Melanie B. Peachell, MD; Nestor L. Muller, MD, PhD

Disclosures

Semin Respir Crit Care Med. 2004;25(5) 

In This Article

Takayasu's Arteritis

Takayasu's arteritis is an uncommon arteritis that affects the aorta and its proximal branches and, less commonly, the pulmonary arteries. Approximately 90% of cases occur in women and the majority of cases occur in Southeast Asia.[15,16]

The chest radiograph is frequently normal or shows nonspecific findings, including a scalloped contour of the descending thoracic aorta, ectasia of the arch, dilatation of the ascending aorta, and aortic calcification in a young patient.[17] CT is usually abnormal and, in the appropriate clinical setting, often allows confident diagnosis.

The findings on CT are best evaluated by performing CT before and after intravenous administration of contrast. CT without intravenous contrast typically demonstrates thickening and high attenuation of the involved vessel wall, usually the thoracic aorta or brachiocephalic artery, and, frequently, mural calcification.[18] The thickened wall shows enhancement following intravenous administration of contrast[18] (Fig. 4). Enhancement of the vessel wall following intravenous administration of contrast and the presence of an inner hypoattenuating rim are typically seen in patients with active disease.[18] Patients with longstanding but inactive disease tend to show high attenuation and calcification of the arterial walls on the precontrast images and lack of mural enhancement on the postcontrast images.[18] Involvement of the arterial wall can result in focal areas of stenosis or aneurysm formation. The most frequent site of stenosis is in the descending aorta whereas aneurysms are more commonly seen in the ascending aorta.[19]

Takayasu's arteritis. Computed tomographic image obtained following intravenous administration of contrast demonstrates thickening and enhancement of the wall of the aorta at the level of the aortic arch (arrows). The patient was a 32-year-old woman.

The pulmonary arteries are involved in 50 to 86% of patients and on CT demonstrate increased wall thickness and mural enhancement.[16,18] The vast majority of patients with pulmonary arterial involvement have concomitant involvement of the aorta or its branches.[18] Pulmonary parenchymal abnormalities have been described. In a recent retrospective study, 10 of 20 patients with Takayasu's were found to have areas of decreased pulmonary parenchymal attenuation and vascularity on HCRT (high resolution computed tomography).[20] The low attenuation areas were consistent with localized hypoperfusion, presumably secondary to pulmonary arteritis.

In the majority of patients the diagnosis of Takayasu's arteritis is made based on the clinical and CT findings. Magnetic resonance imaging (MRI) can also be useful. MRI can demonstrate the presence of wall thickening of the involved vessels, stenosis, and aneurysm formation.[19,21] MRI may be particularly helpful in demonstrating vascular anatomy in patients being evaluated in centers where spiral CT is not available. One case has been reported where positron emission tomography (PET) with fluorodeoxyglucose (FDG-PET) was useful in the early diagnosis of Takayasu's.[22] Increased uptake of FDG in Takayasu'sreflects the presence of marked inflammation of the vessel wall in the early stages of Takayasu's arteritis.[22]

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