http://tel.archives-ouvertes.fr/tel-00165960.

Full text

Abstract:

En neuroradiologie interventionnelle, la machine d'angiographie RX est le moyen d'imagerie par excellence pour guider le médecin dans l'accomplissement de son geste thérapeutique. Cette machine permet l'acquisition d'une image 3D montrant les artères du patient (ou 3DXA). Cependant, le contrôle visuel du déploiement des outils (guide, cathéter...) est effectué en 2D avec une image temps réel (ou fluoroscopie). Cette thèse a pour ambition de contribuer à l'amélioration des techniqu es de guidage en proposant des outils permettant une utilisation de l?image 3D durant le traitement. Les images étant acquises avec la même machine d'angiographie, nous avons consacré une partie de notre travail au développement de méthodes fiables de calibrage de la chaîne image portée par l'arceau rotatif de la machine. Le but était de comprendre si l'arceau se déformait ou non sous l'influence de son poids. Tirant parti du fait que les images sont acquises avec la même machine, nous avons ensuite proposé une méthode de recalage 3D2D entre l'image 3DXA et la fluorosc opie. Cette méthode exploite les capteurs de position du système et incorpore les déformations subies par le système. Suite à ces travaux, un système permettant la fusion de l'image 3DXA avec la fluoroscopie a été développé en collaboration avec GE Healthcare et évalué au CHU de Nanc y pour le traitement des anévrismes cérébraux. Enfin, un nouveau système doté de deux chaînes images (ou système bi-plan) a été installé à Nancy durant notre thèse. Après avoir développé une méthode de détection 2D du g uide dans les images fluoroscopiques, nous avons initié une première étude de la reconstruction 3D du guide à partir des images bi-plan.

APA, Harvard, Vancouver, ISO, and other styles

16

Smith-Walker, Lisa Ann. "Neuroradiological correlates of neuropsychological functioning in multiple sclerosis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0018/NQ52414.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Lundberg, Staffan. "Rolandic Epilepsy : A Neuroradiological, Neuropsychological and Oromotor Study." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4133.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Higley, Meghan. "Three Cases in Pediatric Neuroradiology: Athabascan Brainstem Dysgenesis Syndrome, Aicardi Goutières Syndrome, and Aplasia of the Parotid Glands." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/221245.

Full text

Abstract:

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. Summary: The human HOXA1 mutation syndromes commonly present with abnormalities of the inner ear and internal carotid arteries. Previous cases describe varying degrees of hypoplasia or aplasia of the affected structures, often with asymmetrical involvement. We present imaging findings documenting complete absence of the internal carotid arteries bilaterally with bilateral Michel aplasia of the inner ear, which, to our knowledge, has not been previously reported. Based on the number of cases identified and birth rates within studied populations, we estimated the incidence of ABDS at 0.5-1:1000 live births on the White River Apache Reservation and 1:3000 live births in the Navajo population. If accurate, this suggests a carrier frequency similar to that for cystic fibrosis in Caucasian populations. ABDS may represent a significantly underrecognized disorder among Athabaskan Native Americans, raising questions of the possible benefit of genetic counseling for affected families. However, cultural considerations in this population bring into question the possible conflict between counseling based on gene theory and traditional beliefs.

APA, Harvard, Vancouver, ISO, and other styles

19

Petrick, Manfred. "ZNS-Störungen bei myotoner Dystrophie Untersuchungen zu Okulomotorik, Neuroradiologie und Neuropathologie /." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96384153X.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Rooksby, J. "A story model of report and work in neuroradiology." Thesis, Lancaster University, 2002. http://eprints.lancs.ac.uk/12193/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Sampedro, Santaló Frederic. "Automatic image quantification strategies in clinical nuclear medicine and neuroradiology." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/402270.

Full text

Abstract:

Amb la revolució de la tecnologia digital d’obtenció d’imatges radiològiques i l’increment de la potència computacional, el camp de la quantificació d’imatges mèdiques ha sorgit. El fet de poder programar un ordinador per a que detecti patrons d’interès en imatges radiològiques i pugui derivar-ne d’aquests indicadors numèrics amb valor clínic fa que, sens dubte, aquest àmbit de coneixement tingui un gran potencial en entorns mèdics i de recerca. En aquesta tesi es presenten un conjunt de contribucions científiques en aquest context. En particular, es descriu el disseny i la implementació d’una sèrie d’estratègies computacionals de quantificació d’imatges de medicina nuclear i neuroradiologia. A continuació es detalla com aquestes tècniques han demostrat ser d’utilitat per a l’estudi de malalties molt rellevants en l’actualitat com són el càncer de mama, el limfoma no-Hodgkin, la pielonefritis, la malaltia d’Alzheimer, la malaltia de Parkinson i l’abús de cànnabis. Con la revolución de la tecnología digital de obtención de imágenes radiológicas y el aumento de la potencia computacional, el campo de la cuantificación de imágenes médicas ha emergido. El hecho de poder programar un ordenador para que detecte patrones de interés en imágenes radiológicas y pueda derivar de ellos una serie de indicadores numéricos con valor clínico hace que, sin duda, este ámbito de conocimiento tenga un gran potencial en el entorno médico y de investigación. En esta tesis se presentan un conjunto de contribuciones científicas en este contexto. En particular, se describe el diseño y la implementación de una serie de estrategias computacionales de cuantificación de imágenes de medicina nuclear y neuroradiología. A continuación se detalla cómo estas técnicas han demostrado ser de utilidad en el estudio de patologias muy relevantes en la actualidad como son el cáncer de mama, el linfoma no-Hodgkin, la pielonefritis, la enfermedad de Alzheimer, la enfermedad de Parkinson i el abuso de cánnabis. With the revolution of digital medical imaging and the increasing computational power, the field of quantitative medical image analysis emerged. By programming a computer to detect patterns of interest in medical images and derive clinically meaningful numerical indicators from them, this field shows promising potential for healthcare and medical research systems. In this thesis, the design and implementation of computer-based quantification techniques in nuclear medicine and neuroradiological images led to several contributions in this field. These image-derived indicators contributed to complement the visual diagnosis and to further understand the pathophysiology of important health issues such as breast cancer, non-Hodgkin lymphoma, pyelonephritis, Alzheimer’s disease, Parkinson’s disease and cannabis abuse.

APA, Harvard, Vancouver, ISO, and other styles

22

Kamran, Mudassar. "Applications of novel imaging protocols and devices in interventional neuroradiology." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:ccb2550c-cb28-42f1-bd95-4dcee4ec1ff4.

Full text

Abstract:

The historical development, current practice, and the future of interventional neuroradiology are intricately linked to the advancements in the imaging and devices used for neuroendovascular treatments. This thesis explores the advanced imaging potential of the C-arm imaging systems used in the neurointerventional suite and investigates the initial clinical experience with a new flow diverter device to treat the intracranial aneurysms. A cohort of aneurysmal SAH patients who developed delayed cerebral ischaemia (DCI) were prospectively studied with a new parenchymal blood volume (PBV) research protocol C-arm CT examination concurrent with a magnetic resonance (MR) imaging examination that included perfusion and diffusion weighted sequences. Using a robust quantitative volume-of-interest analysis, it was demonstrated that C-arm CT PBV measurements are in agreement with MR-PWI CBV and CBF, and the PBV represents a composite perfusion parameter with both blood-flow (≈60&percnt;) and blood-volume (≈40&percnt;) weightings. Subsequently, using a voxel-wise ROC curve analysis and MR-DWI, it was shown that using optimal thresholds, C-arm CT PBV measurements allow reliable demarcation of the irreversibly infarcted parenchyma. For evaluation of ischaemic parenchyma, the PBV measurements were reliable for moderate-to-severe ischaemia but were prone to underestimate the mild-to-moderate ischaemia. A catalogue of reference mean PBV measurements was then created for various anatomical regions encompassing the whole brain after excluding any locations with ongoing ischaemia or infarction. Next, using an ROI-based analysis of the C-arm CT projection data, steady-state contrast concentration assumption underlying the PBV calculations was investigated. It was demonstrated that for clinical scans, the ideal steady-state assumption is not fully met, however, for a large majority of C-arm CT examinations the temporal characteristics of TDCs closely approximate the expected ideal steady-state. The degree to which the TDC of a C-arm CT scan approximates the ideal steady-state was found to influence the resulting PBV measurements and their agreement to MR-CBV. Moreover, the temporal characteristics of TDCs showed inter-subject variation. Finally, the C-arm CT cross-sectional soft tissue images were demonstrated to be of adequate quality for the assessment of ventricles and for the detection of procedural vessel rupture. These findings advance the understanding of the nature of PBV parameter, establish the optimal PBV thresholds for infarction, provide reference PBV measurements, and highlight the limitations of C-arm CT PBV imaging. The work is of considerable clinical significance and has implications for implementation of C-arm CT PBV imaging in the interventional suite for management of patients with acute brain ischaemia. In regards to the initial clinical experience with the flow diversion treatment of intracranial aneurysms, the procedural, angiographic, and clinical outcomes were studied. Several pertinent technical and clinical issues were highlighted for this new treatment approach. Based on the observations made during this work, a new grading schema was then developed to monitor the angiographic outcomes after flow diversion treatment. Using the angiographic data for patients treated with FD, the new grading schema was demonstrated to be sufficiently sensitive to register gradual aneurysm occlusion and evaluate parent artery patency, with an excellent inter-rater reliability and applicability to various aneurysm morphologies. This work (largest multi-centre series at the time of its publication) informed the interventional neuroradiology community about the safety, efficacy, and outcomes of flow diversion treatment. Additionally, it provided a sensitive and reliable scale to evaluate the angiographic outcomes after flow diversion treatment, in both research and clinical practice.

