The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform
Michael A. King - One of the best experts on this subject based on the ideXlab platform.
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Comparison study of temporal regularization methods for fully 5D reconstruction of Cardiac Gated dynamic SPECT
Physics in medicine and biology, 2012Co-Authors: Xiaofeng Niu, Yongyi Yang, Michael A. KingAbstract:Temporal regularization plays a critical role in Cardiac Gated dynamic SPECT reconstruction, of which the goal is to obtain an image sequence from a single acquisition which simultaneously shows both Cardiac motion and tracer distribution change over the course of Imaging (termed 5D). In our recent work, we explored two different approaches for temporal regularization of the dynamic activities in Gated dynamic reconstruction without the use of fast camera rotation: one is the dynamic EM (dEM) approach which is imposed on the temporal trend of the time activity of each voxel, and the other is a B-spline modeling approach in which the time activity is regulated by a set of B-spline basis functions. In this work, we extend the B-spline approach to fully 5D reconstruction and conduct a thorough quantitative comparison with the dEM approach. In the evaluation of the reconstruction results, we apply a number of quantitative measures on two major aspects of the reconstructed dynamic images: (1) the accuracy of the reconstructed activity distribution in the myocardium and (2) the ability of the reconstructed dynamic activities to differentiate perfusion defects from normal myocardial wall uptake. These measures include the mean square error (MSE), bias-variance analysis, accuracy of time-activity curves (TAC), contrast-to-noise ratio of a defect, composite kinetic map of the left ventricle wall and perfusion defect detectability with channelized Hotelling observer. In experiments, we simulated Cardiac Gated Imaging with the NURBS-based Cardiac-torso phantom and Tc99m-Teboroxime as the Imaging agent, where acquisition with the equivalent of only three full camera rotations was used during the Imaging period. The results show that both dEM and B-spline 5D could achieve similar overall accuracy in the myocardium in terms of MSE. However, compared to dEM 5D, the B-spline approach could achieve a more accurate reconstruction of the voxel TACs; in particular, B-spline 5D could achieve a much smaller bias level in the early uptake stage of the Imaging period. Furthermore, it could allow better separation of the perfusion defect from the normal at both the early and the late stages of the Imaging period.
Grigorios Korosoglou - One of the best experts on this subject based on the ideXlab platform.
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Multimodality Cardiac computed tomography angiography and magnetic resonance with clinical-grade scanners provide robust assessment of Cardiac morphology and function in rabbits
Journal of thoracic disease, 2019Co-Authors: Gitsios Gitsioudis, Maximilian Nunninger, Anna Missiou, Peter Wolf, Hugo A. Katus, Grigorios KorosoglouAbstract:Background Non-invasive computer tomography (CT)- and magnetic resonance (MR)-based Cardiac Imaging still remains challenging in rodents. To investigate the robustness of non-invasive multimodality Cardiac Imaging in rabbits using clinical-grade CT and MR scanners. Methods A total of 16 rabbits (2.7-4.0 kg) serially underwent Cardiac-Gated Imaging using a clinical-grade 256-row CT and a 1.5 Tesla MR-scanner at baseline and at 4-month follow-up (16±1 weeks). Image analysis included image quality (5-grade scale), left ventricular (LV) volumes, LV stroke volume, LV diameters, LV wall thickness and ejection fraction (LVEF). Results Cardiac MR (CMR) and CT angiography (CTA) provide images with an overall good image quality (excellent or good quality: CMR 82% vs. CTA 78%, P=0.68). Linear regression analysis demonstrated a good correlation of all diameters (diam.) and volumes (vol.) as assessed by CTA and CMR (diam.: r=0.9, 95% CI: 0.8-0.9; vol.: r=0.8, 95% CI: 0.6-0.9; P
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Multimodality Cardiac computed tomography angiography and magnetic resonance with clinical-grade scanners provide robust assessment of Cardiac morphology and function in rabbits.
