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Bell, Tyler M., Petra Klein, Norman Wildmann, and Robert Menke. "Analysis of flow in complex terrain using multi-Doppler lidar retrievals." Atmospheric Measurement Techniques 13, no. 3 (2020): 1357–71. http://dx.doi.org/10.5194/amt-13-1357-2020.
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Abstract. Strategically placed Doppler lidars (DLs) offer insights into flow processes that are not observable with meteorological towers. For this study we use intersecting range height indicator (RHI) scans of scanning DLs to create four virtual towers. The measurements were performed during the Perdigão experiment, which set out to study atmospheric flows in complex terrain and to collect a high-quality dataset for the validation of meso- and microscale models. Here we focus on a period of 6 weeks from 1 May 2017 through 15 June 2017. During this Intensive Observation Period (IOP) data of six intersecting RHI scans are used to calculate wind speeds at four virtual towers located along the valley at Perdigão with a temporal resolution of 15 min. While meteorological towers were only up to 100 m tall, the virtual towers cover heights from 50 to 600 m above the valley floor. Thus, they give additional insights into the complex interactions between the flow inside the valley and higher up across the ridges. Along with the wind speed and direction, uncertainties of the virtual-tower retrieval were analyzed. A case study of a nighttime stable boundary layer flow with wave features in the valley is presented to illustrate the usefulness of the virtual towers in analyzing the spatially complex flow over the ridges during the Perdigão campaign. This study shows that, despite having uncoordinated scans, the retrieved virtual towers add value in observing flow in and above the valley. Additionally, the results show the virtual towers can more accurately capture the flow in areas where the assumptions for more traditional DL scan strategies break down.
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Higashihira, Shota, Naomi Kobayashi, Hyonmin Choe, Kosuke Sumi, and Yutaka Inaba. "Use of a 3D Virtually Reconstructed Patient-Specific Model to Examine the Effect of Acetabular Labral Interference on Hip Range of Motion." Orthopaedic Journal of Sports Medicine 8, no. 11 (2020): 232596712096446. http://dx.doi.org/10.1177/2325967120964465.
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Background: The labrum is likely to influence impingement, which may also depend on acetabular coverage. Simulating impingement using 3-dimensional (3D) computed tomography (CT) is a potential solution to evaluating range of motion (ROM); however, it is based on bony structures rather than on soft tissue. Purpose: To examine ROM when the labrum is considered in a 3D dynamic simulation. A particular focus was evaluation of maximum flexion and internal rotation angles before occurrence of impingement, comparing them in cases of cam-type femoroacetabular impingement (FAI) and borderline developmental dysplasia of the hip (BDDH). Study Design: Descriptive laboratory study. Methods: Magnetic resonance imaging (MRI) and CT scans of 40 hips (20 with cam-type FAI and 20 with BDDH) were reviewed retrospectively. The thickness and width of the labrum were measured on MRI scans. A virtual labrum was reconstructed based on patient-specific sizes measured on MRI scans. The impingement point was identified using 3D dynamic simulation and was compared with the internal rotation angle before and after labral reconstruction. Results: The thickness and width of the labrum were significantly larger in BDDH than in FAI ( P < .001). In FAI, the maximum internal rotation angles without the labrum were 30.3° at 90° of flexion and 56.9° at 45° of flexion, with these values decreasing to 18.7° and 41.4°, respectively, after labral reconstruction ( P < .001). In BDDH, the maximum internal rotation angles were 48.0° at 90° of flexion and 76.7° at 45° of flexion without the labrum, decreasing to 31.1° and 55.3°, respectively, after labral reconstruction ( P < .001). The differences in the angles before and after labral reconstruction were larger in BDDH than in FAI (90° of flexion, P = .03; 45° of flexion, P = .01). Conclusion: As the labrum was significantly more hypertrophic in BDDH than in FAI, the virtual labral model revealed that the labrum’s interference with the maximum internal rotation angle was also significantly larger in BDDH. Clinical Relevance: The labrum has a significant effect on impingement; this is more significant for BDDH than for FAI.
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Moreau, Jean-David, Peter Cloetens, Bernard Gomez, et al. "Multiscale 3D Virtual Dissections of 100-Million-Year-Old Flowers Using X-Ray Synchrotron Micro- and Nanotomography." Microscopy and Microanalysis 20, no. 1 (2014): 305–12. http://dx.doi.org/10.1017/s1431927613014025.
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AbstractA multiscale approach combining phase-contrast X-ray micro- and nanotomography is applied for imaging a Cretaceous fossil inflorescence in the resolution range from 0.75 μm to 50 nm. The wide range of scale views provides three-dimensional reconstructions from the external gross morphology of the inflorescence fragment to the finest exine sculptures of in situ pollen. This approach enables most of the characteristics usually observed under light microscopy, or with low magnification under scanning and transmission electron microscopy, to be obtained nondestructively. In contrast to previous tomography studies of fossil and extant flowers that used resolutions down to the micron range, we used voxels with a 50 nm side in local tomography scans. This high level of resolution enables systematic affinities of fossil flowers to be established without breaking or slicing specimens.
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Moroder, Philipp, Fabian Plachel, Mark Tauber, et al. "Risk of Engagement of Bipolar Bone Defects in Posterior Shoulder Instability." American Journal of Sports Medicine 45, no. 12 (2017): 2835–39. http://dx.doi.org/10.1177/0363546517714456.
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Background: The risk of re-engagement of bipolar bone defects in posterior shoulder instability has not yet been investigated. Hypothesis: Posterior glenoid defects can lead to the engagement of supposedly noncritical reverse Hill-Sachs lesions (RHSLs). Study Design: Descriptive laboratory study. Methods: In a retrospective multicenter study, 102 cases of posterior shoulder dislocations and resulting RHSLs were collected. Of these cases, all patients with available computed tomography (CT) scans, with a reduced shoulder joint, and without bony posterior glenoid rim defects or concomitant dislocated fractures of the humeral head were included. The gamma angle (measure of the critical size and localization of RHSLs) and the delta angle (measure of the degree of internal rotation necessary for engagement to occur) of the RHSLs were determined on standardized CT scans. Virtual posterior glenoid defects were created, and the effect of increasing defect size on the delta angle was determined. Results: The mean gamma angle of the 19 patients included in this study was 94.5° (range, 69.7°-124.8°). After creation of the virtual posterior glenoid defects, a mean reduction of the delta angle by 2.3° ± 0.2° (range, 1.9°-2.9°) per millimeter defect was observed. The cumulative change in the delta angle showed a highly significant correlation with the absolute and relative size of the glenoid defect ( R = 0.982, P < .001 and R = 0.974, P < .001, respectively). Conclusion: Concomitant posterior glenoid defects might lead to the engagement of noncritical RHSLs. When measuring the gamma angle to identify critical RHSLs, posterior glenoid bone loss should be accounted for.
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Roux, Franck-Emmanuel, Jean-Albert Lotterie, Emmanuelle Cassol, Yves Lazorthes, Jean-Christophe Sol, and Isabelle Berry. "Cortical Areas Involved in Virtual Movement of Phantom Limbs: Comparison with Normal Subjects." Neurosurgery 53, no. 6 (2003): 1342–53. http://dx.doi.org/10.1227/01.neu.0000093424.71086.8f.
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Abstract OBJECTIVE To demonstrate that amputees performing “virtual” movements of their amputated limb activate cortical areas previously devoted to their missing limb, we studied amputees with functional magnetic resonance imaging (fMRI) and positron emission tomographic (PET) scans and compared the results with those of normal volunteers performing imaginary movements during fMRI acquisitions. METHODS Ten amputees (age range, 33–92 yr; average age, 49 yr; six men and four women; eight upper-limb and two lower-limb amputations) able to move their phantom limb at will were studied by fMRI (all patients) and PET scan (seven patients). The time between amputation and fMRI and PET studies ranged from 1 to 27 years (average, 13 yr). Patients were asked to perform virtual movements of the amputated limb and normal movements of the contralateral normal limb according to the functional images acquisition procedure. Movements of the stump were also used to differentiate stump cortical areas from virtual movement-activated areas. Ten right-handed volunteers, age- and sex-matched to the amputees, were also studied by fMRI. All volunteers were asked to perform four tasks during their fMRI study: imaginary movements of their right arm (1 task) and foot (1 task) and real movements of their left arm (1 task) and foot (1 task). RESULTS In amputees, virtual movements of the missing limbs produced contralateral primary sensorimotor cortex activation on both fMRI and PET scans. These activation areas, different from the stump activation areas, were similar in location to contralateral normal limb-activated areas. Quantitatively, in two amputees who claimed to be able to perform both slow and fast virtual movements, regional cerebral blood flow measured by PET scan in the precentral gyrus increased significantly during fast movements in comparison with slow virtual movements. In normal subjects, significant differences between real versus imaginary fMRI activations were found (for both foot and hand movements); imaginary right hand and foot tasks activated primarily the contralateral supplementary motor areas, with no significant activation detected in the contralateral precentral or postcentral gyri. CONCLUSION Primary sensorimotor cortical areas can be activated by phantom-limb movements and thus can be considered functional for several years or decades after amputation. In this study, we found that the location of the activation of these areas is comparable to that of activations produced by normal movements in control subjects or in amputees.
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Debnath, Mithu, Giacomo Valerio Iungo, W. Alan Brewer, et al. "Assessment of virtual towers performed with scanning wind lidars and Ka-band radars during the XPIA experiment." Atmospheric Measurement Techniques 10, no. 3 (2017): 1215–27. http://dx.doi.org/10.5194/amt-10-1215-2017.
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Abstract. During the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign, which was carried out at the Boulder Atmospheric Observatory (BAO) in spring 2015, multiple-Doppler scanning strategies were carried out with scanning wind lidars and Ka-band radars. Specifically, step–stare measurements were collected simultaneously with three scanning Doppler lidars, while two scanning Ka-band radars carried out simultaneous range height indicator (RHI) scans. The XPIA experiment provided the unique opportunity to compare directly virtual-tower measurements performed simultaneously with Ka-band radars and Doppler wind lidars. Furthermore, multiple-Doppler measurements were assessed against sonic anemometer data acquired from the meteorological tower (met-tower) present at the BAO site and a lidar wind profiler. This survey shows that – despite the different technologies, measurement volumes and sampling periods used for the lidar and radar measurements – a very good accuracy is achieved for both remote-sensing techniques for probing horizontal wind speed and wind direction with the virtual-tower scanning technique.
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Deakyne, Alex J., Tinen L. Iles, Alexander R. Mattson, and Paul A. Iaizzo. "Virtual Prototyping: Computational Device Placements within Detailed Human Heart Models." Applied Sciences 10, no. 1 (2019): 175. http://dx.doi.org/10.3390/app10010175.
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Data relative to anatomical measurements, spatial relationships, and device–tissue interaction are invaluable to medical device designers. However, obtaining these datasets from a wide range of anatomical specimens can be difficult and time consuming, forcing designers to make decisions on the requisite shapes and sizes of a device from a restricted number of specimens. The Visible Heart® Laboratories have a unique library of over 500 perfusion-fixed human cardiac specimens from organ donors whose hearts (and or lungs) were not deemed viable for transplantation. These hearts encompass a wide variety of pathologies, patient demographics, surgical repairs, and/or interventional procedures. Further, these specimens are an important resource for anatomical study, and their utility may be augmented via generation of 3D computational anatomical models, i.e., from obtained post-fixation magnetic resonance imaging (MRI) scans. In order to optimize device designs and procedural developments, computer generated models of medical devices and delivery tools can be computationally positioned within any of the generated anatomical models. The resulting co-registered 3D models can be 3D printed and analyzed to better understand relative interfaces between a specific device and cardiac tissues within a large number of diverse cardiac specimens that would be otherwise unattainable.
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Laukamp, Kai Roman, Amit Gupta, Nils Große Hokamp, et al. "Role of spectral-detector CT in reduction of artifacts from contrast media in axillary and subclavian veins: single institution study in 50 patients." Acta Radiologica 61, no. 4 (2019): 450–60. http://dx.doi.org/10.1177/0284185119868904.