APA, Harvard, Vancouver, ISO, and other styles

23

Naldi, Ilaria <1977&gt. "Studio neuroradiologico (morfologico e funzionale) nei pazienti con Epilessia Frontale Notturna." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5975/1/naldi_ilaria_tesi.pdf.

Full text

Abstract:

L'epilessia frontale notturna (EFN) è caratterizzata da crisi motorie che insorgono durante il sonno. Scopo del progetto è studiare le cause fisiopatologiche e morfo-funzionali che sottendono ai fenomeni motori nei pazienti con EFN e identificare alterazioni strutturali e/o metaboliche mediante tecniche avanzate di Risonanza Magnetica (RM). Abbiamo raccolto una casistica di pazienti con EFN afferenti al Centro Epilessia e dei Disturbi del Sonno del Dipartimento di Scienze Neurologiche, Università di Bologna. Ad ogni paziente è stato associato un controllo sano di età (± 5 anni) e sesso corrispondente. Tutti sono stati studiati mediante tecniche avanzate di RM comprendenti Spettroscopia del protone (1H-MRS), Tensore di diffusione ed imaging 3D ad alta risoluzione per analisi morfometriche. In particolare, la 1H-MRS è stata effettuata su due volumi di interesse localizzati nei talami e nel giro del cingolo anteriore. Sono stati inclusi nell’analisi finale 19 pazienti (7 M), età media 34 anni (range 19-50) e 14 controlli (6 M) età media 30 anni (range 19-40). A livello del cingolo anteriore il rapporto della concentrazione di N-Acetil-Aspartato rispetto alla Creatina (NAA/Cr) è risultato significativamente ridotto nei pazienti rispetto ai controlli (p=0,021). Relativamente all’analisi di correlazione, l'analisi tramite modelli di regressione multipla ha evidenziato che il rapporto NAA/Cr nel cingolo anteriore nei pazienti correlava con la frequenza delle crisi (p=0,048), essendo minore nei pazienti con crisi plurisettimanali/plurigiornaliere. Per interpretare il dato ottenuto è possibile solo fare delle ipotesi. L’NAA è un marker di integrità, densità e funzionalità neuronale. E’ possibile che alla base della EFN ci siano alterazioni metaboliche tessutali in precise strutture come il giro del cingolo anteriore. Questo apre nuove possibilità sull’utilizzo di strumenti di indagine basati sull’analisi di biosegnali, per caratterizzare aree coinvolte nella genesi della EFN ancora largamente sconosciute e chiarire ulteriormente l’eziologia di questo tipo di epilessia. Nocturnal frontal lobe epilepsy (NFLE) is characterized by motor seizuresoccurring during sleep. Aims of the study were to identify the pathophysiological and anatomo-functional factors implicated in the genesis of the motor episodes and possible structural alterations and/or metabolic disorders ,in NFLE patients using advanced techniques of Magnetic Resonance (MR). We have collected a series of patients with NFLE attending the Epilepsy and Sleep Centres of the Department of Neurological Sciences, Bologna University. For each NFLE patient, one control subject of the same sex and age (±5 years) was recruited. All subjects were studied using proton spectroscopy (1H-MRS), diffusion tensor imaging and high resolution 3D-imaging for morphometric analyses. In particular, 1H-MRS was performed in two regions of interest: the thalami and the anterior cingulate gyrus. Nineteen patients (7M), mean age 34 years (range 19-50) and 14 controls (6 M), mean age 30 years (range 19-40), were included in the final analysis. At the level of the anterior cingulate the ratio of the concentration of N-Acetyl-Aspartate compared to Creatine (NAA/Cr) was significantly reduced in patients compared with controls (p=0,021). A multiple regression analysis was performed, showing that the NAA/Cr ratio in the anterior cingulate in patients correlated with the seizures frequency (p=0,048), being lower in patients with very frequent seizures. As NAA is a marker of integrity, density and neuronal function, we speculate that metabolic changes in specific structures, such as the anterior cingulate, may underlie the pathogenesis of NFLE. Our results open up new possibilities for the use of methodologies of biomedical signal/image processing to characterize the areas involved in the genesis of NFLE, which are currently largely unknown and to further clarify the etiology of this type of epilepsy.

APA, Harvard, Vancouver, ISO, and other styles

24

Naldi, Ilaria <1977&gt. "Studio neuroradiologico (morfologico e funzionale) nei pazienti con Epilessia Frontale Notturna." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5975/.

Full text

Abstract:

L'epilessia frontale notturna (EFN) è caratterizzata da crisi motorie che insorgono durante il sonno. Scopo del progetto è studiare le cause fisiopatologiche e morfo-funzionali che sottendono ai fenomeni motori nei pazienti con EFN e identificare alterazioni strutturali e/o metaboliche mediante tecniche avanzate di Risonanza Magnetica (RM). Abbiamo raccolto una casistica di pazienti con EFN afferenti al Centro Epilessia e dei Disturbi del Sonno del Dipartimento di Scienze Neurologiche, Università di Bologna. Ad ogni paziente è stato associato un controllo sano di età (± 5 anni) e sesso corrispondente. Tutti sono stati studiati mediante tecniche avanzate di RM comprendenti Spettroscopia del protone (1H-MRS), Tensore di diffusione ed imaging 3D ad alta risoluzione per analisi morfometriche. In particolare, la 1H-MRS è stata effettuata su due volumi di interesse localizzati nei talami e nel giro del cingolo anteriore. Sono stati inclusi nell’analisi finale 19 pazienti (7 M), età media 34 anni (range 19-50) e 14 controlli (6 M) età media 30 anni (range 19-40). A livello del cingolo anteriore il rapporto della concentrazione di N-Acetil-Aspartato rispetto alla Creatina (NAA/Cr) è risultato significativamente ridotto nei pazienti rispetto ai controlli (p=0,021). Relativamente all’analisi di correlazione, l'analisi tramite modelli di regressione multipla ha evidenziato che il rapporto NAA/Cr nel cingolo anteriore nei pazienti correlava con la frequenza delle crisi (p=0,048), essendo minore nei pazienti con crisi plurisettimanali/plurigiornaliere. Per interpretare il dato ottenuto è possibile solo fare delle ipotesi. L’NAA è un marker di integrità, densità e funzionalità neuronale. E’ possibile che alla base della EFN ci siano alterazioni metaboliche tessutali in precise strutture come il giro del cingolo anteriore. Questo apre nuove possibilità sull’utilizzo di strumenti di indagine basati sull’analisi di biosegnali, per caratterizzare aree coinvolte nella genesi della EFN ancora largamente sconosciute e chiarire ulteriormente l’eziologia di questo tipo di epilessia. Nocturnal frontal lobe epilepsy (NFLE) is characterized by motor seizuresoccurring during sleep. Aims of the study were to identify the pathophysiological and anatomo-functional factors implicated in the genesis of the motor episodes and possible structural alterations and/or metabolic disorders ,in NFLE patients using advanced techniques of Magnetic Resonance (MR). We have collected a series of patients with NFLE attending the Epilepsy and Sleep Centres of the Department of Neurological Sciences, Bologna University. For each NFLE patient, one control subject of the same sex and age (±5 years) was recruited. All subjects were studied using proton spectroscopy (1H-MRS), diffusion tensor imaging and high resolution 3D-imaging for morphometric analyses. In particular, 1H-MRS was performed in two regions of interest: the thalami and the anterior cingulate gyrus. Nineteen patients (7M), mean age 34 years (range 19-50) and 14 controls (6 M), mean age 30 years (range 19-40), were included in the final analysis. At the level of the anterior cingulate the ratio of the concentration of N-Acetyl-Aspartate compared to Creatine (NAA/Cr) was significantly reduced in patients compared with controls (p=0,021). A multiple regression analysis was performed, showing that the NAA/Cr ratio in the anterior cingulate in patients correlated with the seizures frequency (p=0,048), being lower in patients with very frequent seizures. As NAA is a marker of integrity, density and neuronal function, we speculate that metabolic changes in specific structures, such as the anterior cingulate, may underlie the pathogenesis of NFLE. Our results open up new possibilities for the use of methodologies of biomedical signal/image processing to characterize the areas involved in the genesis of NFLE, which are currently largely unknown and to further clarify the etiology of this type of epilepsy.

