Recent advances in diagnostic strategies for giant cell arteritis.

Giant cell arteritis (GCA) is a systemic vasculitis that affects the aorta and its major branches. Involvement of the ciliary artery can result in ischemic optic neuropathy and subsequent blindness, which is typically irreversible. If GCA is suspected, treatment with glucocorticoids should be initiated promptly to prevent further vision loss. However, given the need for prolonged therapy with glucocorticoids and the morbidity associated with their use, diagnosis should be confirmed. Clinical features and laboratory findings are neither sensitive nor specific for GCA. The mainstay of diagnosis remains histopathologic examination of a section of the superficial temporal artery. Several imaging studies have been used to evaluate the temporal artery but, at present, their utility as alternatives to a temporal artery biopsy is limited. Recent advances in imaging modalities have allowed detailed noninvasive imaging of the large arteries and are a useful adjunct for the diagnosis of GCA, particularly in patients with primarily large-vessel involvement in whom temporal artery biopsy is often negative.