Takayasu arteritis: MR manifestations and diagnosis of acute and chronic phase.

Diagnosis of Takayasu arteritis is difficult because the clinical features are similar to those of other diseases. In the late occlusive or pulseless phase Takayasu arteritis, angiography usually demonstrates luminal changes such as such as stenosis, occlusion, or aneurysmal dilatation of the aorta and pulmonary artery and of their branches. However, absence of such luminal changes does not exclude the possibility of early or systemic phase Takayasu arteritis. Cross-sectional scanning such as CT scan and MRI plays an important role in demonstrating arterial wall changes in the early diagnosis of Takayasu arteritis. Improvement in the clinical findings and subsidence of the active inflammatory process can be expected with early steroid treatment. The common and uncommon MR appearances of the late occlusive phase and the recently described radiographic features of the early systemic phase are illustrated.