APA, Harvard, Vancouver, ISO, and other styles

25

PERRI, KATIA. "OUTCOME NEUROCOGNITIVO E NEURORADIOLOGICO IN BAMBINI AFFETTI DA IPOTIROIDISMO CONGENITO (IC)." Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1008928.

Full text

Abstract:

.OUTCOME NEUROCOGNITIVO E NEURORADIOLOGICO IN BAMBINI AFFETTI DA IPOTIROIDISMO CONGENITO (IC) OBIETTIVI Valutazione neurocognitiva e neuroradiologica in pazienti affetti da ipotiroidismo congenito (IC) permanente e transitorio e controlli. METODI Abbiamo arruolato 41 soggetti (20 F e 21M, età media 9.26 anni ±1.38 sds) con diagnosi di IC (30 permanente e 11 transitorio) effettuata presso il Centro di Screening della Regione Liguria nel periodo tra il 2007 e i maggio 2012. A tutti i soggetti è stata somministrata batteria WISC – IV e altri test per valutare le funzioni cognitive superiori. Dei 41 soggetti solo 35 sono stati sottoposti a RM in quanto i restanti non hanno collaborato sufficientemente per ottenere immagini di buona qualità. RISULTATI Dai risultati emerge un valore medio di QI più elevato nel gruppo di soggetti con IC transitorio (97,09±12,09) rispetto al gruppo con IC permanente che presenta un valore medio nei limiti bassi della norma (88,47±16,59). Anche per le diverse componenti del QI osserviamo punteggi mediamente più elevati nel gruppo IC transitorio con una differenzastatisticamente significativa (p=0.02) per quanto riguarda il ragionamento visuo-percettivo (IRP) . Osservando i punteggi di tutti gli altri test emerge che i soggetti con IC transitorio presentano valori mediamente più elevati rispetto ai soggetti con IC permanente. All’interno dei test per le abilità matematiche vi è una differenza statisticamentesignificativa per la conoscenza numerica (p=0.02).Suddividendo poi i punteggi di tutti i test in grado di disabilità ovvero Normale, Funzionamento Intellettivo limite (FIL) e Disabilità Intellettiva (DI) osserviamo che per quanto riguarda il QI nel gruppo IC transitorio 10 soggetti (90,9%) presentano QI nella norma, solo un soggetto (9,1%) presenta un FIL (QI 70-85) e nessuno DI< (QI < 70). Nel gruppo IC permanente invece 17 soggetti (56,6%) presentano QI nella norma, 8 (26.7%) presentano FIL e 5 (16.7%) invece DI. In tal modo la differenza tra i due gruppi risulta statisticamente significativa (p=0.05). Considerando il solo gruppo IC permanente abbiamo riscontrato correlazioni statisticamente significative (p< 0,005) tra l’età alla diagnosi e quindi l’età di inizio terapia e l’attenzione visiva, la terapia alla diagnosi (mcg/kg/die) e l’attenzione visiva, il TSH alla diagnosi ed il tempo totale di risoluzione di problemi aritmetici. Eseguendo i test psicodiagnostici è stata posta una diagnosi di disturbo dello spettro autistico in un soggetto con IC permanente. Tale diagnosi ha dunque permesso un avvio di percorsi diagnostici terapeutici specifici. Tra tutti i soggetti è stata posta diagnosi di disturbo dello spettro autistico ad un bambino affetto da IC permanente. Questo bambino presenta un QI di 78 compatibile dunque con FIL. Risultano ancora in corso le analisi relative al confronto tra i soggetti con IC e i controlli. È stato ottenuto il consenso per la RM di 35 pazienti su 41. Dei 35 casi sottoposti a RM in 19 casi si sono evidenziate delle alterazioni (11 con IC permanente e 8 con IC transitorio), in particolare a livello della sostanza bianca, regione frontale sottocorticale (rilevate focali iperintensità T2 e FLAIR), e a carico della ghiandola pineale, con presenza talvolta, di cisti a livello di quest’ultima. Tra gli altri reperti incidentali si documentano: sella vuota, dismorfismo della linea mediana, spina sellare, cisti ipofisarie, nodulo eterotopico, gliosi, aracnoidocele, alterazioni dell’ippocampo e del sistema venoso. Risultano ancora in corso le analisi relative allo studio microstrutturale della sostanza bianca ed al confronto tra soggetti con IC e controlli. CONCLUSIONI Dai nostri dati emerge che nei soggetti con IC transitorio vi è una maggiore percentuale di soggetti con QI nella norma rispetto ai soggetti con IC permanente (90.9% vs 56.7%). Globalmente i punteggi ottenuti nei vari test sono mediamente maggiori nei soggetti con IC transitorio rispetto ai soggetti con IC permanente con una differenza statisticamente significativa per il ragionamento visuo percettivo e la conoscenza numerica. L’età di diagnosi e quindi di inizio terapia, il dosaggio di terapia alla diagnosi e il TSH alla diagnosi sono correlati con l’outcome neurocognitivo nei soggetti con IC permanente. Non sono state evidenziate differenze circa alterazioni morfostrutturali alla RM encefalo nei due gruppi.

APA, Harvard, Vancouver, ISO, and other styles

26

Marchitelli, Rocco. "Test-retest Reliability of Intrinsic Human Brain Default-Mode fMRI Connectivity: Slice Acquisition and Physiological Noise Correction Effects." Doctoral thesis, Università degli studi di Trento, 2016. https://hdl.handle.net/11572/368931.

Full text

Abstract:

This thesis aims at evaluating, in two separate studies, strategies for physiological noise and head motion correction in resting state brain FC-fMRI. In particular, as a general marker of noise correction performance we use the test-retest reproducibility of the DMN. The guiding hypothesis is that methods that improve reproducibility should reflect more efficient corrections and thus be preferable in longitudinal studies. The physiological denoising study evaluated longitudinal changes in a 3T harmonized multisite fMRI study of healthy elderly participants from the PharmaCog Consortium (Jovicich et al., 2016). Retrospective physiological noise correction (rPNC) methods were here implemented to investigate their influence on several DMN reliability measures within and between 13 MRI sites. Each site involved five different healthy elderly participants who were scanned twice at least a week apart (5 participants per site). fMRI data analysis was performed once without rPNC and then with WM/CSF regression, with physiological estimation by temporal ICA (PESTICA) (Beall & Lowe, 2007) and FMRIB's ICA-based Xnoiseifier (FSL-FIX) (Griffanti et al., 2014; Salimi-Khorshidi et al., 2014). These methods differ for their data-based computational approach to identify physiological noise fluctuations and need to be applied at different stages of data preprocessing. As a working hypothesis, physiological denoising was in general expected to improve DMN reliability. The head motion study evaluated longitudinal changes in the DMN connectivity from a 4T single-site study of 24 healthy young volunteers who were scanned twice within a week. Within each scanning session, RS-fMRI scans were acquired once using interleaved and then sequential slice-order acquisition methods. Furthermore, brain volumes were corrected for motion using once rigid-body volumetric and then slice-wise methods. The effects of these choices were then evaluated computing multiple DMN reliability measures and investigating single regions within the DMN to assess the existence of inter-regional effects associated with head-motion. In this case, we expected to find slice-order acquisition effects in reliability estimates under standard volumetric motion correction and no slice-order acquisition effect under 2D slice-based motion correction. Both studies used ICA to characterize the DMN using group-ICA and dual regression procedures (Beckmann et al., 2009). This methodology proved successful at defining consistent DMN connectivity metrics in longitudinal and clinical RS-fMRI studies (Zuo & Xing, 2014). Automatic DMN selection procedures and other quality assurance analyses were made to supervise ICA performance. Both studies considered several test-retest (TRT) reliability estimates (Vilagut, 2014) for some DMN connectivity measurements: absolute percent error between the sessions, intraclass correlation coefficients (ICC) between sessions and multiple sites, the Jaccard index to evaluate the degree of voxel-wise spatial pattern actiavtion overlap between sessions.

APA, Harvard, Vancouver, ISO, and other styles

27

Padovan, Giordano B. "Psychoses, language and brain asymmetry: fMRI connectivity alterations in bipolar disorders." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3423164.