Journal of thoracic disease, 2019Co-Authors: Gitsios Gitsioudis, Maximilian Nunninger, Anna Missiou, Peter Wolf, Hugo A. Katus, Grigorios KorosoglouAbstract:Background: Non-invasive computer tomography (CT)- and magnetic resonance (MR)-based Cardiac Imaging still remains challenging in rodents. To investigate the robustness of non-invasive multimodality Cardiac Imaging in rabbits using clinical-grade CT and MR scanners. Methods: A total of 16 rabbits (2.7–4.0 kg) serially underwent Cardiac-Gated Imaging using a clinical-grade 256-row CT and a 1.5 Tesla MR-scanner at baseline and at 4-month follow-up (16±1 weeks). Image analysis included image quality (5-grade scale), left ventricular (LV) volumes, LV stroke volume, LV diameters, LV wall thickness and ejection fraction (LVEF). Results: Cardiac MR (CMR) and CT angiography (CTA) provide images with an overall good image quality (excellent or good quality: CMR 82% vs. CTA 78%, P=0.68). Linear regression analysis demonstrated a good correlation of all diameters (diam.) and volumes (vol.) as assessed by CTA and CMR (diam.: r=0.9, 95% CI: 0.8–0.9; vol.: r=0.8, 95% CI: 0.6–0.9; P Conclusions: Multimodality non-invasive assessment of Cardiac function and aortic hemodynamics is feasible and robust in rabbits using clinical-grade and MR and CT scanners. These Imaging modalities could improve serial Cardiac assessment for disease monitoring in preclinical settings.
Moise Danielpour - One of the best experts on this subject based on the ideXlab platform.
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True FISP Cardiac Gated CSF Flow Dynamic Imaging of Chiari Malformation
Neurosurgery, 2019Co-Authors: Alon Kashanian, Moise DanielpourAbstract:Abstract INTRODUCTION Brain pulsation and related CSF dynamics is a well-known intraoperative characteristic, but methods for its visualization on magnetic resonance Imaging (MRI) have until now been very limited. Best characterized techniques including phase-contrast MRI and cine echo-planar Imaging, although of significant value, lack a detailed spatial and temporal resolution needed to investigate CSF and structural dynamics in an adequate manner to address preoperative decision making. Electrocardiographic (ECG)-Gated true fast Imaging with steady-state precession (FISP) sequences has been widely used to investigate Cardiac motion and is capable of demonstrating brain pulsations and movements of intracranial structures surrounded by CSF with high temporal and spatial precision. We feature here the application of true FISP Cardiac-Gated Imaging to the management of 2 patients with Chiari Malformation Type 1 and associated syringohydromyelia. METHODS Two children with Chiari Malformation Type 1 and concurrent syringohydromyelia underwent true FISP Cardiac-Gated Imaging at our institution. RESULTS While conventional Imaging studies such as T1 and phase-contrast cine MRI appeared to demonstrate obstruction of CSF flow secondary to tonsillar herniation, true FISP showed patent peritonsillar CSF flow and the presence of a pulsatile arachnoid veil. Subsequently, open surgery confirmed the presence of an arachnoid veil, and postoperative true FISP Imaging revealed restoration of CSF flow following arachnoid veil fenestration. CONCLUSION We demonstrated 2 patients who presented with Chiari 1 malformation, where true FISP Cardiac Imaging was very instructive in visualizing dynamic images of an arachnoid veil and its possible role in the development of syringomyelia without a significant obstruction of outflow by cerebellar tonsils at the foramen of Magendie. We advocate use of this technology will aid in pre and post-surgical decision making, providing a more representative image of posterior fossa pathology in patients with Chiari 1 malformation.
Xiaofeng Niu - One of the best experts on this subject based on the ideXlab platform.