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Background In CT imaging, a high concentration of iodinated contrast media in axillary and subclavian veins after brachial application can cause perivenous artifacts impairing diagnostic assessment of local vascular structures and soft tissue. Purpose To investigate reduction of perivenous hypo- and hyperattenuating artifacts of the axillary and subclavian veins using virtual monoenergetic images (VMI) in comparison to conventional CT images (CI), acquired on spectral-detector CT. Material and Methods 50 spectral-detector CT datasets of patients with perivenous artifacts from contrast media were included in this retrospective, institutional review board-approved study. CT images and virtual monoenergetic images (range 40–200 keV, 10-keV increments) were reconstructed from the same scans. Quantitative analysis was performed by region of interest-based assessment of mean attenuation (HU) and standard deviation in most pronounced hypo- and hyperdense artifacts and artifact-impaired arteries as well as muscle. Visually, artifact reduction, assessment of vessels, and surrounding soft tissue were rated on 5-point Likert-scales by two radiologists. Results In comparison to CT images, virtual monoenergetic images of ≥90 keV showed a significant reduction of hypo- and hyperattenuating artifacts (hypodense: CI -220.0±171.2 HU; VMI130keV -13.4±49.1 HU; hyperdense: CI 274.6±184.4 HU; VMI130keV 24.2±84.9 HU; P<0.001). Subjective analysis confirmed that virtual-monoenergetic images of ≥100 keV significantly reduced artifacts (hypodense: CI 2[1–3]; VMI130keV 5[4–5], hyperdense: CI 2[1–4]; VMI130keV 5[5–5], P<0.001) and improved diagnostic assessment. Best results for diagnostic assessment were noted for virtual monoenergetic images at 130 keV. Overcorrection of artifacts was observed at higher keV values. Interrater agreement was excellent for each evaluation and keV value (intraclass correlation coefficient 0.89). Conclusion Higher keV virtual monoenergetic images yielded significant reduction of contrast media artifacts and led to improved assessment of vessels and surrounding soft tissue. Recommended keV values for best diagnostic assessment are in the range of 100–160 keV.
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Kearns, D., and M. McJury. "Commissioning a new CT simulator I: CT simulator hardware." Journal of Radiotherapy in Practice 6, no. 03 (2007): 153–62. http://dx.doi.org/10.1017/s1460396907006097.
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AbstractThis paper reports on the commissioning tests performed on a new GE Lightspeed RT wide-bore computed tomography (CT) scanner with GE Advantage Sim software. This paper focuses on the laser marking system, CT hardware and the interfaces between each component of the system, and generalises the findings to most CT simulation systems currently available. A discussion on the commissioning of the virtual simulator software will follow in a separate paper. Three phantoms were used (two constructed in-house) to assist with a range of tests covering aspects such as the laser patient marking system, CT hardware, and connections between the CT scanner, virtual simulator system and the treatment planning system (TPS) and VARiS. Tests performed showed the CT simulation system to be working within acceptable tolerances suggested in the literature, and baseline data have been obtained against which future comparisons of system performance have been made. Where no tolerances were available, we have suggested suitable values. While considering tolerances on Hounsfield number variation that may lead to a dose error in excess of 2%, we found that in the case of low-kV CT scanning the range of Hounsfield numbers for dense bone was outside the acceptable limits for potential dose errors and so users were advised not to perform radiotherapy planning CT scans with kV below 100 kV.
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Fan, Yuzhou, Liangping Luo, Marija Djuric, et al. "Extracting Cross-Sectional Clinical Images Based on Their Principal Axes of Inertia." Scanning 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/1468596.
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Cross-sectional imaging is considered the gold standard in diagnosing a range of diseases. However, despite its widespread use in clinical practice and research, no widely accepted method is available to reliably match cross-sectional planes in several consecutive scans. This deficiency can impede comparison between cross-sectional images and ultimately lead to misdiagnosis. Here, we propose and demonstrate a method for finding the same imaging plane in images obtained during separate scanning sessions. Our method is based on the reconstruction of a “virtual organ” from which arbitrary cross-sectional images can be extracted, independent of the axis orientation in the original scan or cut; the key is to establish unique body coordinates of the organ from its principal axes of inertia. To verify our method a series of tests were performed, and the same cross-sectional plane was successfully extracted. This new approach offers clinicians access, after just a single scanning session, to the morphology and structure of a lesion through cross-sectional images reconstructed along arbitrary axes. It also aids comparable detection of morphological and structural changes in the same imaging plane from scans of the same patient taken at different times—thus potentially reducing the misdiagnosis rate when cross-sectional images are interpreted.
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Perkins, Elizabeth L., Saikat Basu, Guilherme J. M. Garcia, Robert A. Buckmire, Rupali N. Shah, and Julia S. Kimbell. "Ideal Particle Sizes for Inhaled Steroids Targeting Vocal Granulomas: Preliminary Study Using Computational Fluid Dynamics." Otolaryngology–Head and Neck Surgery 158, no. 3 (2017): 511–19. http://dx.doi.org/10.1177/0194599817742126.
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Objectives Vocal fold granulomas are benign lesions of the larynx commonly caused by gastroesophageal reflux, intubation, and phonotrauma. Current medical therapy includes inhaled corticosteroids to target inflammation that leads to granuloma formation. Particle sizes of commonly prescribed inhalers range over 1 to 4 µm. The study objective was to use computational fluid dynamics to investigate deposition patterns over a range of particle sizes of inhaled corticosteroids targeting the larynx and vocal fold granulomas. Study Design Retrospective, case-specific computational study. Setting Tertiary academic center. Subjects/Methods A 3-dimensional anatomically realistic computational model of a normal adult airway from mouth to trachea was constructed from 3 computed tomography scans. Virtual granulomas of varying sizes and positions along the vocal fold were incorporated into the base model. Assuming steady-state, inspiratory, turbulent airflow at 30 L/min, computational fluid dynamics was used to simulate respiratory transport and deposition of inhaled corticosteroid particles ranging over 1 to 20 µm. Results Laryngeal deposition in the base model peaked for particle sizes 8 to 10 µm (2.8%-3.5%). Ideal sizes ranged over 6 to 10, 7 to 13, and 7 to 14 µm for small, medium, and large granuloma sizes, respectively. Glottic deposition was maximal at 10.8% for 9-µm-sized particles for the large posterior granuloma, 3 times the normal model (3.5%). Conclusion As the virtual granuloma size increased and the location became more posterior, glottic deposition and ideal particle size generally increased. This preliminary study suggests that inhalers with larger particle sizes, such as fluticasone propionate dry-powder inhaler, may improve laryngeal drug deposition. Most commercially available inhalers have smaller particles than suggested here.
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Gassert, Felix G., Claudio E. Schacky, Christina Müller-Leisse, et al. "Calcium scoring using virtual non-contrast images from a dual-layer spectral detector CT: comparison to true non-contrast data and evaluation of proportionality factor in a large patient collective." European Radiology 31, no. 8 (2021): 6193–99. http://dx.doi.org/10.1007/s00330-020-07677-w.
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Abstract Objective Determination of coronary artery calcium scoring (CACS) in non-contrast computed tomography (CT) images has been shown to be an important prognostic factor in coronary artery disease (CAD). The objective of this study was to evaluate the accuracy of CACS from virtual non-contrast (VNC) imaging generated from spectral data in comparison to standard (true) non-contrast (TNC) imaging in a representative patient cohort with clinically approved software. Methods One hundred three patients referred to coronary CTA with suspicion of CAD were investigated on a dual-layer spectral detector CT (SDCT) scanner. CACS was calculated from both TNC and VNC images by software certified for medical use. Patients with a CACS of 0 were excluded from analysis. Results The mean age of the study population was 61 ± 11 years with 48 male patients (67%). Inter-quartile range of clinical CACS was 22–282. Correlation of measured CACS from true- and VNC images was high (0.95); p < 0.001. The slope was 3.83, indicating an underestimation of VNC CACS compared to TNC CACS by that factor. Visual analysis of the Bland-Altman plot of CACS showed good accordance with both methods after correction of VNC CACS by the abovementioned factor. Conclusions In clinical diagnostics of CAD, the determination of CACS is feasible using VNC images generated from spectral data obtained on a dual-layer spectral detector CT. When multiplied by a correction factor, results were in good agreement with the standard technique. This could enable radiation dose reductions by obviating the need for native scans typically used for CACS. Key Points • Calcium scoring is feasible from contrast-enhanced CT images using a dual-layer spectral detector CT scanner. • When multiplied by a correction factor, calcium scoring from virtual non-contrast images shows good agreement with the standard technique. • Omitting native scans for calcium scoring could enable radiation dose reduction.
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Tai, Alexander X., Kenneth D. Sack, Aalap Herur-Raman, and Walter C. Jean. "The Benefits of Limited Orbitotomy on the Supraorbital Approach: An Anatomic and Morphometric Study in Virtual Reality." Operative Neurosurgery 18, no. 5 (2019): 542–50. http://dx.doi.org/10.1093/ons/opz201.
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Abstract BACKGROUND Cadaveric studies on surgical anatomy and approaches are hampered by the limited number of specimens. Virtual reality (VR) technology can overcome this limitation, allowing for more in-depth statistical analysis of the data. OBJECTIVE To determine the benefit of a supraorbital ridge osteotomy in a supraorbital craniotomy targeting (1) the anterior communicating artery complex (ACOM), and (2) a lesion 25 mm above tuberculum sellae, using a large dataset generated by VR. METHODS Computed tomography scans of 30 subjects without cranial osseous pathology were identified for use with VR technology. After correlating VR and DICOM datasets, supraorbital craniotomies were simulated without and with removal of supraorbital ridge, bilaterally (n = 60). Area of freedom (AOF) from the outer table to the targets and the vertical center angle (VCA) to targets were calculated, before and after the orbitotomy. RESULTS For the ACOM, AOF averaged 496 mm2 (range: 322-805) and increased 8.9% to an average of 547 mm2 with the removal of the supraorbital ridge (P &lt; .001). VCA increased from 18.5 to 20.3 degrees. For the suprasellar target, AOF averaged 507 mm2 (range 324-772) and increased 42.5% to 722 mm2 after orbitotomy (P &lt; .001). VCA increased from 22.1 to 30.8 degrees. CONCLUSION VR technology is an emerging tool to study neurosurgical approaches. Here, we demonstrate with VR that the removal of the supraorbital ridge in a supraorbital craniotomy affords greater access to superiorly located lesions of the anterior fossa floor; however, deeper and lower lesions require a more aggressive orbital roof osteotomy to widen the exposure.
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Werner, B. S., J. Chaoui, and G. Walch. "Glenosphere design affects range of movement and risk of friction-type scapular impingement in reverse shoulder arthroplasty." Bone & Joint Journal 100-B, no. 9 (2018): 1182–86. http://dx.doi.org/10.1302/0301-620x.100b9.bjj-2018-0264.r1.
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Aims Scapular notching is a frequently observed radiographic phenomenon in reverse shoulder arthroplasty (RSA), signifying impingement of components. The purposes of this study were to evaluate the effect of glenoid component size and glenosphere type on impingement-free range of movement (ROM) for extension and internal and external rotation in a virtual RSA model, and to determine the optimal configuration to reduce the incidence of friction-type scapular notching. Materials and Methods Preoperative CT scans obtained in 21 patients (three male, 18 female) with primary osteoarthritis were analyzed using modelling software. Two concurrent factors were tested for impingement-free ROM and translation of the centre of rotation: glenosphere diameter (36 mm vs 39 mm) and type (centred, 2 mm inferior eccentric offset, 10° inferior tilt). Results Glenosphere size was most predictive of increased extension and external rotation, whereas lateralization of the centre of rotation was the most predictive factor for internal rotation. A larger diameter of glenosphere combined with a 10° tilted configuration demonstrated superior values for extension and external rotation, whereas the eccentric component improved internal rotation by a mean 8.9° (standard deviation 2.7°) compared with a standard concentric glenosphere. Conclusion Glenosphere configuration can be modified to increase range of movement in RSA. Friction-type scapular notching was most effectively reduced by use of a large-diameter glenosphere with 10° inferior tilt. Cite this article: Bone Joint J 2018;100-B:1182–6.
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Zegadło, Arkadiusz, Magdalena Żabicka, Aleksandra Różyk, and Ewa Więsik-Szewczyk. "A New Outlook on the Ability to Accumulate an Iodine Contrast Agent in Solid Lung Tumors Based on Virtual Monochromatic Images in Dual Energy Computed Tomography (DECT): Analysis in Two Phases of Contrast Enhancement." Journal of Clinical Medicine 10, no. 9 (2021): 1870. http://dx.doi.org/10.3390/jcm10091870.
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For some time, dual energy computed tomography (DECT) has been an established method used in a vast array of clinical applications, including lung nodule assessment. The aim of this study was to analyze (using monochromatic DECT images) how the X-ray absorption of solitary pulmonary nodules (SPNs) depends on the iodine contrast agent and when X-ray absorption is no longer dependent on the accumulated contrast agent. Sixty-six patients with diagnosed solid lung tumors underwent DECT scans in the late arterial phase (AP) and venous phase (VP) between January 2017 and June 2018. Statistically significant correlations (p ≤ 0.001) of the iodine contrast concentration were found in the energy range of 40–90 keV in the AP phase and in the range of 40–80 keV in the VP phase. The strongest correlation was found between the concentrations of the contrast agent and the scanning energy of 40 keV. At the higher scanning energy, no significant correlations were found. We concluded that it is most useful to evaluate lung lesions in DECT virtual monochromatic images (VMIs) in the energy range of 40–80 keV. We recommend assessing SPNs in only one phase of contrast enhancement to reduce the absorbed radiation dose.
