In vivo wall shear stress measured by magnetic resonance velocity mapping in the normal human abdominal aorta.

OBJECTIVE: To apply a new non-invasive method for quantification of in vivo wall shear stress (WSS) by magnetic resonance (MR) FAcE velocity mapping and measure WSS in the human abdominal aorta.
DESIGN: Prospective, open study. MATERIAL: Six volunteers.
METHODS: MR FAcE velocity method was developed for measurements of mean, maximum, minimum WSS and oscillating shear index (OSI) values at the anterior and posterior walls of suprarenal and infrarenal abdominal aorta.
RESULTS: The mean, maximum and minimum WSS values were 0.63/0.28, 4.07/2.72 and -0.71/-1.00 N/m2, respectively, in the suprarenal/infrarenal aorta. The mean WSS was 0.35 N/m2 (p < 0.001) and the maximum WSS was 1.36 N/m2 (p < 0.0001) lower in the infrarenal aorta than in the suprarenal aorta. Mean, maximum minimum WSS and OSI values in the infrarenal position differed (p < 0.01) between the anterior and posterior walls.
CONCLUSION: 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.