Analysis of Blood Flow Patterns in Aortic Aneurysm by Cine Magnetic Resonance Imaging-

Cine magnetic resonance imaging (MRI) (0.5-T) using rephased gradient echo technique was performed in 5 normal volunteers and 14 patients with aortic aneurysm to study the patterns of blood flow in aortic aneurysm. In the transaxial section, blood flow in normal aorta appeared as homogeneous and high intensity during systole. Blood flow in aneurysm appeared as inhomogeneous flow enhancement with flow void. In the sagittal scan, the homogeneous flow enhancement in normal aorta was also observed during systole, and its apex of flow enhancement was "taper." The blood flow patterns in aneurysm were classified as "irregular," "zonal," "eddy," and "obscure," depending on the contrast of flow enhancement and flow void. Their apexes were "taper" or "round." When the size of aneurysm became larger, the flow pattern in aneurysm tended to become "eddy" or "obscure" and the flow enhancement became "round." Though the exact mechanism of abnormal flow patterns in aneurysm remains to be determined, cine MRI gives helpful information in assessing blood flow dynamics in aneurysm.