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Kim, Jaeyoung, and Jonathan Day. "Establishing a New Bony Landmark for Safe Screw Insertion in Medial Displacement Calcaneal Osteotomy: A Simulation-Based Approach." Foot & Ankle Orthopaedics 5, no. 4 (2020): 2473011420S0029. http://dx.doi.org/10.1177/2473011420s00290.
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Category: Hindfoot; Other Introduction/Purpose: Medial displacement calcaneal osteotomy (MDCO) is a commonly performed procedure in flatfoot reconstruction. Fixation is often achieved with screws due to its ability to compress across the osteotomy site. Screws are placed via a free-handed technique without direct fluoroscopic visualization, due to difficulty attaining a simultaneous axial calcaneal view. In addition, the posterior calcaneal tuber translates medially after displacement, resulting in altered anatomical geometry. It is therefore important to establish a reliable external bony landmark when performing free-handed interfragmentary fixation in order to avoid potential screw-related complications and to provide better surgical technique and fixation. The purposes of this study are to validate a new external bony landmark and to establish the appropriate trajectory and screw length for free-hand screw fixation in MDCO. Methods: A total of 84 postoperative computed tomography (CT) scans of MDCO in 70 patients were analyzed. The images were reconstructed using a 3-dimensional simulation program (Vworks 4.0, Cybermed). Virtual screw insertion was simulated by aiming towards two bony landmarks: the base of the 5th metatarsal in the axial plane, and the sinus tarsi in the sagittal plane (Figure 1). A grading system was also utilized to classify scenarios in which the screw breached the distal cortical wall: Grade 1 was defined as contact between the virtual screw and the cortex, Grade 2 as the screw approaching the outer margin of the cortex, and Grade 3 as the screw penetrating the outer cortex. The trajectory angle between the screw and the osteotomy, as well as the screw size, were also measured. Results: The average age of patients was 24.5 (range, 19 to 53), and 100% were males. The average displacement of the posterior calcaneal fragment was 7.3+-1.5 mm (range, 3.9 to 13.8). Among the 84 virtual screws, only five (6.0%) breached the medial cortical wall of the osteotomized calcaneus. All medial breaches were Grade 1. None of the virtual screws breached the lateral cortical wall. Mean trajectory angle between the virtual screw and the osteotomy site was 74.9+-6.7˚ (range, 60.0 to 89.8˚). In the perioperative data, estimated maximum screw length by simulation was 55.6+-4.4 mm (range, 50 to 65). Conclusion: Our results suggest that the optimal trajectory of free-handed screw placement can be determined through simulation of calcaneal interfragmentary screw insertion using postoperative CT imaging. Using this simulation technology, we determined a trajectory towards the sinus tarsi on the sagittal plane and the base of the 5th metatarsal on the axial plane to be a reliable external bony landmark for placement of screws in MDCO. These promising results have potential implications in achieving better fixation as well as improving union rates and operative outcomes.
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Poux, Florent, Romain Neuville, Gilles-Antoine Nys, and Roland Billen. "3D Point Cloud Semantic Modelling: Integrated Framework for Indoor Spaces and Furniture." Remote Sensing 10, no. 9 (2018): 1412. http://dx.doi.org/10.3390/rs10091412.
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3D models derived from point clouds are useful in various shapes to optimize the trade-off between precision and geometric complexity. They are defined at different granularity levels according to each indoor situation. In this article, we present an integrated 3D semantic reconstruction framework that leverages segmented point cloud data and domain ontologies. Our approach follows a part-to-whole conception which models a point cloud in parametric elements usable per instance and aggregated to obtain a global 3D model. We first extract analytic features, object relationships and contextual information to permit better object characterization. Then, we propose a multi-representation modelling mechanism augmented by automatic recognition and fitting from the 3D library ModelNet10 to provide the best candidates for several 3D scans of furniture. Finally, we combine every element to obtain a consistent indoor hybrid 3D model. The method allows a wide range of applications from interior navigation to virtual stores.
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Calhoun, R., R. Heap, M. Princevac, R. Newsom, H. Fernando, and D. Ligon. "Virtual Towers Using Coherent Doppler Lidar during the Joint Urban 2003 Dispersion Experiment." Journal of Applied Meteorology and Climatology 45, no. 8 (2006): 1116–26. http://dx.doi.org/10.1175/jam2391.1.
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Abstract During the Joint Urban 2003 (JU2003) atmospheric field experiment in Oklahoma City, Oklahoma, of July 2003, lidar teams from Arizona State University and the Army Research Laboratory collaborated to perform intersecting range–height indicator scans. Because a single lidar measures radial winds, that is, the dot product of the wind vector with a unit vector pointing along the lidar beam, the data from two lidars viewing from different directions can be combined to produce horizontal velocity vectors. Analysis programs were written to retrieve horizontal velocity vectors for a series of eight vertical profiles to the southwest (approximately upwind) of the downtown urban core. This technique has the following unique characteristics that make it well suited for urban meteorology studies: 1) continuous vertical profiles from far above the building heights to down into the street canyons can be measured and 2) the profiles can extend to very near the ground without a loss of accuracy (assuming clear lines of site). The period of time analyzed spans from 1400 to 1730 UTC (0900–1230 local time) on 9 July 2003. Both shear and convective heating are important during the development of the boundary layer over this period of time. Differences in 10- and 20-min mean profiles show the effect of the variation of position approaching the urban core; for example, several hundred meters above the ground, velocity magnitudes for profiles separated by less than a kilometer may differ by over 1 m s−1. The effect of the increased roughness associated with the central business district can be seen as a deceleration of the velocity and a turning of the wind direction as the flow approaches the core, up to approximately 10° for some profiles. This effect is evident below 400–500 m both in the wind directions and magnitudes. Recommendations are given for how this type of data can be used in a comparison with model data.
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Eberhard, Matthias, Victor Mergen, Kai Higashigaito, et al. "Coronary Calcium Scoring with First Generation Dual-Source Photon-Counting CT—First Evidence from Phantom and In-Vivo Scans." Diagnostics 11, no. 9 (2021): 1708. http://dx.doi.org/10.3390/diagnostics11091708.
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We evaluated the accuracy of coronary artery calcium (CAC) scoring on a dual-source photon-counting detector CT (PCD-CT). An anthropomorphic chest phantom underwent ECG-gated sequential scanning on a PCD-CT at 120 kV with four radiation dose levels (CTDIvol, 2.0–8.6 mGy). Polychromatic images at 120 kV (T3D) and virtual monoenergetic images (VMI), from 60 to 75 keV without quantum iterative reconstruction (no QIR) and QIR strength levels 1–4, were reconstructed. For reference, the same phantom was scanned on a conventional energy-integrating detector CT (120 kV; filtered back projection) at identical radiation doses. CAC scoring in 20 patients with PCD-CT (120 kV; no QIR and QIR 1–4) were included. In the phantom, there were no differences between CAC scores of different radiation doses (all, p > 0.05). Images with 70 keV, no QIR (CAC score, 649); 65 keV, QIR 3 (656); 65 keV; QIR4 (648) and T3D, QIR4 (656) showed a <1% deviation to the reference (653). CAC scores significantly decreased at increasing QIR levels (all, p < 0.001) and for each 5 keV-increase (all, p < 0.001). Patient data (median CAC score: 86 [inter-quartile range: 38–978] at 70 keV) confirmed relationships and differences between reconstructions from the phantom. First phantom and in-vivo experience with a clinical dual-source PCD-CT system shows accurate CAC scoring with VMI reconstructions at different radiation dose levels.
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Hague, Christina, Marianne Aznar, Lei Dong, et al. "Inter-fraction robustness of intensity-modulated proton therapy in the post-operative treatment of oropharyngeal and oral cavity squamous cell carcinomas." British Journal of Radiology 93, no. 1107 (2020): 20190638. http://dx.doi.org/10.1259/bjr.20190638.
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Objective: To evaluate dosimetric consequences of inter-fraction setup variation and anatomical changes in patients receiving multifield optimised (MFO) intensity modulated proton therapy for post-operative oropharyngeal (OPC) and oral cavity (OCC) cancers. Methods: Six patients receiving MFO for post-operative OPC and OCC were evaluated. Plans were robustly optimised to clinical target volumes (CTVs) using 3 mm setup and 3.5% range uncertainty. Weekly online cone beam CT (CBCT) were performed. Planning CT was deformed to the CBCT to create virtual CTs (vCTs) on which the planned dose was recalculated. vCT plan robustness was evaluated using a setup uncertainty of 1.5 mm and range uncertainty of 3.5%. Target coverage, D95%, and hotspots, D0.03cc, were evaluated for each uncertainty along with the vCT-calculated nominal plan. Mean dose to organs at risk (OARs) for the vCT-calculated nominal plan and relative % change in weight from baseline were evaluated. Results: Robustly optimised plans in post-operative OPC and OCC patients are robust against inter-fraction setup variations and range uncertainty. D0.03cc in the vCT-calculated nominal plans were clinically acceptable across all plans. Across all patients D95% in the vCT-calculated nominal treatment plan was at least 100% of the prescribed dose. No patients lost ≥10% weight from baseline. Mean dose to the OARs and max dose to the spinal cord remained within tolerance. Conclusion: MFO plans in post-operative OPC and OCC patients are robust to inter-fraction uncertainties in setup and range when evaluated over multiple CT scans without compromising OAR mean dose. Advances in knowledge: This is the first paper to evaluate inter-fraction MFO plan robustness in post-operative head and neck treatment.
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Busse, J., S. Galindo Torres, Alexander Scheuermann, L. Li, and D. Bringemeier. "Micro-Scale Flow Simulations and Permeability Estimation of Cleat Networks in Coal." Applied Mechanics and Materials 846 (July 2016): 42–47. http://dx.doi.org/10.4028/www.scientific.net/amm.846.42.
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Coal mining raises a number of environmental and operational challenges, including the impact of changing groundwater levels and flow patterns on adjacent aquifer and surface water systems. Therefore it is of paramount importance to fully understand the flow of water and gases in the geological system on all scales. Flow in coal seams takes place on a wide range of scales from large faults and fractures to the micro-structure of a porous matrix intersected by a characteristic cleat network. On the micro-scale these cleats provide the principal source of permeability for fluid and gas flow. Description of the behaviour of the flow within the network is challenging due to the variations in number, sizing, orientation, aperture and connectivity at a given site. This paper presents a methodology to simulate flow and investigate the permeability of fractured media. A profound characterization of the geometry of the cleat network in micrometer resolution can be derived by CT-scans. The structural information is fed into a Lattice Boltzmann Method (LBM) based model that allows the implementation of virtual flow experiments. With the application of suitable hydraulic boundary conditions the full permeability tensor can be calculated in 3D.
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Said, Hatem Galal, Tarek Nabil Fetih, Hosam Elsayed Abd-Elzaher, and Simon Martin Lambert. "Radiographic parameters and a novel fluoroscopic control view for posterior screw fixation of coracoid base fractures." SICOT-J 6 (2020): 9. http://dx.doi.org/10.1051/sicotj/2020008.
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Introduction: Coracoid fractures have the potential to lead to inadequate shoulder function. Most coracoid base fractures occur with scapular fractures and the posterior approaches would be utilized for surgical treatment. We investigated the possibility of fixing the coracoid through the same approach without an additional anterior approach. Materials and methods: Multi-slice CT scans of 30 shoulders were examined and the following measurements were performed by an independent specialized radiologist: posterior coracoid screw entry point measured form infraglenoid tubercle, screw trajectory in coronal plane in relation to scapular spine and lateral scapular border, screw trajectory in sagittal plane in relation to glenoid face bisector line and screw length. We used the results from the CT study to guide postero-anterior coracoid screw insertion under fluoroscopic guidance on two fresh frozen cadaveric specimens to assess the reproducibility of accurate screw placement based on these parameters. We also developed a novel fluoroscopic projection, the anteroposterior (AP) coracoid view, to guide screw placement in the para-coronal plane. Results: The mean distance between entry point and the infraglenoid tubercle was 10.8 mm (range: 9.2–13.9, SD 1.36). The mean screw length was 52 mm (range: 46.7–58.5, SD 3.3). The mean sagittal inclination angle between was 44.7 degrees (range: 25–59, SD 5.8). The mean angle between screw line and lateral scapular border was 47.9 degrees (range: 34–58, SD 4.3). The mean angle between screw line and scapular spine was 86.2 degrees (range: 75–95, SD 4.9). It was easy to reproduce the screw trajectory in the para-coronal plane; however, multiple attempts were needed to reach the correct angle in the parasagittal plane, requiring several C-arm corrections. Conclusion: This study facilitates posterior fixation of coracoid process fractures and will inform the “virtual visualization” of coracoid process orientation.