Full text

Abstract:

INTRODUCTION A mood characterised by alternating mania and depression have been matter of curiosity and attention since ancient times. According to T.J. Crow’s theory on psychosis, Schizophrenia is strictly linked to the development of the faculty of language (begun in hominids from 6 to 4.2 million years ago) which depends by (anatomical and functional) asymmetry observable between the two cerebral hemispheres (Crow 2004). Several data in the recent (and older) (Griesinger 1845) scientific literature support the hypothesis that schizophrenia and bipolar disorder are similar due to a large number of partially common features: symptomatology, genetics, cognitive features, neurobiology, connectivity alteration, etc.. A brief historical account about how often the classification of this disease changed across the last two centuries may suggest how the knowledge underling this diagnostic category is still fragile. AIM OF THE RESEARCH The goal of this paper is to study Functional Connectivity (FC) among bipolar patients and to test the compatibility of Crow’s paradigm with Bipolar Disorder, verifying the potential presence of hemispheric asymmetry alteration (left dominance deficit) through fMRI analysis. MATERIALS AND METHODS 18 outpatients of the Mood Disorders Unit at the Psychiatric Clinic of the University of Padua have been recruited. All subjects had a diagnosis of Bipolar Disorder type I or type II, according to the criteria of the DSM-IV-TR). 16 healthy individuals were chosen matched for age, sex and education. Clinical and psychological conditions at the time of the experiment were investigated through some psychometric scales widely used for the evaluation of mood, anxiety and other psychopathologic aspects. All subjects underwent a MRI scan both in resting state and while they were attending two tasks: a phonemic (verbal fluency) exercise and a visuo-spatial test (mental rotations). RESULTS From the neuropsychological point of view the phonemic task revealed no significant (p<0.05) differences between groups; on the contrary patients group showed decreased performance at the visuo-spatial task. MRI FC was analysed using two different techniques. Independent Component Analysis (ICA) showed mainly a volume within the Dorsal Attention Network located in left Precuneus (Brodmann Area 7) where patient group presented a reduction of FC compared to controls. Graph analysis brought to light a number of inter-hemispheric and left intra-hemispheric connections revealed to be significantly less active in patients compared to controls, on the contrary substantial conservation of indices at the Network Level was observed. INTRODUZIONE Un tono timico caratterizzato da un’alternanza di mania e depressione è stato oggetto di interesse e attenzione fin dai tempi antichi. Secondo La teoria di T.J. Crow sulla psicosi, la schizofrenia è strettamente legata allo sviluppo della facoltà del linguaggio (che ha avuto origine negli ominidi da 6 a 4,2 milioni di anni fa) che dipende dall'asimmetria (anatomica e funzionale) osservabile tra i due emisferi cerebrali (Crow 2004). Diversi dati nella letteratura scientifica recente (e più antica – Griesinger 1845) supportano l'ipotesi che la schizofrenia e il disturbo bipolare siano simili per un gran numero di caratteristiche parzialmente comuni: sintomatologia, genetica, cognitività, neurobiologia, alterazione della connettività, ecc. Un breve resoconto storico di quanto spesso la classificazione di questa malattia sia cambiata negli ultimi due secoli può suggerire come la conoscenza sottesa a questa categoria diagnostica sia ancora fragile. SCOPO DELLA RICERCA L'obiettivo di questo studio è quello di studiare la connettività funzionale (FC) tra i pazienti bipolari e testare la compatibilità del paradigma di Crow con il disturbo bipolare, verificando la potenziale presenza di alterazioni dell'asimmetria emisferica (deficit di dominanza sinistra) attraverso l'analisi fMRI (risonanza magnetica funzionale). MATERIALI E METODI Sono stati reclutati 18 pazienti ambulatoriali dell'Unità di Disturbi dell'Umore presso la Clinica Psichiatrica dell'Università di Padova. Tutti i soggetti avevano una diagnosi di disturbo bipolare di tipo I o di tipo II, secondo i criteri del DSM-IV-TR). Sono stati scelti 16 individui sani abbinati per età, sesso e istruzione. Le condizioni cliniche e psicologiche al momento dell'esperimento sono state studiate attraverso alcune scale psicometriche ampiamente utilizzate per la valutazione dell'umore, dell'ansia e di altri aspetti psicopatologici. Tutti i soggetti sono stati sottoposti a una risonanza magnetica sia in stato di riposo che durante l’esecuzione di due compiti: un esercizio fonemico (fluenza verbale) e un test visuo-spaziale (rotazioni mentali). RISULTATI Dal punto di vista neuropsicologico, il compito fonemico non ha rivelato differenze significative (p<0.05) tra i gruppi; al contrario, il gruppo di pazienti ha mostrato una riduzione delle prestazioni nel compito visuo-spaziale. I dati fMRI sono stati analizzati utilizzando due tecniche diverse. L'Independent Component Analysis (ICA) ha mostrato principalmente un volume all'interno della Dorsal Attention Network situato nel precuneo sinistro (area 7 di Brodmann) dove il gruppo di pazienti presentava una riduzione significativa della FC rispetto ai controlli. L'analisi dei grafi ha portato alla luce un numero di connessioni intra-emisferiche e intra-emisferiche di sinistra rivelate significativamente meno attive nei pazienti rispetto ai controlli, al contrario è stata osservata una sostanziale conservazione degli indici a livello di rete.

APA, Harvard, Vancouver, ISO, and other styles

28

Marchitelli, Rocco. "Test-retest Reliability of Intrinsic Human Brain Default-Mode fMRI Connectivity: Slice Acquisition and Physiological Noise Correction Effects." Doctoral thesis, University of Trento, 2016. http://eprints-phd.biblio.unitn.it/1709/1/ROCCO_MARCHITELLI_CIMEC_PHD_THESIS_30032016.pdf.

Full text

Abstract:

This thesis aims at evaluating, in two separate studies, strategies for physiological noise and head motion correction in resting state brain FC-fMRI. In particular, as a general marker of noise correction performance we use the test-retest reproducibility of the DMN. The guiding hypothesis is that methods that improve reproducibility should reflect more efficient corrections and thus be preferable in longitudinal studies. The physiological denoising study evaluated longitudinal changes in a 3T harmonized multisite fMRI study of healthy elderly participants from the PharmaCog Consortium (Jovicich et al., 2016). Retrospective physiological noise correction (rPNC) methods were here implemented to investigate their influence on several DMN reliability measures within and between 13 MRI sites. Each site involved five different healthy elderly participants who were scanned twice at least a week apart (5 participants per site). fMRI data analysis was performed once without rPNC and then with WM/CSF regression, with physiological estimation by temporal ICA (PESTICA) (Beall & Lowe, 2007) and FMRIB's ICA-based Xnoiseifier (FSL-FIX) (Griffanti et al., 2014; Salimi-Khorshidi et al., 2014). These methods differ for their data-based computational approach to identify physiological noise fluctuations and need to be applied at different stages of data preprocessing. As a working hypothesis, physiological denoising was in general expected to improve DMN reliability. The head motion study evaluated longitudinal changes in the DMN connectivity from a 4T single-site study of 24 healthy young volunteers who were scanned twice within a week. Within each scanning session, RS-fMRI scans were acquired once using interleaved and then sequential slice-order acquisition methods. Furthermore, brain volumes were corrected for motion using once rigid-body volumetric and then slice-wise methods. The effects of these choices were then evaluated computing multiple DMN reliability measures and investigating single regions within the DMN to assess the existence of inter-regional effects associated with head-motion. In this case, we expected to find slice-order acquisition effects in reliability estimates under standard volumetric motion correction and no slice-order acquisition effect under 2D slice-based motion correction. Both studies used ICA to characterize the DMN using group-ICA and dual regression procedures (Beckmann et al., 2009). This methodology proved successful at defining consistent DMN connectivity metrics in longitudinal and clinical RS-fMRI studies (Zuo & Xing, 2014). Automatic DMN selection procedures and other quality assurance analyses were made to supervise ICA performance. Both studies considered several test-retest (TRT) reliability estimates (Vilagut, 2014) for some DMN connectivity measurements: absolute percent error between the sessions, intraclass correlation coefficients (ICC) between sessions and multiple sites, the Jaccard index to evaluate the degree of voxel-wise spatial pattern actiavtion overlap between sessions.

APA, Harvard, Vancouver, ISO, and other styles

29

COLELLI, GIULIA. "Artificial Intelligence, Mathematical Modeling and Magnetic Resonance Imaging for Precision Medicine in Neurology and Neuroradiology." Doctoral thesis, Università degli studi di Pavia, 2022. https://hdl.handle.net/11571/1468414.

Full text

Abstract:

