The role of 18F-FDG positron emission tomography for the diagnosis of vasculitides.

Large-vessel vasculitis is the most common form of primary vasculitis comprising cranial and large-vessel giant cell arteritis, Takayasu's arteritis and idiopathic aortitis. Prompt diagnosis and treatment of large-vessel vasculitis are important to prevent potentially serious emergencies such as visual loss, vascular stenosis and aneurysm formation. Temporal artery biopsy has long been the standard for diagnosing GCA - an invasive technique that lacks sensitivity compared to a clinical diagnosis that relies on a combination of clinical symptoms, elevated serum inflammatory markers and imaging findings. Conventional angiography focussing on the detection of arterial stenoses and occlusion does not assess vessel wall changes. Therefore, angiography is being increasingly replaced by newer imaging modalities such as magnetic resonance imaging and 18F-FDG positron emission tomography-computed tomography. However, imaging modalities also including ultrasound are not uniformly used for diagnosis and monitoring of large-vessel vasculitis in clinical practice. Very recently recommendations for imaging have been developed by the European League Against Rheumatism and the Society of Nuclear Medicine and Molecular Imaging in cooperation with the European Association of Nuclear Medicine and an interest group endorsed by the American Society of Nuclear Cardiology. These and a small literature search using PubMed are the basis for this review.