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Guarnieri, A., F. Fissore, A. Masiero, and A. Vettore. "FROM TLS SURVEY TO 3D SOLID MODELING FOR DOCUMENTATION OF BUILT HERITAGE: THE CASE STUDY OF PORTA SAVONAROLA IN PADUA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W5 (August 18, 2017): 303–8. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w5-303-2017.
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It is a matter of fact that 3D visualisation and proper documentation of cultural objects helps to preserve the history and memories of historic buildings, archaeological sites and cultural landscapes, and supports economic growth by stimulating cultural tourism. Preservation, visualisation and recreation of valuable historical and architectural objects and places has always been a serious challenge for specialists in the field. Today, the rapid developments in the fields of close-range photogrammetry, terrestrial laser scanning (TLS) and computer vision (CV) enable to carry out highly accurate 3D models so as to be extremely effective and intuitive for users who have stringent requirements and high expectations. In this note we present the results of the survey and 3D modeling of an ancient gate, Porta Savonarola, located within the remains of the medieval town walls surrounding the historical city center of Padua, Italy. The work has been undertaken within the framework of the project “Walls Multimedia Museum” (WMM) promoted by the local private association “Padua Walls Committee”. The goal of the project was to develop a prototype of an “extended” virtual museum, spreaded along most interesting locations of the town walls. The survey of the ancient gate was performed with a Leica C10 and P20 terrestrial laser scanners. Once the acquired scans were properly merged together, a solid model was generated from the global point cloud, and plans and elevations were extracted from it for restoration purposes. A short multimedia video was also created for the “Walls Multimedia Museum”, showing both the outer and inner part of the gate. In the paper we will discuss all the steps and challenges addressed to provide the 3D solid model of Porta Savonarola from the TLS data.
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Kim, Terrence T., Doniel Drazin, Faris Shweikeh, Robert Pashman, and J. Patrick Johnson. "Clinical and radiographic outcomes of minimally invasive percutaneous pedicle screw placement with intraoperative CT (O-arm) image guidance navigation." Neurosurgical Focus 36, no. 3 (2014): E1. http://dx.doi.org/10.3171/2014.1.focus13531.
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Object Intraoperative CT image–guided navigation (IGN) has been increasingly incorporated into minimally invasive spine surgery (MIS). The vast improvement in image resolution and virtual real-time images with CT-IGN has proven superiority over traditional fluoroscopic techniques. The authors describe their perioperative MIS technique using the O-arm with navigation, and they report their postoperative experience, accuracy results, and technical aspects. Methods A retrospective review of 48 consecutive adult patients undergoing minimally invasive percutaneous posterior spinal fusion with intraoperative CT-IGN between July 2010 and August 2013 at Cedars-Sinai Medical Center was performed. Two surgeons assessed 290 screws in a blinded fashion on intraoperative O-arm images and postoperative CT scans for bony pedicle wall breach. Grade 1 breach was defined to be < 2 mm, Grade 2 breach to be between 2 and 4 mm, and a Grade 3 breach to be > 4 mm. Additionally, anterior vertebral body breach was recorded. Results Of 290 pedicle screws placed, 280 (96.6%) were in an acceptable position without cortical wall or anterior breach. Of the 10 breaches (3.4%) 5 were lateral (50%), 4 were medial, and 1 was anterior; 90% of breaches were Grade 1–2 and all medial breaches were Grade 1. The one Grade 3 breach was lateral. No vascular or neurological complications were observed intraoperatively, and no significant postoperative complications were noted. The mean clinical follow-up period was 18 months (range 3–39 months). The overall clinical outcomes, measured using the visual analog scale (back pain scores), were improved significantly postoperatively at 3 months compared with preoperatively (visual analog score 6.35 vs 3.57; p < 0.0001). No revision surgery was performed for screw misplacement or neurological deterioration. Conclusions New CT-IGN with the mobile O-arm scanner has increased the accuracy of pedicle screw/instrumentation placement using MIS techniques. The authors' high (96.6%) accuracy rate in MIS compares favorably with historical published accuracy rates for fluoroscopy-based techniques. Additional advantages of CT-IGN over fluoroscopic imaging methods are lower occupational radiation exposure for the surgical team, reduced need for postoperative imaging, and decreased rates of revision surgery. For now, the authors simply conclude that use of intraoperative CT-IGN is safe and accurate.
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Lerch, Till D., Adam Boschung, Inga A. S. Todorski, et al. "Femoroacetabular Impingement Patients With Decreased Femoral Version Have Different Impingement Locations and Intra- and Extraarticular Anterior Subspine FAI on 3D-CT–Based Impingement Simulation: Implications for Hip Arthroscopy." American Journal of Sports Medicine 47, no. 13 (2019): 3120–32. http://dx.doi.org/10.1177/0363546519873666.
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Background: It remains unclear whether decreased femoral version (FV) causes anterior intra- or extra-articular femoroacetabular impingement (FAI). Therefore, we evaluated symptomatic hips with decreased FV, with and without cam and pincer FAI, by using computed tomography (CT)–based virtual 3-dimensional (3D) impingement simulation and compared this group with patients with normal FV and with asymptomatic hips. Purpose: To investigate (1) the osseous range of motion, (2) the osseous femoral and acetabular impingement zones, and (3) whether hip impingement is extra- or intra-articular in symptomatic hips with FAI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: An institutional review board–approved, retrospective comparative analysis was performed on a total of 84 hips in 68 participants. Of these, 37 hips in 24 symptomatic patients with FAI had decreased FV. These hips were compared with 21 hips of 18 symptomatic patients with anterior FAI with normal FV (10°-25°) and 26 asymptomatic hips with no FAI and normal FV. All patients with FAI were symptomatic and had anterior hip pain and a positive anterior impingement test. They underwent pelvic CT scans to measure FV. Decreased FV was defined as FV less than 5°. The 37 hips with decreased FV presented both with and without cam and pincer FAI. All 84 hips were evaluated by use of CT-based 3D models and a validated 3D range of motion and impingement simulation. Asymptomatic hips were contralateral normal hips imaged in patients undergoing total hip arthroplasty. Results: Hips with FAI combined with decreased FV had a significantly ( P < .001) lower mean flexion (114°± 8° vs 125°± 13°) and internal rotation (IR) at 90° of flexion (18°± 6° vs 32°± 9°, P < .001) compared with the asymptomatic control group. Symptomatic patients with FAI and normal FV had flexion of 120°± 16° and IR at 90° of flexion of 23°± 15°. In a subgroup analysis, we found a significantly ( P < .001) lower IR in 90° of flexion in hips with FV less than 5° combined with mixed-type FAI compared with hips with FV less than 5° without a cam- or pincer-type deformity. The maximal acetabular impingement zone for hips with decreased FV was located at the 2-o’clock position and ranged from 1 to 3 o’clock. In hips with decreased FV, most of the impingement locations were intra-articular but 32% of hips had combined intra- and extra-articular FAI in internal rotation in 90° of flexion. During the flexion-adduction-IR test performed in 10° and 20° of adduction, extra-articular subspine FAI had significantly ( P < .001) higher prevalence (68% and 84%) in hips with decreased FV compared with normal hips. Conclusion: Hips with FAI and decreased FV had less flexion and internal rotation in 90° of flexion compared with the asymptomatic control group. The majority of hip impingement due to low FV was intra-articular, but one-third of samples had combined intra- and extra-articular subspine FAI. Anterior extra- and intra-articular hip impingement can be present in patients who have FAI with decreased FV. This could be important for patients undergoing hip arthroscopy.
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Amen, Daniel G., Joseph Wu, Noble George, and Andrew Newberg. "Patterns of Regional Cerebral Blood Flow as a Function of Obesity in Adults." Journal of Alzheimer's Disease 77, no. 3 (2020): 1331–37. http://dx.doi.org/10.3233/jad-200655.
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Background: While obesity has been shown to be a risk factor for Alzheimer’s disease, the potential mechanisms underlying this risk may be clarified with better understanding of underlying physiology in obese persons. Objective: To identify patterns of cerebral perfusion abnormality in adults as a function of body mass index (BMI) defined weight categories, including overweight or obese status. Methods: A large psychiatric cohort of 35,442 brain scans across 17,721 adults (mean age 40.8±16.2 years, range 18–94 years) were imaged with SPECT during baseline and concentration scans, the latter done after each participant completed the Connors Continuous Performance Test II. ANOVA was done to identify patterns of perfusion abnormality in this cohort across BMI designations of underweight (BMI < 18.5), normal weight (BMI = 18.5 to 24.9), overweight (BMI 24.9 to 29.9), obesity (BMI≥30), and morbid obesity (BMI≥40). This analysis was done for 128 brain regions quantifying SPECT perfusion using the automated anatomical labeling (AAL) atlas. Results: Across adulthood, higher BMI correlated with decreased perfusion on both resting and concentration brain SPECT scans. These are seen in virtually all brain regions, including those influenced by AD pathology such as the hippocampus. Conclusion: Greater BMI is associated with cerebral perfusion decreases in both resting and concentration SPECT scans across adulthood.
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Olivero, William C., J. Richard Lister, and Patrick W. Elwood. "The natural history and growth rate of asymptomatic meningiomas: a review of 60 patients." Journal of Neurosurgery 83, no. 2 (1995): 222–24. http://dx.doi.org/10.3171/jns.1995.83.2.0222.
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✓ Little is known about the natural history and growth rate of asymptomatic meningiomas. To better delineate this problem, the authors reviewed the clinical records and imaging studies of the last 60 patients diagnosed with asymptomatic meningiomas at their institution. There were 45 women and 15 men, whose ages ranged from 38 to 84 years, with a mean age of 66 years. The most common tumor location was convexity (25 patients), but virtually all locations were represented. Three patients were lost to follow up. The average clinical follow-up review of the remaining 57 patients was 32 months (range 6 months to 15 years). None of the patients became symptomatic from an enlarging tumor during their follow-up period. Typically, once a meningioma was diagnosed, follow-up scans were obtained at 3 months, 9 months, and then yearly or every other year thereafter. Forty-five patients underwent follow-up scans, with comparison of tumor size to that found on the initial scan, over a period ranging from 3 months to 15 years. Thirty-five patients have shown no growth in their tumor size, with an average imaging follow up of 29 months (range 3–72 months). Ten patients have shown tumor growth calculated as an increase in the maximum diameter of the tumor. This growth ranged from 0.2 cm over 180 months to 1 cm over 12 months, with an average of 0.24 cm per year. Average imaging follow up for these patients was 47 months (range 6 months to 15 years). The authors conclude that patients with asymptomatic meningiomas need close clinical and radiological follow up to rule out other disease processes and to rule out rapidly enlarging tumors. Although the average follow-up time was short, the vast majority of these tumors appeared to show minimal or no growth over periods of time measured in years. With modern noninvasive imaging techniques, these tumors can be safely observed until they enlarge significantly or become symptomatic.
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Bülow, Heiko, and Andreas Birk. "Synthetic Aperture Sonar (SAS) without Navigation: Scan Registration as Basis for Near Field Synthetic Imaging in 2D." Sensors 20, no. 16 (2020): 4440. http://dx.doi.org/10.3390/s20164440.
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Sonars are essential for underwater sensing as they can operate over extended ranges and in poor visibility conditions. The use of a synthetic aperture is a popular approach to increase the resolution of sonars, i.e., the sonar with its N transducers is positioned at k places to generate a virtual sensor with kN transducers. The state of the art for synthetic aperture sonar (SAS) is strongly coupled to constraints, especially with respect to the trajectory of the placements and the need for good navigation data. In this article, we introduce an approach to SAS using registration of scans from single arrays, i.e., at individual poses of arbitrary trajectories, hence avoiding the need for navigation data of conventional SAS systems. The approach is introduced here for the near field using the coherent phase information of sonar scans. A Delay and Sum (D&S) beamformer (BF) is used, which directly operates on pixel/voxel form on a Cartesian grid supporting the registration. It is shown that this pixel/voxel-based registration and the coherent processing of several scans forming a synthetic aperture yields substantial improvements of the image resolution. The experimental evaluation is done with an advanced simulation tool generating realistic 2D sonar array data, i.e., with simulations of a linear 1D antenna reconstructing 2D images. For the image registration of the raw sonar scans, a robust implementation of a spectral method is presented. Furthermore, analyses with respect to the trajectories of the sensor locations are provided to remedy possible grating lobes due to the gaping positions of the transmitter devices.