La tesi affronta la possibilità di utilizzare metodi matematici, tecniche di simulazione, teorie fisiche riadattate e algoritmi di intelligenza artificiale per soddisfare le esigenze cliniche in neuroradiologia e neurologia al fine di descrivere e prevedere i patterns e l’evoluzione temporale di una malattia, nonché di supportare il processo decisionale clinico. La tesi è suddivisa in tre parti. La prima parte riguarda lo sviluppo di un workflow radiomico combinato con algoritmi di Machine Learning al fine di prevedere parametri che favoriscono la descrizione quantitativa dei cambiamenti anatomici e del coinvolgimento muscolare nei disordini neuromuscolari, con particolare attenzione alla distrofia facioscapolo-omerale. Il workflow proposto si basa su sequenze di risonanza magnetica convenzionali disponibili nella maggior parte dei centri neuromuscolari e, dunque, può essere utilizzato come strumento non invasivo per monitorare anche i più piccoli cambiamenti nei disturbi neuromuscolari oltre che per la valutazione della progressione della malattia nel tempo. La seconda parte riguarda l’utilizzo di un modello cinetico per descrivere la crescita tumorale basato sugli strumenti della meccanica statistica per sistemi multi-agente e che tiene in considerazione gli effetti delle incertezze cliniche legate alla variabilità della progressione tumorale nei diversi pazienti. L'azione dei protocolli terapeutici è modellata come controllo che agisce a livello microscopico modificando la natura della distribuzione risultante. Viene mostrato come lo scenario controllato permetta di smorzare le incertezze associate alla variabilità della dinamica tumorale. Inoltre, sono stati introdotti metodi di simulazione numerica basati sulla formulazione stochastic Galerkin del modello cinetico sviluppato. La terza parte si riferisce ad un progetto ancora in corso che tenta di descrivere una porzione di cervello attraverso la teoria quantistica dei campi e di simularne il comportamento attraverso l'implementazione di una rete neurale con una funzione di attivazione costruita ad hoc e che simula la funzione di risposta del modello biologico neuronale. E’ stato ottenuto che, nelle condizioni studiate, l'attività della porzione di cervello può essere descritta fino a O(6), i.e, considerando l’interazione fino a sei campi, come un processo gaussiano. Il framework quantistico definito può essere esteso anche al caso di un processo non gaussiano, ovvero al caso di una teoria di campo quantistico interagente utilizzando l’approccio della teoria wilsoniana di campo efficace. The thesis addresses the possibility of using mathematical methods, simulation techniques, repurposed physical theories and artificial intelligence algorithms to fulfill clinical needs in neuroradiology and neurology. The aim is to describe and to predict disease patterns and its evolution over time as well as to support clinical decision-making processes. The thesis is divided into three parts. Part 1 is related to the development of a Radiomic workflow combined with Machine Learning algorithms in order to predict parameters that quantify muscular anatomical involvement in neuromuscular diseases, with special focus on Facioscapulohumeral dystrophy. The proposed workflow relies on conventional Magnetic Resonance Imaging sequences available in most neuromuscular centers and it can be used as a non-invasive tool to monitor even fine change in neuromuscular disorders and to evaluate longitudinal diseases’ progression over time. Part 2 is about the description of a kinetic model for tumor growth by means of classical tools of statistical mechanics for many-agent systems also taking into account the effects of clinical uncertainties related to patients’ variability in tumor progression. The action of therapeutic protocols is modeled as feedback control at the microscopic level. The controlled scenario allows the dumping of uncertainties associated with the variability in tumors’ dynamics. Suitable numerical methods, based on Stochastic Galerkin formulation of the derived kinetic model, are introduced. Part 3 refers to a still-on going project that attempts to describe a brain portion through a quantum field theory and to simulate its behavior through the implementation of a neural network with an ad-hoc activation function mimicking the biological neuron model response function. Under considered conditions, the brain portion activity can be expressed up to O(6), i.e., up to six fields interaction, as a Gaussian Process. The defined quantum field framework may also be extended to the case of a Non-Gaussian Process behavior, or rather to an interacting quantum field theory in a Wilsonian Effective Field theory approach.

APA, Harvard, Vancouver, ISO, and other styles

30

WAKABAYASHI, TOSHIHIKO, MASAZUMI FUJII, YASUKAZU KAJITA, ATSUSHI NATSUME, SATOSHI MAEZAWA, and JUN YOSHIDA. "ADVANCED NEW NEUROSURGICAL PROCEDURE USING INTEGRATED SYSTEM OF INTRAOPERATIVE MRI AND NEURONAVIGATION WITH MULTIMODAL NEURORADIOLOGICAL IMAGES." Nagoya University School of Medicine, 2009. http://hdl.handle.net/2237/12346.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Freytag, Sascha [Verfasser], and Florian [Akademischer Betreuer] Beißner. "Darstellung einer evidenzbasierten Karte der Headschen Zonen / Sascha Freytag ; Akademischer Betreuer: Florian Beißner ; Institut für Diagnostische und Interventionelle Neuroradiologie." Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2019. http://d-nb.info/1201833760/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Santos, Vives Alicia. "Estudio neuropsicológico, neurorradiológico y clínico en el hipercortisolismo endógeno = Neuropsychological, neuroradiological and clinical study in endogenous hypercortisolism." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/384710.

Full text

Abstract:

Endogenous Cushing’s syndrome is a rare disease due to an excess of circulating cortisol. Chronic cortisol excess can lead to different comorbidities which may persist after biochemical cure, including brain volume decrease, neuropsychological impairment, mood disorders and high cardiovascular risk. This PhD thesis aims to study some of the effects of Cushing’s syndrome on the brain, and its relationship to other clinical parameters. More specifically, the aims of this thesis include analyzing cerebellar volume in patients with Cushing’s syndrome and establishing associations with neuropsychological performance, cortisol levels and other clinical parameters. On the other hand, it pretends to analyse brain white matter lesions in patients with Cushing’s syndrome and the relationship between cardiovascular risk, white matter lesions, neuropsychological performance and brain volume. Our results showed smaller cerebellar cortex volumes in active patients, but not in patients in remission, in comparison to controls. Cerebellar cortex positively correlated with visual memory performance and quality of life, and negatively correlated with age at diagnosis and triglyceride levels. Active patients had worse memory performance than controls. Both patient groups had higher anxiety and depression levels than controls. Patients in remission (but not active patients) had a higher degree of white matter lesions than controls. White matter lesions where correlated to diastolic blood pressure and duration of hypertension. Patients in remission on hydrocortisone replacement had higher level of white matter lesions than patients in remission not taking hydrocortisone. Finally, both patient groups (active and in remission) had higher cardiovascular risk than controls. Cardiovascular risk negatively correlated with cognitive function and cerebellar volume in patients in remission. In conclusion, Cushing’s syndrome leads to different comorbidities in the two phases of the disease (active and in remission). Some of the alterations found in active patients may be, at least, partially reversible, although the cardiovascular risk associated with Cushing’s syndrome may lead to further comorbidities in the future if it is not controlled. These data highlight the importance of providing psychological support to the patients if necessary and controlling cardiovascular risk in order to prevent brain damage and to reduce the risk of stroke or heart attack. El síndrome de Cushing endógeno es una enfermedad rara debida a un exceso de cortisol circulante. El exceso crónico de cortisol puede provocar una serie de alteraciones que no en todos los casos revierten tras la curación hormonal, y que incluyen disminución del volumen cerebral, alteraciones neuropsicológicas y del estado de ánimo y riesgo cardiovascular elevado. Esta tesis pretende estudiar algunos de los efectos que provoca el síndrome de Cushing a nivel cerebral, analizando su relación con otros parámetros clínicos. Concretamente, los objetivos de la tesis incluyen por un lado analizar el volumen cerebelar en los pacientes con síndrome de Cushing, así como establecer su relación con el rendimiento neuropsicológico, los niveles de cortisol y otros parámetros clínicos. Por otro lado, se pretende analizar la presencia de lesiones de sustancia blanca cerebral en los pacientes con síndrome de Cushing y la relación entre riesgo cardiovascular, lesiones de sustancia blanca, rendimiento neuropsicológico y volumen cerebral. Se encontraron menores volúmenes del córtex cerebelar bilateral en los pacientes activos, pero no en los pacientes curados, en comparación con los controles. El córtex cerebelar correlacionó positivamente con el rendimiento en memoria visual y la calidad de vida y negativamente con la edad en el momento del diagnóstico y el nivel de triglicéridos circulantes. Los pacientes activos presentaban peor rendimiento a nivel de memoria, y ambos grupos de pacientes presentaban mayores niveles de ansiedad y depresión que los controles sanos. Por otro lado, los pacientes en remisión, pero no los pacientes activos presentaron mayor nivel de lesiones de sustancia blanca cerebral que los controles sanos. Estas lesiones estaban relacionadas con los niveles de tensión diastólica y la duración de la hipertensión. Los pacientes en remisión que tomaban hidrocortisona presentaban mayor nivel de lesiones que los pacientes en remisión que no tomaban el fármaco. Finalmente ambos grupos de pacientes (activos y en remisión) presentaban mayor riesgo cardiovascular que los controles sanos. El riesgo cardiovascular correlacionó negativamente con la función cognitiva y el volumen cerebral en los pacientes en remisión. En conclusión, el síndrome de Cushing determina diferentes comorbilidades en las distintas fases de la enfermedad. Algunas de las alteraciones halladas en los pacientes activos podrían ser al menos parcialmente reversibles, aunque el riesgo cardiovascular asociado a la enfermedad puede llevar a otras comorbilidades en el futuro si no se controla. Estos datos remarcan la importancia de proporcionar un soporte psicológico a los pacientes en caso necesario y de controlar el riesgo vascular para prevenir la posible afectación cerebral futura y reducir el riesgo de complicaciones cardiovasculares.

APA, Harvard, Vancouver, ISO, and other styles

33

Li, Na [Verfasser]. "Neuroradiological findings and molecular markers as predictors for secondary brain injury and outcome after intracerebral hemorrhage / Na Li." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2012. http://d-nb.info/1030331650/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Gottstein, Stefanie [Verfasser]. "Charité - Umstrukturierung an einem großen deutschen Universitätsklinikum : Allgemeine und spezielle Aspekte eines Reformprozesses aus Sicht des Querschnittsfaches Radiologie/Neuroradiologie / Stefanie Gottstein." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2009. http://d-nb.info/1023373610/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Souza, João Augusto Leonel de [UNESP]. "Pressão subaracnóide, índice pressão volume e parâmetros cardiorrespiratórios em ovinos submetidos a mielografia lombar." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/143861.

