A longitudinal MRI study in children with Rasmussen syndrome.

The aim of this study was to identify the presence of any neuroimaging patterns of Rasmussen syndrome using magnetic resonance imaging (MRI). This was a prospective study evaluating brain MRIs in seven children with neuropathologically proven Rasmussen syndrome. All patients were unresponsive to conventional antiepileptics; five patients subsequently underwent functional hemispherectomy, and two patients underwent cortical resection. Three to eight (mean = 4.7) MRIs per patient were performed, and neuropathologic examination of the brain was available. Serial MRIs were obtained between 12 months before and 9 months after the onset of epilepsia partialis continua. The most common region of initial MRI signal change was the frontocentral region (six patients). Three patterns of neuroimaging abnormalities were observed as follows: (1) normal MRI followed by increased signal intensity with progressive cortical atrophy over time, (2) initial increased focal signal intensity followed by decrease in spatial extent and degree of signal intensity; (3) initially increased signal intensity without further changes on follow-up scans. This observation suggests three possible distinct patterns of MRI changes in patients with Rasmussen syndrome and that the differences in these neuroimaging patterns may reflect inherent differences in the pathogenesis of Rasmussen syndrome.