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Kebbach, Maeruan, Christian Schulze, Christian Meyenburg, et al. "An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements." Applied Sciences 11, no. 6 (2021): 2852. http://dx.doi.org/10.3390/app11062852.
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The calculation of range of motion (ROM) is a key factor during preoperative planning of total hip replacements (THR), to reduce the risk of impingement and dislocation of the artificial hip joint. To support the preoperative assessment of THR, a magnetic resonance imaging (MRI)-based computational framework was generated; this enabled the estimation of patient-specific ROM and type of impingement (bone-to-bone, implant-to-bone, and implant-to-implant) postoperatively, using a three-dimensional computer-aided design (CAD) to visualize typical clinical joint movements. Hence, patient-specific CAD models from 19 patients were generated from MRI scans and a conventional total hip system (Bicontact® hip stem and Plasmacup® SC acetabular cup with a ceramic-on-ceramic bearing) was implanted virtually. As a verification of the framework, the ROM was compared between preoperatively planned and the postoperatively reconstructed situations; this was derived based on postoperative radiographs (n = 6 patients) during different clinically relevant movements. The data analysis revealed there was no significant difference between preoperatively planned and postoperatively reconstructed ROM (∆ROM) of maximum flexion (∆ROM = 0°, p = 0.854) and internal rotation (∆ROM = 1.8°, p = 0.917). Contrarily, minor differences were observed for the ROM during maximum external rotation (∆ROM = 9°, p = 0.046). Impingement, of all three types, was in good agreement with the preoperatively planned and postoperatively reconstructed scenarios during all movements. The calculated ROM reached physiological levels during flexion and internal rotation movement; however, it exceeded physiological levels during external rotation. Patients, where implant-to-implant impingement was detected, reached higher ROMs than patients with bone-to-bone impingement. The proposed framework provides the capability to predict postoperative ROM of THRs.
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Kortekaas, Rudie, R. Paul Maguire, Thomas I. Cremers, Durk Dijkstra, Aren van Waarde, and Klaus L. Leenders. "In vivo Binding Behavior of Dopamine Receptor Agonist (+)−PD 128907 and Implications for the “Ceiling Effect” in Endogenous Competition Studies with [11C]Raclopride—a Positron Emission Tomography Study in Macaca mulatta." Journal of Cerebral Blood Flow & Metabolism 24, no. 5 (2004): 531–35. http://dx.doi.org/10.1097/00004647-200405000-00007.
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In in vivo positron emission tomography (PET) studies, dopamine that is released secondary to amphetamine administration appears unable to achieve a receptor occupancy that is significantly higher than 50% (“ceiling effect”). Also with exogenous agonists no studies have reported a higher than 50% occupancy. To investigate the feasibility of exceeding 50% occupancy in vivo with a dopamine receptor agonist we administered D2/D3 agonist (+)−PD 128907 over an extensive dose range. Two anesthetised Macaca mulatta males were used in a bolus-infusion protocol for [11C]raclopride. (+)- PD 128907 was administered as an intravenous challenge during separate PET scans in a dose range of 10 to 10000 nmol/kg. Occupancy by (+)−PD 128907 was estimated by comparing the binding before and after challenge. In a striatal region of interest, receptor occupancy by (+)−PD 128907 increased in an orderly dose-dependent manner to a maximum of at least 85%. This is the first indication that virtually all dopamine D2/D3 receptors in the striatum are in principle accessible to agonist binding. In the case of dopamine a number of protective mechanisms may be responsible for the ceiling effect.
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O'Broin, Eoin S., Martina Morrin, Eamonn Breathnach, David Allcutt, and Michael J. Earley. "Titanium Mesh and Bone Dust Calvarial Patch during Cranioplasty." Cleft Palate-Craniofacial Journal 34, no. 4 (1997): 354–56. http://dx.doi.org/10.1597/1545-1569_1997_034_0353_tmabdc_2.3.co_2.
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A technique of filling calvarial detects using bone dust reinforced with titanium Micro Mesh (Leibinger®) was investigated using plain x-ray films and computed tomography (CT) in seven consecutive patients (age range, 7–21 years). The aim of our study was to assess whether, in the presence of the titanium, bone dust harvested with a power burr promotes persistent ossification that is comparable with adjacent bone. The mesh was localized by standard skull plain x-ray films, and orthogonal CT scans were obtained at between 9 and 18 months post-operatively. An ultrahigh-resolution algorithm was used to detect neoossification on either side of the Micro Mesh (1-mm collimation, 330-mA and 120 KV(p) at the center of 400 HU, and window width of 2000 Hu). The mesh induced minimal streak artifact. Virtually no new bone formation was seen. It appears that bone dust was completely reabsorbed in this patient group even in the presence of semi-rigid fixation.
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Welt, S., C. R. Divgi, F. X. Real, et al. "Quantitative analysis of antibody localization in human metastatic colon cancer: a phase I study of monoclonal antibody A33." Journal of Clinical Oncology 8, no. 11 (1990): 1894–906. http://dx.doi.org/10.1200/jco.1990.8.11.1894.
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A33 is a mouse immunoglobulin G2a (IgG2a) monoclonal antibody (mAb) that detects a heat-stable, protease- and neuraminidase-resistant epitope. The antigen is homogeneously expressed by virtually all colon cancers and in the colon mucosa but not other epithelial tissues. The biodistribution and imaging characteristics of iodine-131 (131I)-mAbA33 were studied in colorectal carcinoma patients with hepatic metastases. Antibody labeled with 2 to 5 mCi of 131I was administered intravenously (IV) 7 to 8 days before surgery at five dose levels, ranging from 0.2 mg to 50 mg, with three or more patients entered at each dose level. In addition, three patients received 2 mg 131I-mAbTA99 (an isotype-matched control mAb) together with 125I-mAbA33. Evaluation included whole-body imaging with a gamma camera, technetium-99 (99mTc)-human serum albumin blood pool scans, liver/spleen scans, abdominal computed tomographic (CT) scans, hepatic arteriograms, antibody pharmacokinetics, and assessment of antibody distribution in biopsied malignant and normal tissues. Selective mAbA33 localization to tumor tissue was demonstrated in 19 of 20 patients, and external imaging correlated with surgical inspection, pathologic examination, and tissue radioactivity. One week after antibody administration, tumor:liver ratios ranged from 6.9:1 to 100:1 and tumor:serum ratios from 4.1:1 to 25.2:1. 99mTc-albumin blood pool studies showed that liver metastases were hypovascular, emphasizing the selective localization of mAbA33 despite poor tumor-blood flow. Control mAbTA99 studies showed mAbA33 localization was antigen-specific; tumor:liver ratios were 2.3- to 45-fold higher for specific antibody. In metastatic lesions, radioisotope was localized primarily in the viable periphery; however, even the necrotic tumor core concentrated specific antibody. External imaging showed isotope visualization in some patients' large bowel; whether this represents specific antibody uptake or gastric iodine secretion is unclear.
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Outlaw, R. A., S. N. Sankaran, G. B. Hoflund, and M. R. Davidson. "Oxygen transport through high-purity, large-grain Ag." Journal of Materials Research 3, no. 6 (1988): 1378–84. http://dx.doi.org/10.1557/jmr.1988.1378.
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The permeation of oxygen through high-purity, large-grain Ag membranes has been studied over the temperature range of 400–800 °C. The permeability was found to be linear and repeatable, but the magnitude was 3.2 times smaller than that determined by past research. This factor may be due to negligible grain boundary diffusion that exists in this work. Auger electron spectroscopy (AES) does, however, suggest the importance of grain boundaries since intragranular oxygen was virtually undetectable and since AES line scans show substantial oxygen signals around the grain boundaries. The diffusivity measurements were found to exhibit two distinct linear regions, one above and one below a critical temperature of 630 °C. The high-temperature data have an activation energy (11.1 kcal mol−1) similar to that reported by others, but the low-temperature data have a comparatively larger activation energy (15.3 kcal mol−1). Vacuum desorption of the oxygen-saturated Ag was found to occur at the critical temperature of 630 °C, which is consistent with the increased mobility of oxygen atoms in the higher temperature regime. The higher activation energy observed in the lower temperature regime is probably due to the higher efficiency of traps.
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Bosco, A., A. D’Andrea, M. Nuzzolo, and P. Zanfagna. "A BIM APPROACH FOR THE ANALYSIS OF AN ARCHAEOLOGICAL MONUMENT." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W9 (January 31, 2019): 165–72. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w9-165-2019.
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<p><strong>Abstract.</strong> In 2010 an Italian team started new on-field investigations in the area of the Sun Temple of Niuserra, 6<span class="thinspace"></span>km south of the pyramids of Giza. The archaeological research was planned to re-examine the monument after its discovery in 1898. The work was mainly aimed at a general evaluation of the archaeological structures, still visible, in order to establish an updated plan of the temple. More than 100 scans and several 3D models by close-range photogrammetry have been acquired, processed and integrated to virtually reconstruct the archaeological area.</p><p>To manage all available 3D datasets, allowing to propose new hypothesis about the monument, a BIM has been developed. Thanks to this approach different categories of environmental and technological objects have been created and analysed. The paper deals with the recent achievements, especially regarding the hierarchical conceptualisation of the architectural components. In particular, the contribution dwells on the analysis of the monument starting from the identification of a parametric library built on the semantic decomposition of the 3D replica.</p>
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Butcher, Kirsten, Madlyn Runburg, and Michelle Hudson. "Using digitized objects to promote critical thinking and engagement in classrooms." Library Hi Tech News 34, no. 7 (2017): 12–15. http://dx.doi.org/10.1108/lhtn-06-2017-0039.
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Purpose This paper aims to examine the impact of using digitized objects for inquiry with middle-school classrooms. Research analyzed critical thinking processes and student engagement during collaborative investigations with 3D models of authentic objects. Design/methodology/approach Digitized objects were 3D scans of fossils from the paleontology collection at the Natural History Museum of Utah implemented as 3D prints and 3D virtual models. Verbal protocol analysis examined critical thinking processes during collaborative student learning. Engagement was assessed via student feedback and a classroom observation protocol. Findings The findings demonstrated that digitized objects facilitated key critical thinking processes, particularly observation, problem finding, elaboration and evaluation. Student feedback was very positive and focused on strong interest in 3D technologies and the ability to engage in authentic exploration. Observations showed very high levels of on-task engagement. Research limitations/implications Additional research is necessary to determine if findings generalize across varied learner populations, including broader age ranges and socioeconomic samples, to activities implemented as fully online experiences and to digitized objects from varied domains. Originality/value Findings demonstrate digitized objects are effective methods to engage students in critical thinking and to promote engagement with authentic objects during classroom learning. Results demonstrate strong potential of new technologies to leverage the educational impact of digitized objects from local collections, setting the stage for expanded educational outreach by museums and libraries.
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Scheerlinck, Thierry, Elien De Winter, Amelie Sas, Sjoerd Kolk, Gert Van Gompel, and Jef Vandemeulebroucke. "Hip implants can restore anatomical and medialized rotation centres in most cases." Bone & Joint Open 2, no. 7 (2021): 476–85. http://dx.doi.org/10.1302/2633-1462.27.bjo-2021-0065.r1.
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Aims Hip arthroplasty does not always restore normal anatomy. This is due to inaccurate surgery or lack of stem sizes. We evaluated the aptitude of four total hip arthroplasty systems to restore an anatomical and medialized hip rotation centre. Methods Using 3D templating software in 49 CT scans of non-deformed femora, we virtually implanted: 1) small uncemented calcar-guided stems with two offset options (Optimys, Mathys), 2) uncemented straight stems with two offset options (Summit, DePuy Synthes), 3) cemented undersized stems (Exeter philosophy) with three offset options (CPT, ZimmerBiomet), and 4) cemented line-to-line stems (Kerboul philosophy) with proportional offsets (Centris, Mathys). We measured the distance between the templated and the anatomical and 5 mm medialized hip rotation centre. Results Both rotation centres could be restored within 5 mm in 94% and 92% of cases, respectively. The cemented undersized stem performed best, combining freedom of stem positioning and a large offset range. The uncemented straight stem performed well because of its large and well-chosen offset range, and despite the need for cortical bone contact limiting stem positioning. The cemented line-to-line stem performed less well due to a small range of sizes and offsets. The uncemented calcar-guided stem performed worst, despite 24 sizes and a large and well-chosen offset range. This was attributed to the calcar curvature restricting the stem insertion depth along the femoral axis. Conclusion In the majority of non-deformed femora, leg length, offset, and anteversion can be restored accurately with non-modular stems during 3D templating. Failure to restore hip biomechanics is mostly due to surgical inaccuracy. Small calcar guided stems offer no advantage to restore hip biomechanics compared to more traditional designs. Cite this article: Bone Jt Open 2021;2(7):476–485.