Full text

Abstract:

Submitted by JOÃO AUGUSTO LEONEL DE SOUZA null (desouza.ja@gmail.com) on 2016-09-09T16:38:02Z No. of bitstreams: 1 Dissertação final.pdf: 1556586 bytes, checksum: e53dadd03ff83fdae3ae4b4e49d912ac (MD5) Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-13T13:15:00Z (GMT) No. of bitstreams: 1 souza_jal_me_jabo.pdf: 1556586 bytes, checksum: e53dadd03ff83fdae3ae4b4e49d912ac (MD5) Made available in DSpace on 2016-09-13T13:15:00Z (GMT). No. of bitstreams: 1 souza_jal_me_jabo.pdf: 1556586 bytes, checksum: e53dadd03ff83fdae3ae4b4e49d912ac (MD5) Previous issue date: 2016-05-30 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) A mielografia é muito realizada na prática veterinária, entretanto, existem importantes efeitos adversos associados a ela. O objetivo da presente pesquisa foi avaliar os possíveis efeitos sobre a pressão subaracnoide, parâmetros cardiorrespiratórios (TC, FR, FC, PAS, PAD, PAM, EtCO2, SpO2, InspISO e FeISO) e do índice de pressão-volume (PVI) em ovelhas hígidas submetidas à mielografia lombar. Foram utilizados 8 ovinos fêmeas sadios, os quais foram pré-medicados com Midazolan (0,5 mg/Kg), indução anestésica com Propofol (3-6 mg/Kg) e manutenção anestésica com Isoflurano. Primeiramente, os animais foram submetidos à punção da cisterna magna para monitoramento da pressão subaracnoide (Sap). Ato contínuo, foi realizado a mielografia lombar por meio da aplicação de Iohexol (300 mg/mL, taxa de 4,1 mL/min e dose de 0,4 mL/Kg). Os momentos estudados foram: imediatamente após a estabilização anestésica (M0), durante a punção lombar (M1), dois, quatro e seis minutos após a aplicação do contraste (M2, M3 e M4, respectivamente). A Sap foi colhida imediatamente após à punção atlanto-occipital (Sap0), o maior valor durante a aplicação do meio de contraste (Sapmax), dois, quatro e seis minutos após a aplicação do meio de contraste (Sap2, Sap3 e Sap4, respectivamente). Constataram-se diferenças significativas a 5% de confiança entre os momentos as variáveis: TC, PAS, PAD, PAM, InspISO, FeISO Sap e PPC pelo teste de Tukey. Com a correlação de Pearson TC/FR, FC/SpO2, FC/FR, FR/PAS, FR/PAD, FR/PAM, FR/PPC, Sap/PAS, PAD/Sap, PAM/Sap, EtCO2/SPO2, EtCO2/InsplSO, PAD/PAS, PAS/PAM, PAM/PAD, FelSO/InsplSO e Sap/PPC. Com base nos resultados concluímos que os valores de PVI, para a espécie ovina, com a metodologia empregada foi de 17,91 mL. Durante a realização da mielografia lombar ocorre aumento significativo da Sap (média de 101,87 mmHg), provocando grave redução da PPC. The myelography is very accomplished in veterinary practice, however there are significant adverse effects associated with it. The aim of this research was to evaluate the possible effects of subarachnoid pressure, cardiorespiratory parameters (TC, FR, FC, PAS, PAD, PAM, EtCO2, SpO2, InspISO and FeISO) and pressure-volume index (PVI) in sheep otherwise healthy undergoing lumbar myelography. 8 healthy female sheep were used, which were pre-medicated with midazolam (0.5 mg / kg) anesthetic induction with propofol (3-6 mg / kg) and anesthesia maintained with isoflurane. First, the animals were submitted to the puncture of the cisterna magna and pressure monitoring. Subsequently, the lumbar myelography was performed by application of iohexol (300 mg / ml at rate 4.1 ml / min and a dose of 0.4 ml / kg). The time points studied were: immediately after anesthetic stabilization (M0) during a lumbar puncture (M1), two, four and six minutes after application of contrast (M2, M3 and M4, respectively). Subarachnoid pressure (Sap) was taken immediately after the atlanto-occipital punch (Sap0), the largest value during application of the contrast medium (Sapmax), two, four and six minutes after application of the contrast medium (SAP2, Sap3 and Sap4, respectively). They found significant differences at 5% confidence between times the variables TC, PAS, PAD, PAM, InspISO, FeISO Sap and PPC by Tukey test. With the Pearson correlation TC/FR, FC/SpO2, FC/FR, FR/PAS, FR/PAD, FR/PAM, FR/PPC, Sap/PAS, PAD/Sap, PAM/Sap, EtCO2/SPO2, EtCO2/InsplSO, PAD/PAS, PAS/PAM, PAM/PAD, FelSO/InsplSO and Sap/PPC Based on the results we conclude that the PVI values for the sheep, the methodology employed was 17.91 mL, close to normal values for adults of the human species. While performing the lumbar myelography is significant increase in Sap (average of 101.87 mmHg), causing severe reduction in PPC.

APA, Harvard, Vancouver, ISO, and other styles

36

Gehling, Kim Gina [Verfasser], Jan S. [Akademischer Betreuer] Kirschke, Jan S. [Gutachter] Kirschke, and Christian [Gutachter] Schulz. "Simulation diagnostischer Angiographien zur Ausbildung in der interventionellen Neuroradiologie / Kim Gina Gehling ; Gutachter: Jan S. Kirschke, Christian Schulz ; Betreuer: Jan S. Kirschke." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1220321060/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Taleb-Ahmed, Abdelmalik. "Étude de techniques de représentation 3D d'objets biologiques à partir d'acquisitions radiologiques X et IRM, applications en neuroradiologie et en morphogenèse céphalique." Lille 1, 1992. http://www.theses.fr/1992LIL10026.

Full text

Abstract:

Les systèmes de radiologie tels que les scanners X, IRM, nucléaires, acoustiques possèdent aujourd'hui des logiciels de reconstruction et de représentation 3D très performants. Seulement, ces systèmes ont leurs fonctions figées conformes à des protocoles cliniques et les résultats des traitements ne permettent pas aux médecins d'obtenir des informations utiles à leurs besoins de recherche. Le travail présenté est relatif à l'étude d'une classe de systèmes complémentaires capables à partir de données d'acquisitions radiologiques de reconstruire, représenter et manipuler en 3D des objets biologiques pour effectuer des mesures diverses (investigations profondes, gestes assistés par ordinateur, conception de prothèses. . . ). La première partie consiste en une étude bibliographique des différentes méthodes de modélisation et de visualisation 3D. La deuxième partie est relative à l'étude d'une chaîne fonctionnelle de représentation 3D d'objets biologiques à partir de coupes parallèles issues d'une reconstruction 2D. Dans le cas de l'application en neuroradiologie de la représentation 3D du réseau vasculaire du cou, nous présentons des solutions originales que nous avons développées sur une méthode d'échantillonnage de contours de formes 2D quelconques, sur une base de données 3D structurée et sur des algorithmes de triangulation de formes 3D bifurquées. La troisième partie est relative de la représentation 3D d'objets de la machine à partir de 3 clichés orthographiques. Après l'exposé d'une émthode d'orthogonalisation des clichés que nous avons mise au point, nous présentons l'étude de la représentation 3D en ramenant le problème à celui de la reconstruction 2D suivi de la méthode de représentation 3D décrite dans la 2ème partie. La reconstruction 2D est rendue pratiquement impossible quand on ne dispose que les contours des objets sur les clichés orthographiques sans connaître les profils de densité. C'est par exemple le cas de la reconstruction des dents à partir de radiographies X. Dans ce cas, nous proposons une solution qui consiste à se servir des profils de densité de modèles associés aux contours relevés sur les clichés radiographiques. Nous développons cette méthode à l'aide d'un algorithme de flot à coût minimal dont nous discutons les résultats et nous donnons des exemples de reconstruction en morphogenèse céphalique

APA, Harvard, Vancouver, ISO, and other styles

38

WAKABAYASHI, T., T. NAITO, T. KINKORI, et al. "Can Periprocedural Hypotension in Carotid Artery Stenting Be Predicted ? : A Carotid Morphologic Autonomic Pathologic Scoring Model Using Virtual Histology to Anticipate Hypotension." Thesis, Centauro Srl, 2009. http://hdl.handle.net/2237/16865.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Aberdour, Mark J. "Changes in Platelet Aggregation and Activation in Patients Undergoing Interventional Neuroradiology Procedures: Can Point-Of-Care Devices Assist in Predicting Complications?" Thesis, Griffith University, 2019. http://hdl.handle.net/10072/389745.

