Delayed enhancement on computed tomography in abdominal aortic aneurysm wall.

The purpose of this study was to evaluate delayed enhancement (DE) of the aortic wall of atherosclerotic aneurysms using computed tomography and to evaluate the relationships between DE and wall thickness of abdominal aortic aneurysm (AAA), diameter of AAA, serum levels of C-reactive protein (CRP) which indicate inflammation status, and pathological findings. Computed tomographic images of atherosclerotic AAA in 110 patients were studied between July 2001 and March 2003. Computed tomography (CT) scanning included unenhanced, enhanced early, and enhanced delayed phases. Pathological findings were obtained from 19 of the 110 patients. We determined DE of the AAA wall and assessed the association between DE and AAA wall thickness, AAA diameter, serum levels of CRP, and pathological findings. Delayed enhancement on CT was demonstrated in 66 of 110 patients with atherosclerotic AAA (60.0%). Patients with DE demonstrated significantly larger AAA diameter (4.8 +/- 0.9 versus 3.9 +/- 0.6 cm, P < 0.0001) and significantly higher levels of CRP (5.0 +/- 6.0 versus 2.3 +/- 2.9 mg/l, P = 0.033) than those patients without DE. Patients with DE also had significantly thicker and more severe atheroma and a tendency toward more prominent inflammation and vascularity in pathologic findings. There was no significant difference in wall thickness between AAA with and without DE (1.44 +/- 0.7 versus 1.24 +/- 0.22 mm, P = 0.352). Delayed enhancement on CT demonstrated in over half of atherosclerotic AAA may be associated with chronic inflammation by atherosclerosis.