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Coatham, Samuel J., William I. Sellers, and Thomas A. Püschel. "Convex hull estimation of mammalian body segment parameters." Royal Society Open Science 8, no. 6 (2021): 210836. http://dx.doi.org/10.1098/rsos.210836.
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Obtaining accurate values for body segment parameters (BSPs) is fundamental in many biomechanical studies, particularly for gait analysis. Convex hulling, where the smallest-possible convex object that surrounds a set of points is calculated, has been suggested as an effective and time-efficient method to estimate these parameters in extinct animals, where soft tissues are rarely preserved. We investigated the effectiveness of convex hull BSP estimation in a range of extant mammals, to inform the potential future usage of this technique with extinct taxa. Computed tomography scans of both the skeleton and skin of every species investigated were virtually segmented. BSPs (the mass, position of the centre of mass and inertial tensors of each segment) were calculated from the resultant soft tissue segments, while the bone segments were used as the basis for convex hull reconstructions. We performed phylogenetic generalized least squares and ordinary least squares regressions to compare the BSPs calculated from soft tissue segments with those estimated using convex hulls, finding consistent predictive relationships for each body segment. The resultant regression equations can, therefore, be used with confidence in future volumetric reconstruction and biomechanical analyses of mammals, in both extinct and extant species where such data may not be available.
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Langley, Paul. "Establishing Practice Risk Management and Outcomes Claims for Medical Marijuana Dispensaries: Questions Legislators Should Ask." INNOVATIONS in pharmacy 10, no. 1 (2019): 1. http://dx.doi.org/10.24926/iip.v10i1.1596.
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In a previous commentary in INNOVATIONS in Pharmacy, the case was made that a major oversight in approving the establishment of medical marijuana programs through commercially and not-for-profit operated dispensaries is the failure to put in place standards for the monitoring and reporting of outcomes. It was pointed out that the evidence base is limited for the range of dosing options, administrative routes and conditions treated. The concern is that the ease that patients have in obtaining medical marijuana certification in many states means that a medical marijuana program is, in effect, little different from a recreational program. Dispensaries understandably focus on sales and returns to investors with scant attention given to tracking and reporting outcomes across the range of conditions and symptoms presented. While this no doubt appeals to investors in reducing administration costs, it makes it virtually impossible to deliver the appropriate and coordinated level of care that patients should expect if a medical marijuana dispensary is to meet it responsibilities in its duty of care. This places dispensaries at malpractice risk. Given this, this commentary focuses on the questions that legislators should ask in licensing medical marijuana dispensaries to ensure they meet a defensible duty of care to their patients.
 
 Article Type: Commentary
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Kolge, Neeraj Eknath, Vivek J. Patni, and Sheetal S. Potnis. "Tomographic mapping of buccal shelf area for optimum placement of bone screws: A three-dimensional cone-beam computed tomography evaluation." APOS Trends in Orthodontics 9 (December 31, 2019): 241–45. http://dx.doi.org/10.25259/apos_20_2019.
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Introduction: Buccal shelf bone screws have become increasingly popular as a preferred method of skeletal anchorage in the mandibular arch. Anatomic variations and clinical experience suggest that width and slope of the bone at buccal shelf vary in different population groups, with some individual variations. Aims and Objectives: The objective of this study was to evaluate angulation of the bone screw of mandibular buccal shelf area, total bone width, thickness of the cortical bone, and proximity to neurovascular structures. Materials and Methods: Cone-beam computed tomography scans were used to obtain measurements of the buccal shelf region of 35 patients (18 females, 17 males; mean age, 23.6 years). Measurements were taken at three locations (L1, L2, and L3) and total bone width was measured at two levels from the cementoenamel junction (CEJ, H1 and H2). Bone screws were virtually placed and their proximity evaluated from digitally traced inferior alveolar neurovascular bundle. Results: Permissible angulation for placement of buccal shelf bone screw considering the safety distance from the root and avoiding excessive buccal projection to minimize cheek irritation was found to be 74.48 (SD ± 4.26). Total bone width was maximum at the distobuccal cusp of mandibular second molar (L3H2; 6.40 ± 1.35) when measured at the level of 8 mm from the CEJ. Bone screws were well within the safety range from causing any iatrogenic damage to the inferior alveolar neurovascular bundle at all the three aforementioned locations. Conclusion: Thus, area buccal to the mandibular second molar region seems to be the most favorable site for placement of buccal shelf bone screws in Indian patients.
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Holub, Ashton S., Renee A. Bouley, Ruben C. Petreaca, and Aman Y. Husbands. "Identifying Cancer-Relevant Mutations in the DLC START Domain Using Evolutionary and Structure-Function Analyses." International Journal of Molecular Sciences 21, no. 21 (2020): 8175. http://dx.doi.org/10.3390/ijms21218175.
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Rho GTPase signaling promotes proliferation, invasion, and metastasis in a broad spectrum of cancers. Rho GTPase activity is regulated by the deleted in liver cancer (DLC) family of bona fide tumor suppressors which directly inactivate Rho GTPases by stimulating GTP hydrolysis. In addition to a RhoGAP domain, DLC proteins contain a StAR-related lipid transfer (START) domain. START domains in other organisms bind hydrophobic small molecules and can regulate interacting partners or co-occurring domains through a variety of mechanisms. In the case of DLC proteins, their START domain appears to contribute to tumor suppressive activity. However, the nature of this START-directed mechanism, as well as the identities of relevant functional residues, remain virtually unknown. Using the Catalogue of Somatic Mutations in Cancer (COSMIC) dataset and evolutionary and structure-function analyses, we identify several conserved residues likely to be required for START-directed regulation of DLC-1 and DLC-2 tumor-suppressive capabilities. This pan-cancer analysis shows that conserved residues of both START domains are highly overrepresented in cancer cells from a wide range tissues. Interestingly, in DLC-1 and DLC-2, three of these residues form multiple interactions at the tertiary structural level. Furthermore, mutation of any of these residues is predicted to disrupt interactions and thus destabilize the START domain. As such, these mutations would not have emerged from traditional hotspot scans of COSMIC. We propose that evolutionary and structure-function analyses are an underutilized strategy which could be used to unmask cancer-relevant mutations within COSMIC. Our data also suggest DLC-1 and DLC-2 as high-priority candidates for development of novel therapeutics that target their START domain.
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Dekker, Robert, and Milap Patel. "Outcomes of Surgical Treatment of Talar Osteochondral Lesions using Bone Marrow Aspirate and Microgenized Allograft Cartilage Extra-cellular Matrix." Foot & Ankle Orthopaedics 3, no. 3 (2018): 2473011418S0021. http://dx.doi.org/10.1177/2473011418s00210.
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Category: Sports Introduction/Purpose: Osteochondral lesions (OCL) of the talus are frequently seen after ankle injury and often result in significant morbidity. Apart from a single case report, we are the first to present a case series of OCLs treated with bone marrow aspirate and micronized extracellular allograft cartilage matrix designed to serve as a scaffold to promote autologous healing. Short to mid-term outcomes using this technique are virtually absent in the literature. In this study, we sought to assess pre- and post-procedural functional outcomes using the validated Patient Reported Outcomes Measurement Information System (PROMIS) as well as assess cartilage incorporation on postoperative ankle MRI using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring. Methods: Twelve patients with symptomatic talar OCLs (14 lesions) were prospectively recruited. Average age was 44 years. Each underwent ankle arthroscopy, ankle arthrotomy, marrow stimulation and lesion repair using BMA and micronized extracellular allograft cartilage matrix by a single fellowship trained foot and ankle Orthopedic Surgeon. Preoperative, 6 month and 1 year postoperative PROMIS pain and function scores were collected prospectively. At six months, all patients underwent ankle MRI scans that were reviewed by a fellowship trained musculoskeletal radiologist for MOCART scoring. Results: No significant difference was detected between mean pre- and postoperative PROMIS function (41.4 vs 38.1; p=.54) and pain (61.3 vs 66.1) scores at 6 months. No significant difference was seen between mean pre- and postoperative PROMIS function (41.4 vs 41.8; p=.93) and pain (61.3 vs 58; p=.48) scores at 1 year. Mean postoperative MOCART score was 53.2 with a range of 5 to 90. Conclusion: Bone marrow aspirate and extracellular allograft cartilage matrix for surgical treatment of talar OCL showed no statistically significant improvement in functional outcomes at 6 months and 1 year. No correlation between functional outcomes and MOCART score was seen.
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Arzoumanian, Varant, Bart Barlogie, Mauricio Pineda-Roman, et al. "Rapidly Cycled Aggressive Lymphoma-Like Therapy (HD-DTPACE) for Salvage of Patients with Advanced Multiple Myeloma (MM)." Blood 108, no. 11 (2006): 3561. http://dx.doi.org/10.1182/blood.v108.11.3561.3561.
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Abstract Background: High-dose melphalan (MEL)-based autotransplants (AT) have significantly improved complete response rates (CR) and survival in MM. We previously reported on DTPACE (Dexamethasone, Thalidomide, cis-Platin, Adriamycin, Cyclophosphamide, Etoposide) as a highly effective salvage regimen, although EFS and OS were short in the presence of cytogenetic abnormalities (CA) and elevated LDH. Hypothesizing that the 2–3mo recovery after MEL-AT permitted MM re-growth, we explored whether non-stem cell-toxic rapidly cycled dose-intensified DTPACE (HD-DTPACE) induced more sustained responses in AR-MM. Patients and Methods: 23 patients (median age, 58yr; range, 43–74) had high-risk features comprising CA, elevated LDH or high-risk gene expression profiles; 21 (91%) had progressed after AT(1, 4 pts; 2, 14 pts; 3, 3 pts); all had failed ≥1 line of salvage. HD-DTPACE comprised iv D 200mg/d and po T 200mg/d for 4–6d, and 4-day continuous infusions of P 15mg/m2/d, A 15mg/m2/d, C 600mg/m2/d and E 60mg/m2/d, which is an increase in D from 40mg to 200mg and 50% dose escalation of PACE. Results: 23 patients received 39 cycles of HD-DTPACE (1, 15 pts; 2, 3 pts; 3, 4 pts; 4, 1 pt); 18 (78%) responded (CR, 3; near-CR, 8, PR, 7). Focal lesions (FL) were present on PET-CT scans in 15 patients before therapy; after 1 cycle, the median FL decreased from 39 (range, 2–103) to 9 (range, 1–44); in 6 of 12 patients, extramedullary MM resolved. Thirteen patients subsequently received MEL- or BEAM-based AT; 7 received further consolidation and/or maintenance therapy. The tolerability of HD-DTPACE was underscored by its out-patient administration in 17 patients, only 3 of whom required subsequent admission. The median days to ANC> 500/ml and platelets>20.000/ml after the 1st cycle was 16 (range, 9–23) and 18 (range, 10–56). Prior to HD-DTPACE, 4 patients had compromised bone marrow reserve reflected by a platelet count <100,000/ml; however, only 1 required a PBSC boost. The median intervals between cycle 1–2, 2–3 and 3–4 were 41 days (range: 22–165), 39 days (range: 36–93), and 77 days respectively; 3 of 8 patients undergoing repeated cycles of HD-DTPACE had inter-cycle intervals of 22, 29 and 31 days, respectively, with excellent hematopoietic recovery. Consistent with the absence of hematopoietic stem cell injury, there was no evidence of cumulative thrombocytopenia. Non-hematological toxicities included colitis in 4 patients, although oral mucositis was virtually absent. Sepsis, CMV reactivation and DVT occurred in one patient each. Three patients died after HD-DTPACE (progressive disease n=2; cause unknown, n=1). While follow-up is short (median 4mo; range, 1–11), of the 33 patients, 11 remain event-free and 18 alive. Conclusion: HD-DTPACE is an effective, well-tolerated salvage regimen for AR-MM and could be cycled rapidly in heavily pre-treated patients. Rapid cycling of HD-DTPACE within 28 days will be evaluated up-front in patients with poor prognosis MM (CA, high LDH, high-risk genetics), whose 6-yr EFS and OS in our Total Therapy II trial was only 21% and 32%, respectively. Such approach has substantially advanced the outcome patients with aggressive, high-LDH lymphoma.
