Background In young patients, vasculitic stenoses of cerebral blood vessels are an important cause of cerebral ischaemia. Diagnosis may prove very difficult. Summary of review The diagnostic process is usually initiated by the detection of brain lesions consistent with cerebral vasculitis. Multiple infarcts of various ages in more than one vascular territory are thought to be suggestive of a vascular inflammatory disease. The next step in the imaging of patients with suspected vasculitis is the search for an underlying vascular stenosis. Today, magnetic resonance angiography is the principal modality for the investigation of patients thought to have intracranial stenoses. At 1·5 T, only large brain arteries can be imaged with a high diagnostic accuracy. Intraarterial DSA remains an indispensable tool for the investigation of medium and small brain artery stenoses. Conclusions However, contrast-enhanced magnetic resonance imaging may be able to demonstrate wall thickening and contrast uptake in large cerebral arteries, obviating biopsy in patients with basal vasculitis.