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Artery Motion (artery + motion)

Distribution by Scientific Domains
Medical Sciences60%

Selected Abstracts

Hemodynamic analysis of intracranial aneurysms with moving parent arteries: Basilar tip aneurysms

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 10 2010
Daniel M. Sforza
Abstract The effects of parent artery motion on the hemodynamics of basilar tip saccular aneurysms and its potential effect on aneurysm rupture were studied. The aneurysm and parent artery motions in two patients were determined from cine loops of dynamic angiographies. The oscillatory motion amplitude was quantified by registering the frames. Patient-specific computational fluid dynamics (CFD) models of both aneurysms were constructed from 3D rotational angiography images. Two CFD calculations were performed for each patient, corresponding to static and moving models. The motion estimated from the dynamic images was used to move the surface grid points in the moving model. Visualizations from the simulations were compared for wall shear stress (WSS), velocity profiles, and streamlines. In both patients, a rigid oscillation of the aneurysm and basilar artery in the anterio-posterior direction was observed and measured. The distribution of WSS was nearly identical between the models of each patient, as well as major intra-aneurysmal flow structures, inflow jets, and regions of impingement. The motion observed in pulsating intracranial vasculature does not have a major impact on intra-aneurysmal hemodynamic variables. Parent artery motion is unlikely to be a risk factor for increased risk of aneurysmal rupture. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Correction for heart rate variability during 3D whole heart MR coronary angiography

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2008
Stijntje D. Roes MD
Abstract Purpose To evaluate the effect of a real-time adaptive trigger delay on image quality to correct for heart rate variability in 3D whole-heart coronary MR angiography (MRA). Materials and Methods Twelve healthy adults underwent 3D whole-heart coronary MRA with and without the use of an adaptive trigger delay. The moment of minimal coronary artery motion was visually determined on a high temporal resolution MRI. Throughout the scan performed without adaptive trigger delay, trigger delay was kept constant, whereas during the scan performed with adaptive trigger delay, trigger delay was continuously updated after each RR-interval using physiological modeling. Signal-to-noise, contrast-to-noise, vessel length, vessel sharpness, and subjective image quality were compared in a blinded manner. Results Vessel sharpness improved significantly for the middle segment of the right coronary artery (RCA) with the use of the adaptive trigger delay (52.3 ± 7.1% versus 48.9 ± 7.9%, P = 0.026). Subjective image quality was significantly better in the middle segments of the RCA and left anterior descending artery (LAD) when the scan was performed with adaptive trigger delay compared to constant trigger delay. Conclusion Our results demonstrate that the use of an adaptive trigger delay to correct for heart rate variability improves image quality mainly in the middle segments of the RCA and LAD. J. Magn. Reson. Imaging 2008;27:1046,1053. © 2008 Wiley-Liss, Inc. [source]

Direct monitoring of coronary artery motion with cardiac fat navigator echoes

MAGNETIC RESONANCE IN MEDICINE, Issue 2 2003
Thanh D. Nguyen
Abstract Navigator echoes (NAVs) provide an effective means of monitoring physiological motion in magnetic resonance imaging (MRI). Motion artifacts can be suppressed by adjusting the data acquisition accordingly. The standard pencil-beam NAV has been used to detect diaphragm motion; however, it does not monitor cardiac motion effectively. Here we report a navigator approach that directly measures coronary artery motion by exciting the surrounding epicardial fat and sampling the signal with a k -space trajectory sensitized to various motion parameters. The present preliminary human study demonstrates that superior-inferior (SI) respiratory motion of the coronary arteries detected by the cardiac fat NAV highly correlates with SI diaphragmatic motion detected by the pencil-beam NAV. In addition, the cardiac fat navigator gating is slightly more effective than the diaphragmatic navigator gating in suppressing motion artifacts in free-breathing 3D coronary MR angiography (MRA). Magn Reson Med 50:235,241, 2003. © 2003 Wiley-Liss, Inc. [source]

Hemodynamic analysis of intracranial aneurysms with moving parent arteries: Basilar tip aneurysms

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 10 2010
Daniel M. Sforza
Abstract The effects of parent artery motion on the hemodynamics of basilar tip saccular aneurysms and its potential effect on aneurysm rupture were studied. The aneurysm and parent artery motions in two patients were determined from cine loops of dynamic angiographies. The oscillatory motion amplitude was quantified by registering the frames. Patient-specific computational fluid dynamics (CFD) models of both aneurysms were constructed from 3D rotational angiography images. Two CFD calculations were performed for each patient, corresponding to static and moving models. The motion estimated from the dynamic images was used to move the surface grid points in the moving model. Visualizations from the simulations were compared for wall shear stress (WSS), velocity profiles, and streamlines. In both patients, a rigid oscillation of the aneurysm and basilar artery in the anterio-posterior direction was observed and measured. The distribution of WSS was nearly identical between the models of each patient, as well as major intra-aneurysmal flow structures, inflow jets, and regions of impingement. The motion observed in pulsating intracranial vasculature does not have a major impact on intra-aneurysmal hemodynamic variables. Parent artery motion is unlikely to be a risk factor for increased risk of aneurysmal rupture. Copyright © 2010 John Wiley & Sons, Ltd. [source]