Primary angiitis of the central nervous system: serial MRI of brain and spinal cord

MRI findings in primary angiitis of the central nervous system (PACNS) are highly variable, ranging from normal to diffusely abnormal. We describe bra in and spinal cord abnormalities in patients with PACNS and changes over ti me, to provide criteria which could be useful for differential diagnosis. W e reviewed six patients, with a final diagnosis of PACNS, who underwent ser ial contrast-enhanced brain and spinal MRI. Follow-up ranged from 12 to 60 months. Brain MRI showed multiple small abnormalities in all patients, givi ng high signal on T2-weighted images, focal or diffuse, mainly in deep and subcortical white matter; four patients had both supra- and infratentorial lesions. On the initial MRI, in five patients, almost 90 % of the abnormal foci showed contrast enhancement. Virchow-Robin perivascular spaces were en larged and simultaneously patients also had spinal cord abnormalities, in t he cervical and thoracic segments in two, and exclusively cervical segment in one. Two patients had brain biopsy-proven PACNS; in the remainder, the d iagnosis of PACNS was presumptive, considering similarities in clinical and MRI features and MRI follow-up. On MRI, after steroid and immunosuppressiv e therapy, a significant decrease in the number and size of the abnormaliti es, enhancing and nonenhancing and of enhancing perivascular spaces was obs erved. Simultaneous enhancement of brain and spinal cord lesions and of per ivascular spaces, at the onset of the disease, which resolves during follow -up, can therefore suggest PACNS.