Full text

Abstract:

Introduction/Aims: Patients undergoing interventional neuroradiology (IVN) procedures to treat intracranial aneurysms experience a minor, but potentially life threatening risk of thromboembolic or haemorrhagic complications. Antiplatelet medications, such as clopidogrel and aspirin, are routinely administered pre-operatively for elective IVN procedures to reduce the risk of thromboembolic events. There are known hyper- or hypo-effective responses to these pre-operative antiplatelet medications, notably clopidogrel, which may insufficiently inhibit platelet function in some patients and increase the risk of complication. The point-of-care (POC) Multiplate® analyser was used to assess platelet function (aggregation) at numerous time points. Patient outcome (ie. those who suffered surgical complications, and those who did not) was assessed to establish whether platelet functionality was related to IVN complication. Additionally, analysing platelet response data in patients with and without complications aimed to establish the potential diagnostic value of Multiplate® response for negative clinical outcomes. In addition, platelet aggregation as recorded by Multiplate® analysis was with platelet activation as assessed using flow cytometry in an attempt to compare functional Multiplate® data to sensitive molecular activation markers. Methods: This project received ethical approval from Griffith University and the Gold Coast University Hospital (GCUH), including amendments for the inclusion of flow cytometric analysis. Demographic and surgical data, as well as blood samples were collected from adult patients admitted to the GCUH for elective or emergent treatment of intracranial aneurysms between March 2015 and April 2018. Blood samples were collected at five separate time points: admission (pre-antiplatelet administration), pre-operatively (post-antiplatelet administration), post-surgically, and at days 1 and 4 post-operatively. The samples of 120 patients and 131 procedures were analysed on Multiplate®, while 12 matched patient samples were also analysed using a BD LSRFortessa™ Cell Analyser for flow cytometric analysis. Samples were collected from elective and emergent (ruptured aneurysm) patients. The main variable of interest were the extent of platelet aggregation/activation at each time point, as well as any peri- or post—surgical complications the patient experienced. Results: Analysis of the 120 patients showed that pre-operative aspirin and clopidogrel administration significantly reduced platelet aggregation (Multiplate®) and platelet activation (flow cytometry). A total of 26 complications were recorded including ischaemic, haemorrhagic events, vasospasm and evidence of temporary neurological deficit. Elective patients who suffered complications (composite score of all adverse events) had significantly higher pre-operative, ADP-induced Multiplate® scores compared to their non-complication counterparts (P<0.05). There were no significant differences in Multiplate® scores in the elective cohort when comparing the non-complication group to those who suffered ischaemic or haemorrhagic complications specifically (P>0.05). Furthermore, Multiplate® scores did not differ in patients in non-complication versus complications within the emergent cohort. ROC analysis of pre-operative Multiplate® data demonstrated that a ADP-induced platelet aggregation score of >31.5AUC was a significant predictor of elective complications (i.e. all complications excluding haemorrhagic). This allowed successful identification of 88.89% (i.e. sensitivity) of surgical complications pre-surgically by assessing their platelet aggregation with a 34.62% false positive rate. There were no significant predictors of haemorrhagic complication, or for any type of emergent complication. Platelet activation recorded by flow cytometry followed a similar trend over time to platelet aggregation as recorded by Multiplate® analyser. “A significant but weak correlation between flow cytometric and Multiplate® analysis was established for agonists including ADP (p=>0.01, r2=0.32) and TRAP-6 (p=0.05, r 2= 0.12). Conclusion: Elective patients experience significant inhibition of platelet function following antiplatelet administration for IVN procedures as recorded by Multiplate®. Furthermore, this study demonstrated, for the first time, that pre-operative ADP induced platelet aggregation can sensitively predict patients’ risk of experiencing thromboembolic events and/or vasospasm. However, the predictive values established are only reliable for elective patients and do not predict haemorrhagic complications. This is likely due to the small number of patients suffering complication throughout the study. This thesis also presents the first data to compare and potentially validate Multiplate® recorded platelet aggregation against flow cytometry analysis for platelet activation. Thesis (Masters) Master of Medical Research (MMedRes) School of Medical Science Griffith Health Full Text

APA, Harvard, Vancouver, ISO, and other styles

40

Del, Missier Nathalie. "Matériovigilance et traçabilité des dispositifs médicaux implantables utilisés en neuroradiologie vasculaire dans le traitement des anévrismes intracraniens : exemple des GDC R à l'hôpital Sainte-Anne." Paris 5, 1998. http://www.theses.fr/1998PA05P210.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Barrmeyer, Johanna Amelie [Verfasser], and Katja [Akademischer Betreuer] Derlin. "Multiparametrische funktionelle Magnetresonanztomografie zur nicht-invasiven Beurteilung von pathologischen Veränderungen der Transplantatniere in Mausmodellen / Johanna Amelie Barrmeyer ; Akademischer Betreuer: Katja Derlin ; Institut für Diagnostische und Interventionelle Neuroradiologie." Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2019. http://d-nb.info/1186637994/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Goede, Lukas Laurids [Verfasser], and Karin [Akademischer Betreuer] Weißenborn. "Analyse mikrostruktureller Veränderungen des Gehirns unter langfristiger Therapie mit Calcineurininhibitoren nach Lebertransplantation mittels quantitativer Magnetresonanztomografie / Lukas Laurids Goede ; Akademischer Betreuer: Karin Weißenborn ; Klinik für Neurologie, Institut für Diagnostische und Interventionelle Neuroradiologie." Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2021. http://d-nb.info/1236024265/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

GIOENI, DANIELA. "THE INFLUENCE OF ANESTHESIA IN THE CENTRAL NERVOUS SYSTEM STUDY." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/708703.

Full text

Abstract:

Central nervous system is a complex machine; it is constituted by more or less 172 billions of cells divided between neurons and glia. This incredible number of cells, particularly neurons, are constantly connected, working 24 hours a day, never stopping. Their activity is maintained even during particular conditions such as sleep, pathological unconsciousness (coma) or general anesthesia. For all these peculiarities, since ancient times, man has devoted much effort to the study of the most fascinating organ of living beings (mammals in particular). Nowadays, thanks to the advance in medical technology, many tools are available to “look inside the brain”. Magnetic resonance imaging and, particularly, functional magnetic resonance imaging (fMRI) is a modern biomedical imaging method, which allows a non-invasive assessment of brain function. The detection of brain activity is based on the coupling between neuronal activity, energy consumption, and blood flow. Functional connectivity (FC) of brain regions is modulated in various central nervous system diseases, during sleeping and general anesthesia. Anesthesia during MRI procedures is commonly used in preclinical setting and, sometimes, is required also in clinical setting (uncollaborative patients, children, drugs induced-coma etc). The study of the relationship between anesthetics and FC presents a double value: allows to distinguish the alterations induced by anesthesia on FC, avoiding possible confounding elements, and permits an in depth investigation of drugs behaviour. For all these reasons, the main topic of this PhD dissertation is the relationship between anesthesia and central nervous system. We started from theoretical studies in healthy subjects and we arrived to clinical setting, describing the possible application of anesthetics drugs as a treatment of neurologic diseases. The first study included aims to describe the way in which dexmedetomidine and isoflurane modulate FC in guinea pigs. We analysed the characteristic of cortical, subcortical and cortico- subcortical connectivity under both drugs with resting state fMRI. The second study presented partial results of a more complex work concerning FC in rats under 4 different anesthetics protocols. Because in FC studies blood flow represents a crucial element we dedicated a part of the work to the study of haemodynamic alterations through the administration 3 of contrast medium. Dynamic Suceptibility Contrast MRI analysis allows the study of cerebral blood flow and cerebral blood volume of different brain anatomic regions under dexmedetomidine, isoflurane, midazolam-dexmedetomidine and midazolam-isoflurane. Finally, we moved to clinical setting to describe the successful treatment of 3 dogs suffering from idiopathic epilepsy presented in emergency department in a state of super refractory status epilepticus. They were treated successfully with a continuous infusion of dexmedetomidine and ketamine. In conclusion, taken together this thesis gives a little contribute to better understand anesthetics behavior at brain level. We believe that it is important to make a “rational choice” when we decide the anesthetic protocol for neuroimaging procedures (both in clinical and preclinical setting) and this “rational choice” could be make only if we have a widespread literature that describe the highest number of anesthetic protocol and their interaction on central nervous system. Finally, thanks to the continuous improvement of our understanding of anesthetics mechanism of action, especially from a molecular and functional point of view, is it possible to use different anesthetics as a therapy for different neurologic conditions, particularly the one based on neurotransmitters imbalance.

