Pediatr Radiol (2006) 36: 816–822 DOI 10.1007/s00247-006-0176-4 ORIGINAL ARTICLE Bhagavatheeswaran Rajesh . Chandrasekharan Kesavadas . Radhakrishnan Ashalatha . Bejoy Thomas Putaminal involvement in Rasmussen encephalitis Received: 18 December 2005 / Revised: 4 March 2006 / Accepted: 13 March 2006 / Published online: 19 May 2006 # Springer-Verlag 2006 Abstract Background: Rasmussen encephalitis (RE) is a rare devastating disease of childhood causing progressive neurological deficits and intractable seizures, typically affecting one hemisphere. Characteristic MRI features include progressive unihemispheric focal cortical atrophy and grey- or white-matter high-signal changes and basal ganglion involvement, particularly of the caudate nucleus. Objective: To analyse the pattern of involvement of different brain structures in a series of patients with RE and to attempt clinical correlation. Materials and methods : We reviewed the medical records and neuro- imaging data of 12 patients diagnosed with RE satisfying the European Consensus Statement diagnostic criteria. Results: The disease manifested as seizures in all patients and was refractory; epilepsia partialis continua was a notable feature (nine patients). Hemi- paresis of varying grades was noted in all but one patient; none had extrapyramidal signs. Neuroimaging showed cortical involvement in the insular/periinsular regions in 11 patients. Caudate atrophy was noted in ten patients. Putaminal atrophy was seen in nine patients, six of whom had additional hyperintense signal changes. Conclusions: Our study highlights frequent putaminal atrophy and signal changes in RE, which suggests a more extensive basal ganglion involvement than em- phasized previously. Recognition of putaminal changes may be a useful additional tool in the radiological diagnosis of RE. Keywords Rasmussen encephalitis . Basal ganglia . Putamen . MRI . Epilepsy . Children Introduction Rasmussen encephalitis (RE) is a rare but devastating unihemispheric brain disorder usually affecting children and characterized by intractable seizures and progressive neurological deficits [1–4]. It progresses variably through a prodromal phase, acute phase and a residual burnt-out phase [5]. The aetiopathogenesis is not fully understood, although immune-mediated mechanisms are thought to be predominantly responsible [6]. In typical cases, clinical and MRI features are sufficient to diagnose RE and histopath- ological confirmation is not necessary [7]. Characteristic radiological features include unilateral enlargement of inner and outer CSF compartments [8], caudate atrophy [9] and progressive unihemispheric changes on serial imaging [10]. Imaging changes have been noted predominantly in the perisylvian region (insulotemporal) and caudate nucle- us. Basal ganglia (BG) changes involving the caudate have been well described, but putaminal involvement has not been adequately emphasized in these reports or in the recently proposed European Consensus Statement [7]. We observed frequent putaminal involvement in our series of patients with RE, which suggests that BG are extensively affected in RE. We highlight the putaminal involvement in RE which may be useful not only in furthering our understanding of the diffuse nature of this rare disorder, but also in the diagnosis of atypical presentations. Patients and methods Patient selection This study was conducted in a leading tertiary referral centre for all neurological disorders, but especially offering advanced care for epileptic disorders. We reviewed the medical records and neuroimaging data of those patients B. Rajesh . R. Ashalatha Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India C. Kesavadas (*) . B. Thomas Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695011, Kerala, India e-mail: chandkesav@yahoo.com Tel.: +91-471-2524431 Fax: +91-471-2446433