Radiologic investigation of abdominal aortic aneurysm disease: comparison of three modalities in staging and the detection of inflammatory change.

PURPOSE

The purpose of this study was to compare the ability of ultrasonography (US), contrast-enhanced computed tomography (CT), and magnetic resonance imaging (MRI) to display the anatomy of abdominal aortic aneurysms and to detect the presence of inflammatory change.

METHODS

We prospectively studied 79 patients with abdominal aortic aneurysms (64 noninflammatory aneurysms [NIAAs] and 15 inflammatory aneurysms [IAAs]) with US, CT, and MRI.

RESULTS

Ultrasonography failed to diagnose the level of the aneurysm neck in three IAAs and 18 NIAAs. It failed to differentiate NIAAs from IAAs and to visualize the origins of the renal arteries in all cases. With CT the level of the aneurysm neck was incorrectly stated as lying above the level of the renal arteries in two cases of IAA and four cases of NIAA, and the renal artery origins were seen in only 10 of 77 patients. Inflammatory change was diagnosed correctly in seven of 15 patients, whereas six NIAAs were falsely diagnosed as inflammatory. MRI successfully diagnosed neck level and inflammatory change in all cases. Of two failures to visualize the renal artery origins, only one was caused by radiologic factors. In addition, characteristic radiologic features were seen in MRI images of IAAs, and these will be described both in vivo and in vitro.

CONCLUSIONS

Our results suggest that MRI is superior to other methods in identifying the anatomy of aneurysms and the presence of inflammatory change.