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Comparison study of temporal regularization methods for fully 5D reconstruction of Cardiac Gated dynamic SPECT
Physics in medicine and biology, 2012Co-Authors: Xiaofeng Niu, Yongyi Yang, Michael A. KingAbstract:Temporal regularization plays a critical role in Cardiac Gated dynamic SPECT reconstruction, of which the goal is to obtain an image sequence from a single acquisition which simultaneously shows both Cardiac motion and tracer distribution change over the course of Imaging (termed 5D). In our recent work, we explored two different approaches for temporal regularization of the dynamic activities in Gated dynamic reconstruction without the use of fast camera rotation: one is the dynamic EM (dEM) approach which is imposed on the temporal trend of the time activity of each voxel, and the other is a B-spline modeling approach in which the time activity is regulated by a set of B-spline basis functions. In this work, we extend the B-spline approach to fully 5D reconstruction and conduct a thorough quantitative comparison with the dEM approach. In the evaluation of the reconstruction results, we apply a number of quantitative measures on two major aspects of the reconstructed dynamic images: (1) the accuracy of the reconstructed activity distribution in the myocardium and (2) the ability of the reconstructed dynamic activities to differentiate perfusion defects from normal myocardial wall uptake. These measures include the mean square error (MSE), bias-variance analysis, accuracy of time-activity curves (TAC), contrast-to-noise ratio of a defect, composite kinetic map of the left ventricle wall and perfusion defect detectability with channelized Hotelling observer. In experiments, we simulated Cardiac Gated Imaging with the NURBS-based Cardiac-torso phantom and Tc99m-Teboroxime as the Imaging agent, where acquisition with the equivalent of only three full camera rotations was used during the Imaging period. The results show that both dEM and B-spline 5D could achieve similar overall accuracy in the myocardium in terms of MSE. However, compared to dEM 5D, the B-spline approach could achieve a more accurate reconstruction of the voxel TACs; in particular, B-spline 5D could achieve a much smaller bias level in the early uptake stage of the Imaging period. Furthermore, it could allow better separation of the perfusion defect from the normal at both the early and the late stages of the Imaging period.
Gitsios Gitsioudis - One of the best experts on this subject based on the ideXlab platform.
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Multimodality Cardiac computed tomography angiography and magnetic resonance with clinical-grade scanners provide robust assessment of Cardiac morphology and function in rabbits
Journal of thoracic disease, 2019Co-Authors: Gitsios Gitsioudis, Maximilian Nunninger, Anna Missiou, Peter Wolf, Hugo A. Katus, Grigorios KorosoglouAbstract:Background Non-invasive computer tomography (CT)- and magnetic resonance (MR)-based Cardiac Imaging still remains challenging in rodents. To investigate the robustness of non-invasive multimodality Cardiac Imaging in rabbits using clinical-grade CT and MR scanners. Methods A total of 16 rabbits (2.7-4.0 kg) serially underwent Cardiac-Gated Imaging using a clinical-grade 256-row CT and a 1.5 Tesla MR-scanner at baseline and at 4-month follow-up (16±1 weeks). Image analysis included image quality (5-grade scale), left ventricular (LV) volumes, LV stroke volume, LV diameters, LV wall thickness and ejection fraction (LVEF). Results Cardiac MR (CMR) and CT angiography (CTA) provide images with an overall good image quality (excellent or good quality: CMR 82% vs. CTA 78%, P=0.68). Linear regression analysis demonstrated a good correlation of all diameters (diam.) and volumes (vol.) as assessed by CTA and CMR (diam.: r=0.9, 95% CI: 0.8-0.9; vol.: r=0.8, 95% CI: 0.6-0.9; P
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Multimodality Cardiac computed tomography angiography and magnetic resonance with clinical-grade scanners provide robust assessment of Cardiac morphology and function in rabbits.
Journal of thoracic disease, 2019Co-Authors: Gitsios Gitsioudis, Maximilian Nunninger, Anna Missiou, Peter Wolf, Hugo A. Katus, Grigorios KorosoglouAbstract:Background: Non-invasive computer tomography (CT)- and magnetic resonance (MR)-based Cardiac Imaging still remains challenging in rodents. To investigate the robustness of non-invasive multimodality Cardiac Imaging in rabbits using clinical-grade CT and MR scanners. Methods: A total of 16 rabbits (2.7–4.0 kg) serially underwent Cardiac-Gated Imaging using a clinical-grade 256-row CT and a 1.5 Tesla MR-scanner at baseline and at 4-month follow-up (16±1 weeks). Image analysis included image quality (5-grade scale), left ventricular (LV) volumes, LV stroke volume, LV diameters, LV wall thickness and ejection fraction (LVEF). Results: Cardiac MR (CMR) and CT angiography (CTA) provide images with an overall good image quality (excellent or good quality: CMR 82% vs. CTA 78%, P=0.68). Linear regression analysis demonstrated a good correlation of all diameters (diam.) and volumes (vol.) as assessed by CTA and CMR (diam.: r=0.9, 95% CI: 0.8–0.9; vol.: r=0.8, 95% CI: 0.6–0.9; P Conclusions: Multimodality non-invasive assessment of Cardiac function and aortic hemodynamics is feasible and robust in rabbits using clinical-grade and MR and CT scanners. These Imaging modalities could improve serial Cardiac assessment for disease monitoring in preclinical settings.