The hypothesis of a diastolic vortex formation in the human left ventricle was confirmed, and its close temporal relation to the motion of the anterior mitral leaflet was demonstrated.

Purpose:To investigate wall shear rates in vivo in the common carotid, brachial, and superficial femoral arteries using very high resolution magnetic resonance imaging (MRI) phase contrast measurements. Materials and Methods:Mean, maximum, and minimum wall shear rate and an oscillatory shear index were measured for 20 volunteers, aged 23.3 Ϯ 1.9 years, in the three arteries, using phase contrast imaging with 0.0625 mm 2 resolution and three-dimensional paraboloid fitting. Results:The superficial femoral artery had the lowest mean (130.3 Ϯ 13.1 second Ϫ1 ), maximum (735.8 Ϯ 32.4 second Ϫ1 ), and minimum (-224.5 Ϯ 17.0 second Ϫ1 ) wall shear rate, as well as the highest oscillatory shear index (0.21 Ϯ 0.02). All values were significantly different (P Ͻ 0.05) from both the brachial artery and the common carotid artery values. The highest mean (333.3 Ϯ 13.6 second Ϫ1 ) and minimum (117.9 Ϯ 24.5 second Ϫ1 ) wall shear rates and the lowest oscillatory shear index (0 Ϯ 0) were found in the common carotid artery. Conclusion:It is possible to measure wall shear rate in vivo in different arteries using MRI with very high resolution. The findings exhibit the in vivo environment of wall shear rates and suggest a nonuniform distribution of wall shear rates throughout the arterial system.

WSS can be determined in vivo by MR FAcE velocity technique. Since the lowest WSS values were measured in the infrarenal, posterior blood-to-wall interface, the theory of more pronounced atherosclerosis development in low and oscillating WSS domains was not contradicted by the results of the present study.

We describe a new noninvasive method for highly accurate estimation of blood flow, cross-sectional lumen vessel area and wall shear stress. In vitro results and statistical analysis demonstrate the feasibility of the method, and the first in vivo results are comparable to published data.