HEMODYNAMICS IN THE ABDOMINAL-AORTA - A COMPARISON OF IN-VITRO AND IN-VIVO MEASUREMENTS

In vivo measurements of blood velocity profiles are difficult to obtai n and interpret, since the parameters that govern the normally highly complex flow situation may not be fully quantified or understood at th e time of measurement. In vitro flow models have been used often to be tter understand vascular hemodynamics. The assumptions made in the des ign of these models limit the applicability of the results. In this st udy, in vitro flow measurements made in a carefully designed model of the abdominal aorta were compared with in vivo measurements obtained w ith magnetic resonance imaging. In the suprarenal aorta, the velocity profiles were mostly forward and axisymmetric in both the in vitro and in vivo cases. In the infrarenal aorta, there was extensive flow reve rsal noted near the posterior wall in both cases. In the aortic bifurc ation, two peaks of flow reversal were noted near the lateral posterio r walls, and M-shaped velocity profiles were observed in late diastole . The in vitro and in vivo measurements exhibited good qualitative agr eement. The in vitro model was accurate in modeling the in vivo hemody namics of the abdominal aorta. The complex phenomena observed in vivo were explained on the basis of knowledge gained from the in vitro stud y.