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Kanunnikova, O. M., V. V. Aksenova, B. E. Pushkarev, and V. I. Ladyanov. "Peculiarities of zinc coating corrosion in neutral environments with inhibitors based on benzotriazole, cyclohexylamine and morpholine." Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy, no. 3 (June 19, 2019): 55–67. http://dx.doi.org/10.17073/0021-3438-2019-3-55-67.
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The influence of domestic VNKh-L type nitrogen-containing corrosion inhibitors on the corrosion patterns of zinc coating on steel in a neutral environment was investigated. The paper aims to study the structure of the corroding zinc coating surface, as well as the influence of conditions simulating the degradation of inhibitors under actual application conditions on their protective properties. Mechanical activation in a ball planetary mill was used to simulate the thermal and deformation conditions of inhibitors. Zinc coating corrosion on steel was carried out in a sulfate-chloride environment simulating atmospheric corrosion and in borate buffer solution. The concentration of inhibitors in corrosion environments was 0,2 wt.%. The corroded surface morphology of the zinc coating was studied using the Philips SEM-515 scanning electron microscope (at an accelerating voltage of 10 kV) with an X-ray micro probe. Studies of the zinc coating corrosion rate on St 08 were carried out by the indirect measurement of corrosion resistance using the MONIKOR-1 corrosion meter. Borate buffer solution (Na2B4O7 + H3BO3, pH = 6,6) and the solution simulating atmospheric corrosion (NaCl + + Na2SO4, pH = 6,0) were used as corrosive environments. The corrosion rate of samples in corrosive environments without inhibitors was taken as 1. Exposure time of each sample in corrosive environments was 3 h. The chemical composition of corrosion products was studied by mirror reflection in the IR range. The IR spectra of metal plate surfaces were recorded on the FSM-1202 IR Fourier spectrometer in a wavelength range of 450–4000 cm–1 with a resolution of 2 cm–1 and an accumulation of 100 scans. A mirror reflection attachment with a 10° angle of incidence was used to obtain reflection spectra. The zinc coating corrosion rate in sulfate-chloride and borate environments in the presence of inhibitors based on benzotriazole and cyclohexylamine was virtually not reduced compared to the corrosion rate in the same environments without inhibitors. When both initial and mechanically activated inhibitors based on morpholine and benzotriazole are added to the corrosion environment, the iron corrosion rate decreases compared to the corrosion rate in the same environments without inhibitors. In the presence of initial and mechanically activated inhibitors of both groups, pitting corrosion of the zinc coating in the studied corrosion environments is observed. At the same time, the pitting depth under corrosion conditions is less than the zinc coating thickness.
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Cleveland, Danielle, Peter Stchur, Xiandeng Hou, Karl X. Yang, Jack Zhou, and Robert G. Michel. "Resonant Laser Ablation of Metals Detected by Atomic Emission in a Microwave Plasma and by Inductively Coupled Plasma Mass Spectrometry." Applied Spectroscopy 59, no. 12 (2005): 1427–44. http://dx.doi.org/10.1366/000370205775142656.
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It has been shown that an increase in sensitivity and selectivity of detection of an analyte can be achieved by tuning the ablation laser wavelength to match that of a resonant gas-phase transition of that analyte. This has been termed resonant laser ablation (RLA). For a pulsed tunable nanosecond laser, the data presented here illustrate the resonant enhancement effect in pure copper and aluminum samples, chromium oxide thin films, and for trace molybdenum in stainless steel samples, and indicate two main characteristics of the RLA phenomenon. The first is that there is an increase in the number of atoms ablated from the surface. The second is that the bandwidth of the wavelength dependence of the ablation is on the order of 1 nm. The effect was found to be virtually identical whether the atoms were detected by use of a microwave-induced plasma with atomic emission detection, by an inductively coupled plasma with mass spectrometric detection, or by observation of the number of laser pulses required to penetrate through thin films. The data indicate that a distinct ablation laser wavelength dependence exists, probably initiated via resonant radiation trapping, and accompanied by collisional broadening. Desorption contributions through radiation trapping are substantiated by changes in crater morphology as a function of wavelength and by the relatively broad linewidth of the ablation laser wavelength scans, compared to gas-phase excitation spectra. Also, other experiments with thin films demonstrate the existence of a distinct laser–material interaction and suggest that a combination of desorption induced by electronic transition (DIET) with resonant radiation trapping could assist in the enhancement of desorption yields. These results were obtained by a detailed inspection of the effect of the wavelength of the ablation laser over a narrow range of energy densities that lie between the threshold of laser-induced desorption of species and the usual analytical ablation regime. Normal ablation employs high-power lasers in an attempt to create a vapor plume without selective vaporization, and with a stoichiometry that accurately represents the stoichiometry of species in the solid sample. RLA, as a method of selective vaporization, appears to provide an opportunity to exploit selective vaporization in new ways.
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Injerd, Russell, Kristen Burnham, Matthew Walb, Bruce Hershatter, Sagar A. Patel, and Benjamin Walker Fischer-Valuck. "Normal tissue complication probabilities (NTCP) of urethral stricture following salvage SBRT or HDR for periurethral recurrences following prior definitive radiation therapy." Journal of Clinical Oncology 39, no. 6_suppl (2021): 246. http://dx.doi.org/10.1200/jco.2021.39.6_suppl.246.
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246 Background: SBRT and HDR brachytherapy have emerged as definitive salvage re-irradiation options for men with locally recurrent prostate cancer after prior radiation therapy (RT). Toxicity with re-irradiation remains a concern in this setting, particularly for salvage of periurethral recurrences. We calculated the normal tissue complication probability (NTCP) of urethral stricture following salvage re-irradiation (HDR and SBRT) after previous definitive RT (external beam or HDR) for periurethral recurrences. Methods: Two upfront definitive treatment plans were generated for 5 men with localized prostate cancer: External Beam RT (EBRT1) to a dose of 79.2 Gy in 1.8 Gy fractions and HDR monotherapy (HDR1), 13.5 Gy x 2 implants. Periurethral recurrences were virtually created on diagnostic MRI scans for each of the five men and defined as a recurrent dominant intraprostatic lesion (DIL). Three salvage RT plans were generated for each patient (constraints in Table): HDR salvage (10 Gy whole gland; 13.5 Gy to DIL; 2 implants), SBRTr with maximal rectal sparing (constraints designed for salvage following prior EBRT; 30 Gy in 5 fractions whole gland; 40 Gy in 5 fractions to DIL), and SBRTu with maximal urethral sparing (constraints designed for patients with prior HDR monotherapy; same Rx). DVH data was collected for each plan (previous RT and each salvage approach) and the equivalent uniform dose (EUD) was calculated. NTCP for the urethral stricture in the summed plans (prior definitive treatment + each salvage plan) was calculated by the Lyman-Kutcher-Burman model using the following parameters: (α/β = 5Gy; TD50= 116.7; m = 0.23; n = 0.3). Results: Prescription coverage of 90% of the DIL volume was achieved for each plan. The mean NTCP of urethral stricture for EBRT1 + HDR salvage was 55.2% (range, 52.2-59.1%) and for HDR1 + HDR salvage was 49.2% (42.9-57.5%). For EBRT1 + SBRTr and EBRT1 + SBRTu the NTCP for urethral stricture was 54.0% (50.4-61.0%) and 43.2% (39.4-48.4%), respectively. The NTCP of urethral stricture for HDR1 + SBRTr was 48.1% (41.0-57.2%) and for HDR1 + SBRTu was 37.6% (30.9-44.6%). Conclusions: In this modeling analysis of salvage RT for periurethral recurrences following previous RT (EBRT or HDR monotherapy), the NTCP for urethral stricture was numerically lowest for salvage SBRT using maximum urethral sparing dose constraints in comparison to salvage SBRT with maximum rectal sparing constraints or salvage HDR brachytherapy. This type of analysis lends insight into personalized treatment planning based on previous RT modality and previous dose to organs at risk. Expanded analysis is underway. [Table: see text]
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Lakhotia, Rahul, Christopher Melani, Stefania Pittaluga, et al. "Circulating Tumor DNA Dynamics during Therapy Predict Outcomes in Mantle Cell Lymphoma." Blood 132, Supplement 1 (2018): 147. http://dx.doi.org/10.1182/blood-2018-99-112573.
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Abstract Background: Mantle cell lymphoma (MCL) is an incurable B-cell lymphoma with striking variability in tumor biology and clinical behavior across patients. Noninvasive blood-based biomarkers that monitor disease and treatment response may guide clinical decisions throughout disease course. Circulating tumor DNA (ctDNA) is a highly tumor-specific biomarker detectable in the blood of virtually all MCL patients. Within a prospective clinical trial, we studied Adaptive's next-generation sequencing assay to detect and quantify ctDNA in serum throughout therapy. Previously, we reported that ctDNA clearance after induction predicts both PFS and OS (Roschewski et al. ASCO 2018). Bortezomib (BZ) is a proteasome inhibitor shown to improve PFS when added to combination chemotherapy (Robak et al. N Eng J Med 2015). Herein, we analyze the clinical significance of ctDNA dynamics during therapy in patients treated with BZ + DA-EPOCH-R without consolidation. Methods: Untreated MCL patients received BZ monotherapy x 1 cycle then induction with BZ + DA-EPOCH-R up to 6 cycles. After induction, patients were randomized to observation vs. BZ maintenance x 18m. Patients had serum prospectively collected pre-Tx, after BZ monotherapy, before each cycle, after induction, and with each surveillance visit. Surveillance visits were paired with CT scans q4mos x 2y, q6mos in years 2-4, then annually. Pre-treatment specimens (FFPE or frozen cells) were analyzed for tumor-specific clonotypes. Tumor DNA was amplified using locus-specific primer sets for the Ig heavy-chain and light-chain loci, CCND1, and BCL2 translocations. Amplified products were sequenced, and patients without a high-frequency tumor clonotype were excluded. Levels of ctDNA at baseline, after BZ monotherapy, and after 1, 2 cycles of induction were analyzed. Results: 53 untreated MCL patients received BZ + DA-EPOCH-R between September 2005 and January 2016. After median potential f/u of 10y, median PFS is 29.3m and the 5-yr OS is 78.2%. BZ maintenance had no impact on PFS or OS. Of 52 patients w/available biopsies, 50 (96%) had a tumor-specific clonotype identified. Of 48 patients w/pre-treatment serum, 46 (96%) had detectable ctDNA. ctDNA was successfully tracked in 625 of 647 (97%) serum samples. The median level of baseline ctDNA was 742.98 cell equivalents/mL (range 0 to 101,008.58). Baseline ctDNA correlated with total metabolic tumor volume on PET scan (rs=0.74) but was not associated with PFS (p=0.45) or OS (p=0.22). Of 42 patients who received BZ monotherapy, 26 (62%) had decreases in ctDNA, 15 (36%) had increases, and 1 (2%) had no change. The median absolute decrease in ctDNA was 35 cell equivalents/ml (range -20,901 to +6,667) and the median relative decrease was 24% (range -100% to +530%). Notably, lower absolute ctDNA levels after BZ window were associated with improved PFS compared to patients with ctDNA above the median (34m vs 22m, p=0.02)(Figure 1). Clearance of ctDNA after 1 cycle of DA-EPOCH-R + BZ was strongly associated with a superior median PFS (76.4m vs 20.7m, p=0.0037)(Figure 2) and a trend towards superior 4-yr OS (92.3% vs 73.0%, p=0.23). Clearance of ctDNA after 2 cycles of DA-EPOCH-R + BZ was also associated with a superior median PFS (32.4m vs 21.4m, p=0.015) and a trend towards superior median OS (82.2m vs 73.2m, p=0.15). Conclusions: Circulating tumor DNA is detectable in nearly all patients with MCL. Dynamic changes that occur very early during therapy may predict clinical outcomes and may be an early readout for the activity of targeted agents. Given its broad applicability, ctDNA should be prospectively studied as part of response-adapted approaches in MCL. This work was supported by the Intramural Research Program of NCI and Adaptive Biotechnologies, Inc. Disclosures Jacob: Adaptive Biotechnologies: Employment, Equity Ownership. Yusko:Adaptive Biotechnologies: Employment, Equity Ownership. Wiestner:Pharmacyclics LLC, an AbbVie Company: Research Funding.
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Roschewski, Mark, Marc A. Weniger, Delong Liu, et al. "FDG-PET SUV Correlates with Expression of Genes Reflecting Proliferation, Metabolism, and Oncogene Activity in Mantle Cell Lymphoma (MCL),." Blood 118, no. 21 (2011): 3670. http://dx.doi.org/10.1182/blood.v118.21.3670.3670.
