Follow-up CT Evaluation of the Mural Changes in Active Takayasu Arteritis

OBJECTIVE: We wanted to evaluate the mural changes by CT on the follow-up examination of patients with active Takayasu arteritis. MATERIALS AND METHODS: The study included 18 patients, (4 males and 14 females), with active Takayasu arteritis. A total of 44 CT examinations were done during the follow-up period (mean: 55.6 months). At the time of the last follow-up CT, the disease, on the basis of the erythrocyte sedimentation rate (ESR), was found to be inactive in five patients and the disease was active and persistent in 13 patients. The thickness and CT attenuation of the aortic wall on the precontrast, arterial and venous phases were measured on the initial and the follow-up CT examinations. The ratio of the mural attenuation over that of the back muscle on the initial CT was compared with the ratio found on the follow-up CT. RESULTS: The initial CT findings included high density and calcifications of the aortic wall in the precontrast images and a thickened wall with enhancements in the arterial and the venous phases. A low-attenuation ring was demonstrated in the venous phase in 15 patients (83%). On the follow-up evaluation, the mean mural thickness decreased significantly from 4.1 mm to 2.4 mm. The mean mural attenuation ratio in the venous phase decreased significantly from 1.9 to 1.3 (p = 0.001). The low attenuation ring was identified in seven patients (39%) who had only with active, persistent Takayasu arteritis. CONCLUSION: The mural changes demonstrated by the follow-up CT evaluations for the patients with active Takayasu arteritis included a decrease of the mural thickness and enhancement, disappearance of the low-attenuation ring on the venous phase, and an increase of the mural attenuation and calcification on the precontrast phase.