Assessment of Pseudocoarctation of the Aorta with Saccular Aneurysms by Four-Dimensional Flow Magnetic Resonance Imaging and Histological Analysis

In this study, we present the case of a 21-year-old woman with pseudocoarctation of the aorta with saccular aneurysms that were evaluated by four-dimensional flow magnetic resonance imaging and histological analysis. We observed complete occupation of the aneurysm sacs by vortex flow and high peak wall shear stress in the proximal region of the kinked aorta. The aortic replacement was performed for the thoracic aortic aneurysms and the clinical course was uneventful. The aneurysms were histopathologically diagnosed as pseudoaneurysms based on the disappearance of all three layers and their replacement with collagen-rich connective tissues. These findings indicate that abnormal flow dynamics and the resulting abnormal shear stress in the aorta may play central roles in the formation and development of a saccular aneurysm.