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Abstract Abstract 3670 Background: Mantle cell lymphoma (MCL) is a biologically heterogeneous disease with marked variation in clinical behavior. Tumor proliferation on gene expression profiling (GEP) is prognostic in MCL but is not available to the clinician. The % of Ki-67 expressing cells correlates with proliferation, but the test suffers inter-observer variability. We previously reported that SUV on FDG PET correlates to the tumor proliferation score (PS), the % Ki67 positive cells, and serum LDH levels in untreated MCL (Roschewski ASH 2010). Here, we expand this investigation to a larger cohort and present results of gene expression analysis of MCL lymph node biopsies in relation to FDG uptake. Methods: Untreated MCL patients underwent baseline PET/CT followed by a nodal biopsy. Analysis of the PET/CT scans was done by two experts in nuclear medicine who were blinded to the outcome of the patients and pathology findings. SUVnode and SUVmax normalized to body weight were recorded. For MCL patients, the expression of 18 proliferation signature genes were averaged to generate a PS as previously described (Rosenwald Cancer Cell 2003). The %Ki67 staining was calculated using computer-based image analysis software and recorded as the number of positive cells/total number of cells. Serum LDH on the day of treatment was recorded. Gene expression between tumor with high (> 5 SUVnode) and low (< 5 SUVnode) FDG uptake was compared. Gene expression and SUV as a continuous variable were also analyzed by Spearman correlation. Results: 41 MCL patients were evaluated between September 2005 and March 2011. Median age was 58 years (41–73) and 78% of patients were male. All patients were stage IV and MIPI risk groups included 21 low, 15 intermediate and 5 high. PET/CT scans were available in 39, biopsies in 28, and adequate RNA for GEP in 27. The median SUVnode was 4.94 (1.81–12.89) and the median SUVmax 6.40 (2.22–17.5). SUVnode and SUVmax had virtually identical correlations to PS: r=0.45 (p < 0.016) and r=0.46 (p < 0.015). % Ki67 in MCL lymph node biopsies correlated with both SUVnode, r=0.58 (p < 0.002) and PS, r=0.59 (p < 0.001). LDH correlated with PS, r=0.55 (p < 0.002) but less so with SUVmax, r=0.35 (p < 0.03). We sought to determine which cellular processes correlate best with FDG avidity. We first separated MCL biopsies into two groups using the median SUV node. 88 probesets representing 79 genes were differentially expressed with a fold change ≥ 2. Of 32 upregulated genes, 14 were associated with cell proliferation and in Ingenuity Pathway analysis (IPA) the top network was cellular growth and proliferation. Next, we used Spearman correlation to better represent the full dynamic range of the FDG-PET measurement. 69 probesets genes were identified (FDR < 0.2) representing 61 genes, 47 of which were positively correlated with SUV PET. A key network function of these genes by IPA was carbohydrate and lipid metabolism. Among the genes with the highest correlation with SUV PET (rho > 0.72, p < 0.0001) were two members of the RAS Oncogene family: KRAS and RAB11A. There was also a remarkable representation of genes involved in protein homeostasis including PSMB5 that encodes the 26S proteasome subunit carrying the chymotrypsin like activity, Hsp40-family chaperones, and an ubiquitin conjugating enzyme (UBE2S). Finally, PRMT5 a protein arginine methyltransferase that has been shown to cooperate with cyclin D1 in promoting tumor growth also showed a high correlation with FDG-PET (rho = 0.65, p = 0.002). Conclusions: High FDG PET SUVs are typically seen in the quartile of patients with the highest tumor proliferation. Across all patients increasing SUV values correlate well with increased metabolism that intriguingly also includes the ubiquitin-proteasome system and PSMB5, the target of bortezomib. Thus, FDG PET might have some correlation with response to bortezomib treatment and should be further studied in this context. FDG PET integrates measures of proliferation and cellular metabolism and reflects disease specific activity of oncogenic pathways. Disclosures: No relevant conflicts of interest to declare.
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Zhurabekova, Gulmira, and Merey Merey. "NEUROIMAGING DATA OF THE STUDY OF THE CHIASMAL-SELLAR REGION STRUCTURES." Ambiance in Life International Scientific Journal in Medicine of Southern Caucasus 06, no. 01 (2021): 6–8. http://dx.doi.org/10.36962/0601202106.
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Background: Sphenoid sinus (SS) is separated by a septum with various position, therefore sizes of two sinus cavities are variable [2]. In addition, sphenoid sinus differs in pneumatization type, ranging from its absence to extensive forms.Knowledge of the linear size and shape of the skull, the structure of the sphenoid sinus and its interconnection with nearby structures will help to avoid complications when performing surgical endoscopic interventions in the chiasmal-sellar region. Currently, the transsphenoid approach is the most optimal in neurosurgery for intracellar and cranial pathologies treatment. Due to proximity and anatomical interconnection of sphenoid sinus with other anatomical structures, such as anterior knees of intracavernous segments of internal carotid artery (ICA), optic nerve (ON), there is a high risk of complications during surgery [1,2,3,4]. Purpose: Features of skull craniometric parameters, the type sphenoid sinus pneumatization, and its practical value in various ON and ICA positions. Methods: The retrospective research, using magnetic resonance imaging (MRI) scans of head, included 1111 people, with 410 males and 701 females out of them but the scope of the article is limited to 93 of them, including 34 males (37%) and 59 females (63%) aged from 20 to 71 years. The research design complies with the Helsinki Declaration’s provisions and was approved by the Local Ethics Committee of the West Kazakhstan Medical University named after Marat Ospanov №50 from January 17, 2020. The average age of males was 41.6 (20 – 71 years), and for females was 41.7 (20 – 66 years). Inclusion criteria were as the following: 1) age range from 20 to 71 years, 2) patients living in Aktobe region, 3) patients sent for examination with pituitary (hypophysis) pathology, 5) patients referred with CSR vascular pathology, 6) patients referred for verification of CSR pathology diagnosis. Exclusion criteria were as the following: 1) patients with skull bones fractures, 2) patients after skull trepanation, 3) patients having orthodontic and orthognathic research at examination time, 4) patients with congenital skull malformations, having gross skull deformation, 5) patients with brain tumors and hemorrhages with obvious CSR compression at examination time, 6) pregnancy, lactation, long-term use of hormonal drugs by persons of both gender. With the RadiAnt Dicom Viewer 5.5.1 program measured craniological indices: crosslongitudinal skull index, degree of pneumatization of the sphenoidal sinus; protrusion and/or gaping of internal carotid artery canal and optic nerve.Allstatistical analyses were performed using Statistica 8.0. Results: The data we obtained show that the vast majority of older males (60-80 years old) had mesocrane skull shape, in contrast to females, among whom the frequency of brachycrane skull shape prevails. Among 20-40 years aged males, the highest percentage falls on mesocrane skull form, while in females the frequencies of mesocrane and brachycrane skull forms are relatively the same. In males and females with ages of 40-60 years, mesocrane and brachycranean skull forms are almost half of the total number of cases. An interesting fact was that dolichocranous skull shape is absolutely not found in both males and females of 40-80 years old age. The skull structure distribution by gender. Based on the sphenoid sinus types classification by Ossama & Guldner, our research revealed that there is no Conchal type (type I) in both genders. In 20-40 age, type III prevailed among males, while type IV has a maximum among females. Types III and IV predominated among males and females of 40-60 years old age. In 60-80 years category, type III prevails among females, while males have two times less. Type II is absent among 40-60 aged males and 60-80 aged females. As per the research of anatomical structures close to SS, it was found that ON and ICA canals form protrusions on the inner surface of the sphenoid sinus sidewall. The protrusion degree was ranged from a slight depression on the lateral wall to a complete "immersion" of canals into the sinus. No protrusion of ON and ICA canals were found in 60-80 years old males in 80% of cases, while complete absence of protrusion was shown in case of the same age females. However, protrusion of only the ICA canal occurs in 60% of cases with over 60 years old age females, while the same was in only 20% with the same age males. There was no case of ON canal protrusion in males, but ON canal gave a protrusion in sphenoid sinus wall in 49% of 20-40 years old females. ON and ICA canals protrusion in 20-60 years old males was found in about 30%, and the same protrusion was found in 60-80 years old females in 40%. Conclusions: This study is aimed at identifying the features of structure of the sphenoidal sinus, focusing on the absence of a dolichocrane type of skull among the population, on the clear distinction between men and women by the type of skull structure and the features of pneumatization of the sphenoidal sinus. The presellar type of sphenoidal sinus has a virtually low adherence to changes in sinus canals in types II and IV. Thus, careful planning of trans-sphenoid access to the sella is possible with modern imaging methods. Different anatomical variations can be detected so that problems can be predicted to be assessable. In order to avoid morbid consequences during surgery, it is imperative that clinicians determine the location and extent of sphenoid sinus walls and its relation to adjacent vital structures whenever trans-sphenoid pituitary surgery is expected. The few surgical tips related to sphenoid sinus anatomical configuration are important to keep in mind during such an approach. Keywords: MRI; sphenoid sinus; pneumatization; internal carotid artery; optic nerve
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Palanca, Marco, Gianluca Tozzi, Luca Cristofolini, Marco Viceconti, and Enrico Dall'Ara. "Three-Dimensional Local Measurements of Bone Strain and Displacement: Comparison of Three Digital Volume Correlation Approaches." Journal of Biomechanical Engineering 137, no. 7 (2015). http://dx.doi.org/10.1115/1.4030174.
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Different digital volume correlation (DVC) approaches are currently available or under development for bone tissue micromechanics. The aim of this study was to compare accuracy and precision errors of three DVC approaches for a particular three-dimensional (3D) zero-strain condition. Trabecular and cortical bone specimens were repeatedly scanned with a micro-computed tomography (CT). The errors affecting computed displacements and strains were extracted for a known virtual translation, as well as for repeated scans. Three DVC strategies were tested: two local approaches, based on fast-Fourier-transform (DaVis-FFT) or direct-correlation (DaVis-DC), and a global approach based on elastic registration and a finite element (FE) solver (ShIRT-FE). Different computation subvolume sizes were tested. Much larger errors were found for the repeated scans than for the virtual translation test. For each algorithm, errors decreased asymptotically for larger subvolume sizes in the range explored. Considering this particular set of images, ShIRT-FE showed an overall better accuracy and precision (a few hundreds microstrain for a subvolume of 50 voxels). When the largest subvolume (50–52 voxels) was applied to cortical bone, the accuracy error obtained for repeated scans with ShIRT-FE was approximately half of that for the best local approach (DaVis-DC). The difference was lower (250 microstrain) in the case of trabecular bone. In terms of precision, the errors shown by DaVis-DC were closer to the ones computed by ShIRT-FE (differences of 131 microstrain and 157 microstrain for cortical and trabecular bone, respectively). The multipass computation available for DaVis software improved the accuracy and precision only for the DaVis-FFT in the virtual translation, particularly for trabecular bone. The better accuracy and precision of ShIRT-FE, followed by DaVis-DC, were obtained with a higher computational cost when compared to DaVis-FFT. The results underline the importance of performing a quantitative comparison of DVC methods on the same set of samples by using also repeated scans, other than virtual translation tests only. ShIRT-FE provides the most accurate and precise results for this set of images. However, both DaVis approaches show reasonable results for large nodal spacing, particularly for trabecular bone. Finally, this study highlights the importance of using sufficiently large subvolumes, in order to achieve better accuracy and precision.
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Custódio, Antônio Luís Neto, Andrew Cameron, Mahmoud Bakr, Chris Little, Bruno Ramos Chrcanovic, and Peter Reher. "Positioning accuracy assessment of minimally invasive percutaneous injection techniques for the treatment of temporomandibular disorders." Dentomaxillofacial Radiology, July 24, 2020, 20200313. http://dx.doi.org/10.1259/dmfr.20200313.
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Objective: The aim of the present study was to evaluate the accuracy of an extraoral CBCT-planned 3D-printed surgical guide aimed to percutaneous injection of substances into the temporomandibular joint (TMJ) and the lateral pterygoid muscle (LPM). Methods: Nine human cadaver heads were used. Pre-planning CBCT and facial scans were obtained and three percutaneous injection sites were planned: one for the lower compartment of the TMJ and two for the LPM. A digital surgical guide was then designed with small titanium sleeves and printed by a 3D printer. After the injections, new CBCT scans with the needles in place were obtained in order to assess the accuracy of the procedure in relation to the virtual planning. Results: The mean values for angle deviation were very low (range 1.13o-4.08o), the same happening for the mean difference in the length reached (range 1.82–2.64 mm), as well as for the mean difference in the needle tip dislocation (range 0.94–2.03 mm). Conclusion: The guide seems to be a reliable tool for accurate percutaneous injection of drugs into the inferior compartment of the TMJ and the LPM. Further studies are necessary to test the efficacy and validate the method in an in vivo study.