Morphologic mural changes in the aorta revealed by CT in patients with nonspecific aortoarteritis (Takayasu's arteritis).

OBJECTIVE: Nonspecific aortoarteritis is a panarteritis of unknown cause that primarily involves vessel walls. The imaging morphology of changes caused by nonspecific aortoarteritis has been infrequently studied. SUBJECTS AND METHODS: We analyzed this morphology by axial CT in 24 patients (group 1) and compared these images with those of healthy subjects (n = 12, group 2) and subjects with atherosclerosis (n = 12, group 3), aortic aneurysm (n = 9, group 4), and aortic dissection (n = 5, group 5). Ten-millimeter contiguous sections were obtained before and after enhancement with contrast material.
RESULTS: Distinctive wall changes were seen in group 1 and included thickening in 20 patients, crescents in 19, indistinct outline in 10, and low-attenuation ring in eight. Calcification and thrombus were seen in 13 and seven patients, respectively. Angiograms showed skip areas of involvement. CT scans showed wall changes even in skipped areas that were normal at angiography. In group 2, the aortic wall was imperceptible or less than 1 mm thick and showed no abnormality. In group 3, calcification was seen in all patients and wall abnormality in none. In group 4, changes, including thrombus in all patients, calcification in nine, and low-attenuation ring in one patient, were seen within the aneurysm. In group 5, changes included calcification and the intimal flap in all patients and thrombus in three.
CONCLUSION: CT shows distinctive changes in the aortic wall in patients with non-specific aortoarteritis that are peculiar to this disease. Detecting these changes may improve our understanding of the disease pathogenesis. Our findings suggest that this disease involves a contiguous length of the aorta, producing wall and luminal diameter changes in some areas and only wall changes in the intervening segments.