Diagnostic Approaches for Large Vessel Vasculitides.

The large vessel vasculitides comprise giant cell arteritis (GCA), Takayasu arteritis (TAK), and chronic periaortitis. The diagnostic approach to these conditions involves the correct use and interpretation of clinical criteria, imaging techniques, and, in case of GCA, temporal artery biopsy. Ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) reveal a homogeneous, concentric, thickening of the arterial wall. MRI and CT may also reveal aneurysms and stenoses. 18F-Fluorodeoxyglucose (FDG)-PET shows increased FDG uptake of inflamed artery walls delineating increased metabolic activity. Ultrasound, FDG-PET, and MRI are the recommended imaging techniques in GCA and TAK. In patients with a high suspicion of GCA who present with visual disturbances, initiation of high-dose intravenous corticosteroids should not be delayed by imaging. Extracranial large vessel vasculitis may be confirmed by all three modalities, particularly by FDG-PET in case of atypical clinical pictures. In this article, we review the role of the GCA and TAK ACR classification criteria, temporal artery biopsy, conventional angiography, ultrasound, MRI, magnetic resonance angiography (MRA), CT angiography (CTA), and FDG-PET in the diagnostic approach of large vessel vasculitis.