APA, Harvard, Vancouver, ISO, and other styles

44

Hirt, Lukas Andreas [Verfasser], and Florian [Akademischer Betreuer] Beißner. "Auswirkungen qualitativer Aspekte von Körperbewegung auf die Hauttemperatur : eine randomisierte Studie zur Eurythmie Therapie / Lukas Andreas Hirt ; Akademischer Betreuer: Florian Beißner ; Institut für Diagnostische und Interventionelle Neuroradiologie, ARCIM-Institute der Filderklinik in Filderstadt." Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2020. http://d-nb.info/1214251153/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Schmitz, Birte [Verfasser], Xiaoqi [Akademischer Betreuer] Ding, and Karin [Akademischer Betreuer] Weißenborn. "Investigation of metabolic and microstructural alterations in human brain under physiological and pathological conditions by using magnetic resonance imaging and 1H and 31P magnetic resonance spectroscopy / Birte Schmitz ; Akademische Betreuer: Xiaoqi Ding, Karin Weißenborn ; Institut für Diagnostische und Interventionelle Neuroradiologie." Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2020. http://d-nb.info/1225413656/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Júnior, Antenor Tavares de Sá. "Alterações de difusão e perfusão cerebral por RM em angioplastia carotídea com \"stent\" sob proteção cerebral por filtros." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/5/5151/tde-22022010-171639/.

Full text

Abstract:

INTRODUÇÃO: A angioplastia carotídea com stent (ACS) sob proteção cerebral é opção terapêutica em pacientes com estenose carotídea. Existe o risco de embolia apesar da utilização do filtro e as modificações na perfusão cerebral após tratamento da estenose carotídea não são claras. O propósito deste estudo é avaliar, após ACS sob proteção cerebral por filtros, modificações nas seqüências de RM de difusão (DWI) e perfusão (PWI), correlacionando-as com os aspectos técnicos da ACS, com as características da estenose e com dados demográficos dos pacientes. MÉTODO: Trinta e seis pacientes portadores de estenose carotídea com idade média de 72,08 anos foram submetidos a exame de RM um dia antes e até 72 horas após a ACS com filtro de proteção. Todos os pacientes eram assintomáticos após a ACS. Áreas de restrição na DWI após a ACS foram correlacionadas com aspectos demográficos, com aspectos da técnica de angioplastia e com a presença de infartos prévios por RM. Os parâmetros CBV volume sanguíneo cerebral, MTT tempo de trânsito médio e TTP tempo para o pico são empregados para análise por PWI. RESULTADOS: Na DWI, 18 de 36 (50,00%) pacientes apresentaram novos focos (NF) de restrição na DWI após ACS. Todos os NF foram clinicamente silenciosos (100%). Estes NF eram localizados em território cerebral nutrido pela artéria carótida submetida à ACS em 77,19% e menores que 10 mm em 91,53%. Os NF em território cerebral não irrigado pela artéria carótida submetida à angioplastia correspondiam a 22,81% destes. A presença de infartos cerebrais prévios na RM foi o único fator com influência no aparecimento de NF (p=0,037). Fatores demográficos e aspectos relacionados com a técnica de angioplastia não tiveram importância na gênese dos NF. Na PWI foi observada melhora nos parâmetros temporais TTP (p<0,001) e MTT (p=0,019) quando comparados de forma normalizada em relação ao território contralateral. CONCLUSÃO: Os novos focos de restrição na DWI após ACS (NF) foram mais comuns no território ipsilateral (77,19%), no entanto houve NF no território contralateral à ACS (22,81%), possivelmente, associados ao cateterismo diagnóstico. Os NF, na sua maioria, são de pequeno diâmetro (<10 mm em 91,53%). Melhora precoce na PWI, observada nos dados normalizados, foi demonstrada nos parâmetros temporais (TTP e MTT). INTRODUCTION: Carotid angioplasty with stent (CAS) under cerebral protection is a therapeutic option in patients with carotid stenosis. There is a risk of embolism even with a filter, and changes in cerebral perfusion after treatment are not clearly understood. The purpose of this study was to evaluate changes in diffusion- (DWI) and perfusion- (PWI) weighted magnetic resonance imaging (MRI) sequences correlating them with the technical aspects of CAS, stenosis characteristics and patient demographic data. METHODS: Thirty-six carotid stenosis patients with an mean age of 72.08 years were submitted to MRI exam one day before and up to 72 hours after CAS with filter protection. All patients were asymptomatic after CAS. Areas of restriction on DWI were correlated to demographic aspects, technique of angioplasty as well the presence of previous stroke by MRI. The parameters, CBV - cerebral blood volume; MTT - mean transit time, and TTP- time to peak, are used for PWI analysis. RESULTS: Eighteen of the 36 patients (50.00%) presented new focus (NF) of restriction by DWI after CAS. All new focus were clinically silent. The NF were located in the cerebral area fed by the carotid artery submitted to CAS in 77.19% and smaller than 10mm in 91.53%. NF in cerebral area not irrigated by carotid artery submitted by angioplasty correspond to 22,81 %. The presence of previous ischemic lesion on MRI was the only factor which influenced the appearance of NF (p=0.037). Demographic factors and aspects related to angioplasty technique had no importance on NF genesis. Improvement in PWI timing parameters - TTP (p<0.001) and MTT (p=0.019) were observed in relation to the contralateral territory (normalized data). CONCLUSION: The restriction NF in the DWI after CAS are more common in the ipsilateral territory (77.19%), however there were some NF in the contralateral territory to the CAS (22.81%), possibly associated with diagnostic catheterization. Most of the NF were small in diameter (<10mm in 91.53%). Short-term improvement in PWI were demonstrated by normalized timing parameters (TTP and MTT).

APA, Harvard, Vancouver, ISO, and other styles

47

MORMINA, ENRICOMARIA. "Fusione di tecniche Angio-RM TOF-3D e Cisternografia-RM BALANCE-3D nella programmazione di terapia endovascolare d’urgenza in Pazienti affetti da Stroke ischemico acuto. Vedere oltre gli ostacoli." Doctoral thesis, 2020. http://hdl.handle.net/11570/3179583.

Full text

Abstract:

Introduzione: La patologia ischemica acuta cerebrale presenta in Italia una incidenza pari a 144-293/100.000/anno, costituendo la seconda causa di morte e la terza causa di disabilità a livello mondiale. Il trattamento riperfusivo per la rimozione dell’ostruzione trombotica arteriosa, attraverso somministrazione di terapia medica endovenosa o attraverso terapia endovascolare (EVT), presenta forti livelli di evidenza nel ridurre la mortalità ed il grado di disabilità in Pazienti affetti da stroke ischemico, ed è un trattamento tempo-dipendente. La selezione del Paziente per EVT può essere eseguita con TC ed Angio-TC, oppure con RM. Nel nostro centro il metodo utilizzato per la selezione del Paziente per EVT è la RM, che presenta elevata sensibilità e specificità nella selezione del Paziente (DWI-EPI, Angio-RM TOF-3D, FLAIR). Scopo dello Studio: Intento del nostro studio è dimostrare come l’aggiunta di una sequenza RM cisternografica, di breve durata B_FFE (BALANCED_FAST FIELD ECHO), fusa con sequenza Angio-RM TOF-3D possa influenzare la durata della EVT, grazie alla possibilità di una migliore definizione del setting anatomico a valle dell’ostruzione trombotica, che determinerebbe una più celere riperfusione. Materiali e Metodi: Su 215 Pazienti consecutivi, sono stati arruolati 40 Pazienti che potevano eseguire RM ed erano eleggibili ad EVT. 20 Pazienti sono stati randomicamente inseriti nel gruppo che ha eseguito B_FFE e fusione con Angio-RM TOF-3D, 20 Pazienti nel gruppo controllo (senza sequenza aggiuntiva). Risultati: Il gruppo di Pazienti con B_FFE e fusione Angio-RM TOF-3D (40%m, 60%f; età 78,8± 9,46) presentava tempi ridotti di EVT (p=0,036) rispetto al gruppo controllo (40%m, 60%f; età 76,9± 9,54). Non vi erano differenze significative tra gruppi per NIHSS al ricovero (p=0,14) ed alle dimissioni (p=0,09), mRS pre-stroke (p=0,26), ASPECT (p=0,36), ASPECT-DWI (p=0,15), tecnica EVT (p=0,47), successo riperfusivo (p=0,28), tempo in sala magnete (p=0,3), tempo intercorso tra esordio sintomi ed EVT (p=0,42). Conclusioni: L’aggiunta di una sequenza cisternografica-RM di breve durata, grazie ad una valutazione del setting anatomico a valle dell’ostruzione (riconoscimento di angoli, curve, biforcazioni, calibro, varianti anatomiche) influisce sul tempo di EVT. Il valore dell’aggiunta di detta sequenza, utile nella riduzione del tempo di EVT, sembrerebbe inoltre risiedere nella modificazione dell’approccio durante il planning pre- ed intra-EVT (ad es. scelta del materiale, curvatura delle microguide).

APA, Harvard, Vancouver, ISO, and other styles

48

Amelung, Nadine. "Evaluation intrakranieller In-Stent-Restenosen nach Stenting mit Hilfe digitaler Subtraktionsangiographie, Flachdetektor-CT und Multidetekor-CT." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3F0A-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Elahi, Furqan. "Medical equipment planning and construction of a interventional neuroradiology suite." Thesis, 2006. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2006-001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Lück, Nils [Verfasser]. "Magnetische versus manuelle Navigation in der interventionellen Neuroradiologie : In-vitro-Ergebnisse / vorgelegt von Nils Lück." 2009. http://d-nb.info/994253923/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Neuroradiologia'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles