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Letteratura scientifica selezionata sul tema "Oxygenation imaging"

Autore: Grafiati

Pubblicato: 26 ottobre 2023

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Articoli di riviste sul tema "Oxygenation imaging"

Costantino, ML, e GB Fiore. "Normalization of experimental results with respect to inlet conditions in membrane oxygenator testing". Perfusion 11, n. 1 (gennaio 1996): 45–51. http://dx.doi.org/10.1177/026765919601100106.

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This study looked at the problem of the excessive variability in oxygenator testing results, induced by variation of inlet parameters, particularly of inlet oxyhaemoglobin saturation. The investigation was carried out in the laboratory. An in vitro circuit was used to perfuse a small oxygenating cell. Blood flow rate (BFR) and film thickness (BFT) were varied to obtain different oxygenation conditions, while the inspired oxygen fraction (FiO 2) and ventilation ratio were kept at constant values. With each test condition, inlet saturation was varied in the range 60-70% and a number of veno-arterial blood samples (at least 20) were withdrawn and analysed for numerical computing and statistical analysis. The generic law relating oxygenation increment to inlet saturation was found. This allowed a useful normalization procedure to be applied to oxygenator testing results and render them comparable, even if obtained at different inlet conditions.

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Padhani, Anwar R., Kenneth A. Krohn, Jason S. Lewis e Markus Alber. "Imaging oxygenation of human tumours". European Radiology 17, n. 4 (17 ottobre 2006): 861–72. http://dx.doi.org/10.1007/s00330-006-0431-y.

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Benaron, David A., Susan R. Hintz, Arno Villringer, David Boas, Andreas Kleinschmidt, Jens Frahm, Christina Hirth et al. "Noninvasive Functional Imaging of Human Brain Using Light". Journal of Cerebral Blood Flow & Metabolism 20, n. 3 (marzo 2000): 469–77. http://dx.doi.org/10.1097/00004647-200003000-00005.

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Analysis of photon transit time for low-power light passing into the head, and through both skull and brain, of human subjects allowed for tomographic imaging of cerebral hemoglobin oxygenation based on photon diffusion theory. In healthy adults, imaging of changes in hemoglobin saturation during hand movement revealed focal, contralateral increases in motor cortex oxygenation with spatial agreement to activation maps determined by functional magnetic resonance imaging; in ill neonates, imaging of hemoglobin saturation revealed focal regions of low oxygenation after acute stroke, with spatial overlap to injury location determined by computed tomography scan. Because such slow optical changes occur over seconds and co-localize with magnetic resonance imaging vascular signals whereas fast activation-related optical changes occur over milliseconds and co-localize with EEG electrical signals, optical methods offer a single modality for exploring the spatio-temporal relationship between electrical and vascular responses in the brain in vivo, as well as for mapping cortical activation and oxygenation at the bedside in real-time for clinical monitoring.

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Kirkham, Brooke M., Susan M. Schultz, Khalid Ashi e Chandra M. Sehgal. "Assessment of Age-related Oxygenation Changes in Calf Skeletal Muscle by Photoacoustic Imaging: A Potential Tool for Peripheral Arterial Disease". Ultrasonic Imaging 41, n. 5 (19 luglio 2019): 290–300. http://dx.doi.org/10.1177/0161734619862287.

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Peripheral artery disease is often asymptomatic, and various imaging and nonimaging techniques have been used for assessment and monitoring treatments. This study is designed to demonstrate the ability of photoacoustic imaging to noninvasively determine changes in tissue oxygenation that occur in mice’s hind limb skeletal muscle as they age. Mice from two age cohorts were scanned bilaterally with a pulsed laser. The photoacoustic signal was unmixed to generate a parametric map of estimated oxygen saturation and then overlaid on grayscale ultrasound images. Tissue oxygenation measured in young and old mice was compared. Photoacoustic imaging visually and quantitatively showed the decrease in skeletal muscle oxygenation that occurs with age. Percent tissue oxygenation decreased from 30.2% to 3.5% ( p < 0.05). This reduction corresponded to reduced fractional area of oxygenation, which decreased from 60.6% to 6.0% ( p < 0.05). The change in oxygenation capacity of the still active vascular regions was insignificant ( p > 0.05). Intrasubject, intra-, and interobserver comparisons showed low variability in measurements, exhibited by high regression and intraclass correlations exceeding 0.81 for all ages. The decrease in oxygenation detected by photoacoustic imaging paralleled the known oxygenation decrease observed in aging tissues, demonstrating that photoacoustic imaging can assess age-related changes in a mouse calf muscle. These intramuscular changes could potentially act as a strong diagnostic marker for peripheral artery disease. This study thus opens the doors for a novel, affordable, noninvasive method of evaluation free of radiation or exogenous material.

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Vivier, Pierre-Hugues, Pippa Storey, Hersh Chandarana, Akira Yamamoto, Kristopher Tantillo, Umer Khan, Jeff L. Zhang et al. "Renal Blood Oxygenation Level–Dependent Imaging". Investigative Radiology 48, n. 7 (luglio 2013): 501–8. http://dx.doi.org/10.1097/rli.0b013e3182823591.

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Cies, Jeffrey J., Wayne S. Moore, Nadji Giliam, Tracy Low, Daniel Marino, Jillian Deacon, Adela Enache e Arun Chopra. "Oxygenator impact on voriconazole in extracorporeal membrane oxygenation circuits". Perfusion 35, n. 6 (6 luglio 2020): 529–33. http://dx.doi.org/10.1177/0267659120937906.

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Introduction: To determine the oxygenator impact on alterations of voriconazole in a contemporary neonatal/pediatric (1/4 inch) and adolescent/adult (3/8 inch) extracorporeal membrane oxygenation circuit including the Quadrox-i® oxygenator. Methods: Simulated closed-loop extracorporeal membrane oxygenation circuits (1/4 and 3/8 inch) were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. In addition, 1/4- and 3/8-inch circuits were also prepared without an oxygenator in series. A one-time dose of voriconazole was administered into the circuits, and serial pre- and post-oxygenator concentrations were obtained at 5 minutes, 1, 2, 3, 4, 5, 6, and 24 hour time points. Voriconazole was also maintained in a glass vial and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation Results: For the 1/4-inch circuit, there was an approximate mean of 64-67% voriconazole loss with the oxygenator in series and mean of 15-20% voriconazole loss without an oxygenator in series at 24 hours. For the 3/8-inch circuit, there was an approximate mean of 44-51% voriconazole loss with the oxygenator in series and a mean of 8-12% voriconazole loss without an oxygenator in series at 24 hours. The reference voriconazole concentrations remained relatively constant during the entire study period demonstrating that the drug loss in each size of the extracorporeal membrane oxygenation circuit with or without an oxygenator was not a result of spontaneous drug degradation. Conclusion: This ex vivo investigation demonstrated substantial voriconazole loss within an extracorporeal membrane oxygenation circuit with an oxygenator in series with both sizes of the Quadrox-i oxygenator at 24 hours and no significant voriconazole loss in the absence of an oxygenator. Further evaluations with multiple dose in vitro and in vivo investigations are needed before specific voriconazole dosing recommendations can be made for clinical application with extracorporeal membrane oxygenation.

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Ni, Wendy W., Thomas Christen, Jarrett Rosenberg, Zungho Zun, Michael E. Moseley e Greg Zaharchuk. "Imaging of cerebrovascular reserve and oxygenation in Moyamoya disease". Journal of Cerebral Blood Flow & Metabolism 37, n. 4 (20 luglio 2016): 1213–22. http://dx.doi.org/10.1177/0271678x16651088.

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This study aimed to determine whether measurements of cerebrovascular reserve and oxygenation, assessed with spin relaxation rate R2′, yield similar information about pathology in pre-operative Moyamoya disease patients, and to assess whether R2′ is a better measure of oxygenation than other proposed markers, such as R2* and R2. Twenty-five pre-operative Moyamoya disease patients were scanned at 3.0T with acetazolamide challenge. Cerebral blood flow mapping with multi-delay arterial spin labeling, and R2*, R2, and R2′ mapping with Gradient-Echo Sampling of Free Induction Decay and Echo were performed. No baseline cerebral blood flow difference was found between angiographically abnormal and normal regions (49 ± 12 vs. 48 ± 11 mL/100 g/min, p = 0.44). However, baseline R2′ differed between these regions (3.2 ± 0.7 vs. 2.9 ± 0.6 s−1, p < 0.001), indicating reduced oxygenation in abnormal regions. Cerebrovascular reserve was lower in angiographically abnormal regions (21 ± 38 vs. 41 ± 26%, p = 0.001). All regions showed trend toward significantly improved oxygenation post-acetazolamide. Regions with poorer cerebrovascular reserve had lower baseline oxygenation (Kendall's τ = −0.24, p = 0.003). A number of angiographically abnormal regions demonstrated preserved cerebrovascular reserve, likely due to the presence of collaterals. Finally, of the concurrently measured relaxation rates, R2′ was superior for oxygenation assessment.

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Yamaleyeva, Liliya M., K. Bridget Brosnihan, Lane M. Smith e Yao Sun. "Preclinical Ultrasound-Guided Photoacoustic Imaging of the Placenta in Normal and Pathologic Pregnancy". Molecular Imaging 17 (1 gennaio 2018): 153601211880272. http://dx.doi.org/10.1177/1536012118802721.

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Placental oxygenation varies throughout pregnancy. The detection of early changes in placental oxygenation as pregnancy progresses is important for early identification of preeclampsia or other complications. This invited commentary discusses a recent preclinical study on the application of 3-dimensional photoacoustic imaging (PAI) for assessment of regional variations in placental oxygenation and longitudinal analysis of differences in placental oxygenation throughout normal pregnancy and pregnancy associated with hypertension or placental insufficiency in mice. Three-dimensional PAI more accurately reflects oxygen saturation, hemoglobin concentrations, and changes in oxygen saturation in whole placenta compared to 2-dimensional imaging. These studies suggest that PAI is a sensitive tool to detect different levels of oxygen saturation in the placental and fetal vasculature in pathologic and normal pregnancy in mice.

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Yang, Hsin-Jung, Ilkay Oksuz, Damini Dey, Jane Sykes, Michael Klein, John Butler, Michael S. Kovacs et al. "Accurate needle-free assessment of myocardial oxygenation for ischemic heart disease in canines using magnetic resonance imaging". Science Translational Medicine 11, n. 494 (29 maggio 2019): eaat4407. http://dx.doi.org/10.1126/scitranslmed.aat4407.

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Myocardial oxygenation—the ability of blood vessels to supply the heart muscle (myocardium) with oxygen—is a critical determinant of cardiac function. Impairment of myocardial oxygenation is a defining feature of ischemic heart disease (IHD), which is caused by pathological conditions that affect the blood vessels supplying oxygen to the heart muscle. Detecting altered myocardial oxygenation can help guide interventions and prevent acute life-threatening events such as heart attacks (myocardial infarction); however, current diagnosis of IHD relies on surrogate metrics and exogenous contrast agents for which many patients are contraindicated. An oxygenation-sensitive cardiac magnetic resonance imaging (CMR) approach used previously to demonstrate that CMR signals can be sensitized to changes in myocardial oxygenation showed limited ability to detect small changes in signals in the heart because of physiologic and imaging noise during data acquisition. Here, we demonstrate a CMR-based approach termed cfMRI [cardiac functional magnetic resonance imaging (MRI)] that detects myocardial oxygenation. cfMRI uses carbon dioxide for repeat interrogation of the functional capacity of the heart’s blood vessels via a fast MRI approach suitable for clinical adoption without limitations of key confounders (cardiac/respiratory motion and heart rate changes). This method integrates multiple whole-heart images within a computational framework to reduce noise, producing confidence maps of alterations in myocardial oxygenation. cfMRI permits noninvasive monitoring of myocardial oxygenation without requiring ionizing radiation, contrast agents, or needles. This has the potential to broaden our ability to noninvasively identify IHD and a diverse spectrum of heart diseases related to myocardial ischemia.

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Shahidi, Mahnaz, Norman P. Blair, Marek Mori e Ruth Zelkha. "Feasibility of Noninvasive Imaging of Chorioretinal Oxygenation". Ophthalmic Surgery, Lasers and Imaging Retina 35, n. 5 (1 settembre 2004): 415–22. http://dx.doi.org/10.3928/1542-8877-20040901-10.

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Tesi sul tema "Oxygenation imaging"

Huang, Jiwei. "Multispectral Imaging of Skin Oxygenation". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1356637098.

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Sivaramakrishnan, Mathangi. "In vivo blood oxygenation level measurements using photoacoustic microscopy". Texas A&M University, 2003. http://hdl.handle.net/1969.1/5851.

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We investigate the possibility of extracting accurate functional information such as local blood oxygenation level using multi-wavelength photoacoustic measurements. Photoacoustic microscope is utilized to acquire images of microvasculature in smallanimal skin. Owing to endogenous optical contrast, optical spectral information obtained from spectral photoacoustic measurements are successfully inverted to yield oxygenation level in blood. Analysis of error propagation from photoacoustic measurements to inverted quantities showed minimum inversion error in the optical wavelength region of 570-600 nm. To obtain accurate and vessel size independent blood oxygenation measurements, transducers with central frequency of more than 25 MHz are needed for the optical region of 570-600 nm used in this study. The effect of transducer focal position on accuracy of blood oxygenation level quantification was found to be negligible. To obtain accurate measurements in vivo, one needs to compensate for factors such as spectral dependent optical attenuation.

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Lidegran, Marika. "Advanced radiological imaging in patients treated with extracorporeal membrane oxygenation /". Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-933-5/.

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Chen, T. "Hyperspectral imaging for the remote sensing of blood oxygenation and emotions". Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7502.

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This PhD project is a basic research and it concerns with how human’s physiological features, such as tissue oxygen saturation (StO2), can be captured from a stand-off distance and then to understand how this remotely acquired physiological feature can be deployed for biomedical and other applications. This work utilises Hyperspectral Imaging (HSI) within the diffuse optical scattering framework, to assess the StO2 in a contactless remote sensing manner. The assessment involves a detailed investigation about the wavelength dependence of diffuse optical scattering from the skin as well as body tissues, under various forms of optical absorption models. It is concluded that the threechromophore extended Beer Lambert Law model is better suited for assessing the palm and facial tissue oxygenations, especially when spectral data in the wavelengths region of [516-580]nm is used for the analysis. A first attempt of using the facial StO2 to detect and to classify people’s emotional state is initiated in this project. The objective of this work is to understand how strong emotions, such as distress that caused by mental or physical stimulations, can be detected using physiological feature such as StO2. Based on data collected from ~20 participants, it is found that the forehead StO2 is elevated upon the onset of strong emotions that triggered by mental stimulation. The StO2 pattern in the facial region upon strong emotions that are initiated by physical stimulations is quite complicated, and further work is needed for a better understanding of the interplays between bodily physique, individual’s health condition and blood transfusion control mechanism. Most of this work has already been published and future research to follow up when the author returns back to China is highlighted.

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Tomaszewski, Michal Robert. "Functional imaging of cancer using Optoacoustic Tomography". Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/284931.

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Poor oxygenation of solid tumours has been linked with resistance to chemo- and radio-therapy and poor patient outcomes. Measuring the functional status of the tumour vasculature, including blood flow fluctuations and changes in oxygenation is important in cancer staging and therapy monitoring. A robust method is needed for clinical non-invasive measurement of the oxygen supply and demand in tumours. Current clinically approved imaging modalities suffer high cost, long procedure times and limited spatio-temporal resolution. Optoacoustic tomography (OT) is an emerging clinical imaging modality that can provide static images of endogenous haemoglobin concentration and oxygenation. In this work, an integrated framework for quantitative analysis of functional imaging using OT is developed and applied in vivo with preclinical cancer models. Oxygen Enhanced (OE)-OT is established here to provide insight into tumour vascular function and oxygen availability in the tissue. Tracking oxygenation dynamics using OE-OT reveals significant differences between two prostate cancer models in nude mice with markedly different vascular function (PC3 & LNCaP), which appear identical in static OT. OE-OT metrics are shown to be highly repeatable and correlate directly on a per-tumour basis to tumour vascular maturity, hypoxia and necrosis, assessed ex vivo. Dynamic Contrast Enhanced (DCE) OT demonstrates the relationship between OE-OT response and tumour perfusion in vivo. Finally, the possibility of using OT data acquired at longer wavelengths to report on tumour water and lipid content is investigated, with a view to future providing intrinsically co-registered imaging of tumour oxygenation and cellular necrosis. These findings indicate that OE-OT holds potential for application in prostate cancer patients, to improve delineation of aggressive and indolent disease, while combined with DCE-OT, it may offer significant advantage for localised imaging of tumour response to vascular targeted therapies. Further work is needed to establish whether OT can provide a new method to detect tumour necrosis in vivo.

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Alonzi, Roberto. "Evaluation of the oxygenation and vascularity of prostate cancer using magnetic resonance imaging". Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1444256/.

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The outcome of radical treatment for prostate cancer is appreciably influenced by the presence of hypoxia. Oxygenation status may therefore be another underlying biological parameter, beyond the classic prognostic factors (age, clinical stage, Gleason score and prostate specific antigen), that predicts for treatment failure in this malignancy. Angiogenesis plays a pivotal role in the growth, invasion, metastasis and survival of prostate tumours. Measurements of angiogenesis have been linked with clinical and pathological stage, histological grade and the potential for metastasis formation. They also provide prognostic information and have been correlated with disease-specific survival and progression after treatment. Magnetic resonance imaging techniques are capable of detecting the molecular, biochemical, physiological and metabolic changes that occur due to pathological processes within tissues. Experiments presented in this thesis have sought to evaluate the ability of Dynamic Contrast Enhanced MRI (DCE-MRI), Dynamic Susceptibility Contrast MRI (DSC-MRI), Intrinsic Susceptibility Weighted MRI (also known as Blood Oxygen Level Dependent (BOLD) MRI) and Diffusion Weighted Imaging (DWI) to characterise the oxygenation and vascular status of prostate tumours in animal models and in patients with prostate cancer. This research has demonstrated the feasibility of hypoxia imaging in prostate cancer. Although MRI can not precisely map tissue p02, the combination of BOLD-MRI and dynamic susceptibility contrast MRI provides a valuable surrogate and predicts the pattern of hypoxia, as determined by pimonidazole immunohistochemistry, with reasonable accuracy. The research has also shown that prostate cancer responds to carbogen gas breathing and that androgen deprivation causes profound vascular collapse within one month of starting therapy. These findings should help in the rational design of future studies that aim to target tumour vasculature and combat tumour hypoxia in prostate cancer.

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Fan, Audrey Peiwen. "Development, testing, and application of quantitative oxygenation imaging from magnetic susceptibility by MRI". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/89990.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 101-133).
The healthy brain consumes 20% of total oxygen used by the body under normal conditions. Continuous oxygen delivery to neural tissue is needed to maintain normal brain function and viability. Reliable measurements of brain oxygenation can provide critical information to diagnose and manage diseases in which this oxygen supply is disturbed, including stroke and tumor. In acute stroke, for instance, metabolic biomarkers such as local oxygen extraction fraction (OEF) have been shown to identify tissue at risk of infarction by positron emission tomography. This knowledge can then be used to identify patients who are candidates for reperfusion therapies or to avoid thrombolytic therapy in futile situations. Unfortunately, there is currently no clinically feasible method for radiologists to assess brain oxygenation in patients. My thesis aims to address this need through development of a clinically viable tool to examine regional OEF in the brain with magnetic resonance imaging (MRI). We have designed a novel imaging and analysis method to quantify oxygenation in cerebral veins. MRI phase images are sensitive to local, oxygenation-dependent magnetic field variations in brain vessels, due to the presence of paramagnetic deoxyhemoglobin molecules in venous blood. Our method was developed on a 3 Tesla MRI scanner and tested in 10 healthy volunteers during hypercapnia, i.e. breathing of low levels of CO₂. This respiratory challenge changes the baseline oxygenation state of the brain, enabling us to test whether our MRI method can detect different levels of OEF in vivo. We also show that OEF is reduced in 23 patients with multiple sclerosis, an autoimmune disease of the central nervous disease, and relates to their performance on cognitive tasks.
by Audrey P. Fan.
Ph. D.

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Huen, Isaac Kwong-Ping. "Assessment of placental and fetal oxygenation in normal and abnormal pregnancy using magnetic resonance imaging". Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/assessment-of-placental-and-fetal-oxygenation-in-normal-and-abnormal-pregnancy-using-magnetic-resonance-imaging(8cd3f9a2-22cb-4c95-bee3-06b5c4bfc2d2).html.

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Fetal growth restriction (FGR) is a common pregnancy complication resulting in increased neonatal mortality and morbidity. The aetiology of fetal growth restriction is not fully understood, but abnormalities in placental development are, leading to abnormalities in placental structure which are thought to affect supply of oxygen to the fetus. The source of fetal hypoxia is unknown due to the difficulty in obtaining oxygenation data in the context of pregnancy using existing techniques. There is also an absence of data relating to oxygenation in FGR pregnancies. Oxygen-Enhanced MRI (OE-MRI) and Blood Oxygen-Level Dependent (BOLD) MRI permit noninvasive acquisition of data related to changes in the concentration of dissolved oxygen (pO2) and changes in hemoglobin saturation (sO2) under air- and oxygen- breathing (hyperoxic challenge).The aim of this project was to determine whether MRI methods can provide information relating to placental oxygenation in normal and FGR-compromised pregnancy, to investigate fetal brain oxygenation and to assess the potential confound of placental perfusion changes under hyperoxic challenge. After optimization of sequences in non-pregnant volunteers, similar pO2 and sO2 increases under hyperoxic challenge were seen in normal and FGR pregnancy. This suggested placental oxygenation was similar and that fetal extraction of oxygen may be a likelier cause of fetal hypoxia. Normal fetal brain oxygenation was found not to increase under hyperoxic challenge, which may be due to hemodynamic adaptation to limit cerebral hyperoxygenation. Finally, the robustness of these oxygenation results was supported by the lack of placental perfusion changes observed under hyperoxia using Arterial Spin Labeling (ASL).In conclusion, MRI methods successfully provided information on placental and fetal oxygenation in normal and abnormal pregnancy, obtaining novel data informing the aetiology of FGR and the physiology of the fetal brain.

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Schafer, Rachel Lynn. "Mammary Window Chamber Model: A Platform For Multi-Modality Cancer Imaging And Dynamic Oxygenation Assessment". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/556436.

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Window chamber models have served as a tool for optically visualizing a tissue environment over time. Their use throughout the years has furthered the study of cancer. However, optical imaging techniques utilized with the model are limited in the depth from which light can penetrate and signal can be received. Further, ectopic placement of a xenograft in a model animal may modify the relevancy of findings by altering the normal environmental conditions. In the first section of the dissertation, improvements on the traditional window chamber model are described in the context of enabling multiple imaging modalities (optical, MR and nuclear) to be complementarily applied. The developed model, specifically geared toward breast cancer, is orthotopic and supports uninhibited tumor growth into the body of the animal. The three main imaging modalities applied provide unique strengths in obtaining information from the model system. Optical imaging allows for use of targeted fluorescent contrast agents, as well as sufficient resolution to visualize individual cells and capillaries. Magnetic resonance imaging provides the possibility of acquiring quantitative information about tumor morphology as well as a variety of physiological processes. This can be accomplished over the entire 3D volume of the tumor. Nuclear imaging provides functional and/or metabolic information using radiolabeled agents. The MWC model provides a platform for more specifically focused cancer imaging approaches to be applied and tested. The presence of hypoxia in tumors has a broad impact on cancer development and treatment. Current oxygenation assessment methods for longitudinally following spatially resolved oxygen changes over time are lacking. The development and testing of an oxygen sensitive porphyrin coating used in conjunction with the mammary window chamber model is detailed in the second section of the dissertation. Three different modulations were applied to induce physiologic oxygenation changes. All were capable of being detected over time utilizing a phosphorescence lifetime approach. An assessment of the stability of the coating found the coating remained suitable for a minimum of one week. The oxygen dependent phosphorescence lifetime of the coating was determined to be worthwhile for temporally and spatially monitoring oxygen changes of the tissue in contact with the surface of the coating. The third section of this dissertation work utilized the developed window chamber and oxygen measurement technique to investigate a novel oxygen modulator. The effectiveness of radiation therapy is reduced in tumors with low oxygen. The drug, NVX-108, is under investigation as a means to increase oxygenation prior to radiation treatment. NVX-108 is given while the patient breaths carbogen and has not been thoroughly tested when the patient is breathing oxygen or air. The study described herein focused on measuring the increase in oxygenation when NVX-108 was delivered while an anesthetized mouse breathed carbogen, oxygen or air. A similar average increase was measured under carbogen and oxygen breathing at two dosage levels of NVX-108. The increase was higher than with air breathing conditions. Additional animal experiments are needed in order to obtain a statistically significant finding.

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Hu, Qiuhua. "Investigating prostate tumour vasculature and oxygenation status in response to androgen-targeted therapies using photoacoustic-ultrasound imaging". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/228679/8/Qiuhua_Hu_Thesis.pdf.

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This project provides a holistic view of changes in the prostate cancer microenvironment in response to androgen targeted therapies. Oxygen saturation and total haemoglobin were monitored using the ultrasound and photoacoustic imaging capabilities of the VEVO LAZR system (FUJIFILM Visual Sonics Inc) and compared with measuring hypoxic and vascular markers using conventional protein and gene expression techniques. Understanding the effects of castration and enzalutamide on the vasculature and oxygenation status of prostate cancer subcutaneous xenografts has the potential to reveal novel mechanisms of therapy resistance and may improve the prediction of patient therapy responses.

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Più fonti

Libri sul tema "Oxygenation imaging"

Kipnis, Eric, e Benoit Vallet. Tissue perfusion monitoring in the ICU. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0138.

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Resuscitation endpoints have shifted away from restoring normal values of routinely assessed haemodynamic parameters (central venous pressure, mean arterial pressure, cardiac output) towards optimizing parameters that reflect adequate tissue perfusion. Tissue perfusion-based endpoints have changed outcomes, particularly in sepsis. Tissue perfusion can be explored by monitoring the end result of perfusion, namely tissue oxygenation, metabolic markers, and tissue blood flow. Tissue oxygenation can be directly monitored locally through invasive electrodes or non-invasively using light absorbance (pulse oximetry (SpO2) or tissue (StO2)). Global oxygenation may be monitored in blood, either intermittently through blood gas analysis, or continuously with specialized catheters. Central venous saturation (ScvO2) indirectly assesses tissue oxygenation as the net balance between global O2 delivery and uptake, decreasing when delivery does not meet demand. Lactate, a by-product of anaerobic glycolysis, increases when oxygenation is inadequate, and can be measured either globally in blood, or locally in tissues by microdialysis. Likewise, CO2 (a by-product of cellular respiration) and PCO2 can be measured globally in blood or locally in accessible mucosal tissues (sublingual, gastric) by capnography or tonometry. Increasing PCO2 gradients, either tissue-to-arterial or venous-to-arterial, are due to inadequate perfusion. Metabolically, the oxidoreductive status of mitochondria can be assessed locally through NADH fluorescence, which increases in situations of inadequate oxygenation/perfusion. Finally, local tissue blood flow may be measured by laser-Doppler or visualized through intravital microscopic imaging. These perfusion/oxygenation resuscitation endpoints are increasingly used and studied in critical care.

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Mavi, Jagroop, Anne C. Boat, Senthilkumar Sadhasivam e Catherine P. Seipel. Congenital Diaphragmatic Hernia Repair. A cura di Erin S. Williams, Olutoyin A. Olutoye, Catherine P. Seipel e Titilopemi A. O. Aina. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190678333.003.0050.

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Congenital diaphragmatic hernia is an embryologic defect in diaphragm formation that allows abdominal contents to enter into the fetal pleural cavity, resulting in ipsilateral lung compression, pulmonary hypoplasia, and abnormal pulmonary vasculature. Though diagnosis is frequently made on prenatal imaging, the diagnosis should be considered in any newborn with respiratory distress. Prenatal predictors of defect severity include evaluation of observed-to-expected lung volumes on fetal magnetic resonance imaging and lung-to-head ratio on fetal ultrasound. Treatment focuses on medical stabilization, including optimization of oxygenation and ventilation, followed by surgical repair. Anesthetic considerations for these patients include management of coexisting cardiac disease and ventilatory parameters, in addition to standard neonatal anesthetic considerations.

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Gaddam, Samson Sujit Kumar, e Claudia S. Robertson. Cerebral blood flow and perfusion monitoring in the critically ill. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0222.

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Prevention of secondary cerebral ischaemic insults is an important management strategy in acute neurological conditions. Monitoring of cerebral perfusion may aid in early identification of ischaemic insults and help with management. A number of tools are available for this purpose. Cerebral perfusion pressure (CPP) is the simplest assessment of cerebral perfusion, but in some cases ischaemia can be present even with a normal CPP. Cerebral blood flow (CBF) imaging, either with computed tomography or magnetic resonance imaging techniques, can provide quantitative regional CBF measurement, but only at a single instance in time. Such studies are valuable in the diagnosis of ischaemia, but are difficult for the management of critically-ill patients. CBF can also be measured within the intensive care unit (ICU), either directly or indirectly through the measurement of cerebral oxygenation. These monitors provide a more continuous measure of CBF, and are more useful in assessing response to treatment. Some of the ICU tools monitor global perfusion and some assess perfusion only in a local area of brain surrounding the monitor. With local monitors, the location of the probe is important for interpretation of the findings.

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Capitoli di libri sul tema "Oxygenation imaging"

Zhou, Heling, Nuria Arias-Ramos, Pilar López-Larrubia, Ralph P. Mason, Sebastián Cerdán e Jesús Pacheco-Torres. "Oxygenation Imaging by Nuclear Magnetic Resonance Methods". In Preclinical MRI, 297–313. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-7531-0_18.

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Li, Lu-Ping, e Pottumarthi V. Prasad. "Estimation of Kidney Oxygenation by Blood Oxygenation Level Dependent Magnetic Resonance Imaging". In Studies on Renal Disorders, 587–609. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-857-7_30.

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Wilson, David F., e George J. Cerniglia. "Oxygenation of Tumors as Evaluated by Phosphorescence Imaging". In Advances in Experimental Medicine and Biology, 539–47. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2468-7_72.

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Li, Baowang, e Ralph D. Freeman. "Noninvasive Neural Imaging and Tissue Oxygenation in the Visual System". In Neurovascular Coupling Methods, 97–122. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-0724-3_6.

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Benaron, David A., e David K. Stevenson. "Resolution of Near Infrared Time-of-Flight Brain Oxygenation Imaging". In Advances in Experimental Medicine and Biology, 609–17. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2468-7_81.

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Lazzeroni, Marta, Hatice Bunea, Anca L. Grosu, Dimos Baltas, Iuliana Toma-Dasu e Alexandru Dasu. "Mathematical Description of Changes in Tumour Oxygenation from Repeated Functional Imaging". In Advances in Experimental Medicine and Biology, 195–200. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-91287-5_31.

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Arridge, S. R., M. Cope, P. Van Der Zee, P. J. Hillson e D. T. Delpy. "Visualization of the Oxygenation State of Brain and Muscle in Newborn Infants by Near Infra-Red Transillumination". In Information Processing in Medical Imaging, 155–76. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4261-5_12.

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Takahashi, Eiji, e Katsuhiko Doi. "Digital Imaging of The Oxygenation State within an Isolated Single Rat Cardiomyocyte". In Advances in Experimental Medicine and Biology, 163–69. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-1875-4_21.

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Carlier, P. G. "Skeletal Muscle Perfusion and Oxygenation Assessed by Dynamic NMR Imaging and Spectroscopy". In Oxygen Transport to Tissue XXXII, 341–46. Boston, MA: Springer US, 2011. http://dx.doi.org/10.1007/978-1-4419-7756-4_46.

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Howe, Franklyn A., Simon P. Robinson, Loreta M. Rodrigues, Marion Stubbs e John R. Griffiths. "Issues in GRE & Se Magnetic Resonance Imaging to Probe Tumor Oxygenation". In Oxygen Transport to Tissue XXIV, 441–48. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4615-0075-9_41.

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Atti di convegni sul tema "Oxygenation imaging"

Cong, Wenxiang, Durairaj Kumar, Alexander Cong e Ge Wang. "Spectroscopic luminescent tomographic imaging for quantitative assessment of hemoglobin oxygenation". In Medical Imaging, a cura di Michael J. Flynn. SPIE, 2005. http://dx.doi.org/10.1117/12.595427.

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Busch, David R., Genevieve Du Pont-Thibodeau, Constantine D. Mavroudis, Ann L. McCarthy, Tiffany Ko, Madeline E. Winters, John J. Newland et al. "Cerebral Autoregulation During Pediatric Extracorporeal Membrane Oxygenation Therapy". In Cancer Imaging and Therapy. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/cancer.2016.jtu3a.49.

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Ferrer Ortas, Júlia, Pierre Mahou, Sophie Escot, Chiara Stringari, Nicolas B. David, Laure Bally-Cuif, Nicolas Dray, Michel Négrerie, Willy Supatto e Emmanuel Beaurepaire. "Color TSFG microscopy of red blood cells and oxygenation". In Advances in Microscopic Imaging, a cura di Emmanuel Beaurepaire, Adela Ben-Yakar e YongKeun Park. SPIE, 2023. http://dx.doi.org/10.1117/12.2670229.

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Chong, Shau Poh, Conrad William Merkle, Harsha Radhakrishnan, Conor Leahy, Alfredo Dubra, Yusufu N. Sulai e Vivek J. Srinivasan. "Optical Coherence Imaging of Microvascular Oxygenation and Hemodynamics". In CLEO: Applications and Technology. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/cleo_at.2014.ath1o.2.

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Dot, Audrey, Anne Planat-Chrétien, Mathieu Perriollat, Michel Berger, Rodolphe Lartizien, Maxime Henry, Georges Bettega e Jean-Luc Coll. "Blood oxygenation in buried flaps: a bi-layer reconstruction". In Diffuse Optical Spectroscopy and Imaging, a cura di Hamid Dehghani e Heidrun Wabnitz. SPIE, 2019. http://dx.doi.org/10.1117/12.2527176.

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Amendola, Caterina, Giacomo Cavallaro, Giacomo Amelio, Livia Provitera, Genny Raffaeli, Fabio Mosca, Lorenzo Spinelli, Alessandro M. Torricelli e Davide Contini. "Cerebral hemodynamics monitoring during extracorporeal membrane oxygenation in piglets". In Diffuse Optical Spectroscopy and Imaging, a cura di Davide Contini, Yoko Hoshi e Thomas D. O'Sullivan. SPIE, 2023. http://dx.doi.org/10.1117/12.2670871.

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Delpy, D. T. "Optical Imaging in Medicine". In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.cmd1.

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Abstract (sommario):

Optical spectroscopy is a routinely used clinical laboratory technique, and since the 1930’s has been used to examine tissue oxygenation in thin tissue sections or from surface reflection measurements. However, in the 1970’s the technique of near infrared spectroscopy (NIRS) of intact organs was first described by Frans Jobsis, a breakthrough that enabled truly non invasive measurements to be made on intact organs, allowing the technique to be applied to patients at the bedside. In the NIR (700-900 nm), oxygenation dependent changes in attenuation can be observed which arise from variations in the concentration of oxy and deoxyhaemoglobin in the blood, and of oxidised cytochrome oxidase in the cell mitochondria. Since the initial report of Jobsis, instrumental improvements now enable us to measure attenuation changes across many centimetres of tissue (most commonly brain or muscle), and techniques to quantify haemodynamic variables such as blood flow and volume have been developed.

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Agarwal, Shubhangi, Rohini Vidya Shankar, Landon J. Inge e Vikram Kodibagkar. "MRI assessment of changes in tumor oxygenation post hypoxia-targeted therapy". In SPIE Medical Imaging, a cura di Barjor Gimi e Robert C. Molthen. SPIE, 2015. http://dx.doi.org/10.1117/12.2083926.

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Kirchner, Thomas, Janek Gröhl, Niklas Holzwarth, Mildred A. Herrera, Adrián Hernández-Aguilera, Edgar Santos e Lena Maier-Hein. "Photoacoustic monitoring of blood oxygenation during neurosurgical interventions". In Photons Plus Ultrasound: Imaging and Sensing 2019, a cura di Alexander A. Oraevsky e Lihong V. Wang. SPIE, 2019. http://dx.doi.org/10.1117/12.2509608.

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Hintz, Susan R., David A. Benaron, Robert Robbins, Joshua L. Duckworth, Aileen L. Murphy, John W. Price, Frank W. H. Liu, David K. Stevenson e Wai-Fung Cheong. "Monitoring Brain Oxygenation Using Time-of-Flight Spectroscopy". In Advances in Optical Imaging and Photon Migration. Washington, D.C.: OSA, 1998. http://dx.doi.org/10.1364/aoipm.1998.asub4.

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Rapporti di organizzazioni sul tema "Oxygenation imaging"

Shafiiha, Roshanak. Combined MR and Optical Imaging System for Noninvasive Tumor Characterization and Quantification of Oxygenation Gain Factor in a Breast Cancer Animal Model. Fort Belvoir, VA: Defense Technical Information Center, giugno 2007. http://dx.doi.org/10.21236/ada472342.

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