LDV MEASUREMENTS IN LATERAL MODEL ANEURYSMS OF VARIOUS SIZES

Laser Doppler velocimetry (LDV) measurements are presented of three-di mensional flow fields in lateral model aneurysms arising from a straig ht parent vessel at a 90 degrees angle. The flow considered was pulsat ile and the aneurysm wall was rigid. The mean, peak, and minimal Reyno lds numbers based on the bulk average velocity and diameter of the par ent vessel were 550, 790, and 375, respectively. Comparisons among pre sent in vitro studies, previous in vitro studies, computational simula tions, and in vivo studies were made. It was found that the inflow ang le into the lateral aneurysm, the maximum wall shear stress acting on the distal lip of the lateral aneurysm, and the intra-aneurysmal vorti cal motion increased with decreasing aneurysm size. This fact together with the impingement bifurcation of the inflow at the aneurysm dome p rovide possible hemodynamic factors for the rupture of the lateral ane urysm at small critical size.