The potentials and pitfalls of magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) in the diagnosis of large vessel vasculitis are summarized in this review article. With the ability to visualize the lumen and vessel walls of large and medium sized arteries, MRI and MRA have great potential to play a unique role in the diagnosis of large vessel vasculitis. This is underlined by the fact that mural inflammatory changes typically involve uptake of contrast agent that can be visualized with MRI. The cranial, intracranial and extracranial involvement pattern can be studied in a combined approach including an MRI examination of the superficial cranial arteries and an MRA examination of the thoracic aorta with its major supra-aortic branches. Typical MRI sequence parameters are given including monophasic MRA and time-resolved MRA protocols at 3 T. The MRI and MRA techniques have the potential to determine the most suitable (inflamed) segment for temporal artery biopsy and to monitor treatment. Initial results of multicenter studies for the diagnostic accuracy of these relatively new methods are expected soon. The MRA technique is recognized as an interesting alternative to invasive catheter angiography for the evaluation of central nervous system (CNS) vasculitis.
