Vessel involvement in giant cell arteritis: an imaging approach.

Vasculitis is classified based on the size of the involved vessels. The two major forms are small vessel vasculitis and large vessel vasculitis (LVV). Main forms of LVV are Takayasu arteritis, giant cell arteritis (GCA), isolated aortitis and chronic periaortitis. This manuscript will focus on GCA, named after the presence of giant cells in the artery vessel wall. A positive biopsy of the temporal artery is the gold standard for making a diagnosis of GCA. In the past 10 years the introduction of new imaging techniques in GCA patients has revealed a variable prevalence of extra cranial involvement, challenging the temporal artery biopsy as gold standard. Also, imaging has become important not only for diagnosing GCA but also for assessment of vascular damage in GCA and for the evaluation of treatment.