Multimodal Imaging in the Diagnosis of Large Vessel Vasculitis: A Pictorial Review

Vasculitis is a pathologic process characterized by vessel inflammation with leukocyte infiltration into the vessel wall. The large vessel vasculitides (LVV), such as giant cell arteritis (GCA) and Takayasu arteritis (TA) involve similar histologic abnormalities but differ in the age of onset and vessels that are preferentially targeted [1]. Both present with systemic symptoms, such as fever and raised inflammatory markers. GCA occurs in patients exclusively older than 50 years and classically involves the extracranial aortic branches of internal and external carotid arteries, in particular, the temporal arteries, although any organ system can be involved. Involvement of the subclavian, axillary, and proximal brachial arteries leads to the aortic arch syndrome of claudication of the arms and absent or asymmetric pulses [2]. TA is mostly seen in women under the age of 40 years and has the greatest prevalence in Asians [3]. It primarily involves the aorta and its branches, in particular, the subclavian arteries [4]. The abdominal aorta and pulmonary vessels are involved in up to half of the cases. An angiographic classification (types I-V) exists based on the site of involvement of the aorta [4]. A recent patient series that involved 25 patients with TA found type V to be the most common type, which involves the entire aorta, including the