Use of imaging techniques in large vessel vasculitis and related conditions.

Giant cell arteritis (GCA) and Takayasu's arteritis (TA) are large vessel vasculitis (LVV) primarily affecting the aorta and its major branches, mainly differentiated by the onset age (>50 years GCA and <40 years TA). In addition, temporal artery involvement and polymyalgia rheumatica are typical features of GCA, but not TA. Imaging techniques are required to secure the diagnosis of large-vessel vasculitides, and to monitor the disease course. Both morphological and metabolic imaging are involved. Morphological imaging is represented mainly by computerized tomography (CT), CT angiography, magnetic resonance (MR), MR angiography, color-Doppler sonography (CDS) and high-resolution CDS. Metabolic aspects of inflammatory process in LVV can be well studied by positron emission tomography/computed tomography with [18F]deoxyglucose ([18F]FDG PET/CT). It has an important increasing role in diagnosis, extent assessment and disease activity and therapy response evaluation. In the near future the concomitant development of increasingly powerful PET/CT scanners, of new radiopharmaceuticals more specific for inflammation, and of new PET/MRI hybrid scanners probably will lead to a further new step forward in the diagnosis and clinical management of LVV.