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Protodiastole and vessel damage in atherosclerosis

Beraia M., Todua F., Khomeriki I.

Biocybernetics and Biomedical Engineering

2006

Vol. 26, no. 3

65-75

Hemodynamic forces are now known to be the localizing factors in atherogenesis, but conclusions as to the causes of the vessel wall damage are inconsistent. The purpose of the study was examination of the blood flow features in the aortic arch and establishment of the initial factors of atherogenesis. 15 men (age from 27 to 35 years) have been examined by magnetic resonance angiography on Siemens-Sonata-Cardio unit. Blood flow peak systolic velocity changes at the opposite walls of the aortic arch have been revealed. During protodiastole, the flow was found to form opposite directed streams, and a flow arrest with a flat flow profile was noted in discrete sites of the aorta. At these specified places, the peak systolic velocity was found to be low. Blood protodiastolic acceleration was 6 times higher than in the systole, and the shear stress was found to exceed the verge of the endothelial endurance. The circular blood flow at the aortic arch in protodiastole is characterized by a high acceleration, and the gradient pressure in the flat profile can damage the internal layers of the vessel.

Advances of blood vessel morphology analysis in 3D magnetic resonance images

Orkisz M., Hernandez-Hoyos M., Douek P., Magnin I.

Machine Graphics and Vision

2000

Vol. 9, No. 1/2

463-471

We deal with image processing applied to 3D analysis of vascular morphology in magnetic resonance angiography (MRA) images. It is, above all, a state-of- the-art survey. Both filtering and segmentation techniques are discussed. We briefly describe out most recent contribution: an anisotropic non-linear filter which improves visualization to small blood vessels. Enhancement of small vessels is obtained by combining a directional L-filter applied according to the locally estimated orientation of image content and a 2D laplacian orthogonal to this orientation.