Role of magnetic resonance imaging in the diagnosis of primary central nervous system angiitis

The present study reported on the use of magnetic resonance imaging (MRI) in the diagnosis of primary angiitis of the central nervous system (PACNS). A total of 19 consecutive patients with a clinical diagnosis of PACNS confirmed by clinical follow-up were enrolled in the present study. All patients underwent unenhanced and enhanced MRI prior to and after steroids or steroids plus immunosuppressive therapy. At baseline, all patients showed lesions on MRI in the grey and white matter. Lesions presented as slightly hypointense on T1-weighted images (T1WI), slightly hyperintense on T2WI, hyperintense on fluid-attenuated inversion recovery, iso- or slightly hyperintense on diffusion-weighted images (DWI) and hyperintense on apparent diffusion coefficient (ADC) mapping. After contrast injection, the lesions showed patchy, cord-like or goral enhancement. Seven cases had unilateral lesions and the other 12 cases had bilateral lesions. On all sequences, indistinct margins characterised most of the lesions, and certain lesions were oedematous. Treatment with steroids or steroids plus immunosuppressive agents resulted in improvement or disappearance of symptoms, and seventeen patients had evidently improved according to MRI. In conclusion, PACNS has unique characteristics on MRI; DWI, ADC mapping and enhanced images are of great importance for the diagnosis and clinical management of early-stage PACNS.