Automated MRI Volumetric Analysis in Patients with Rasmussen Syndrome

BACKGROUND AND PURPOSE: Rasmussen syndrome, also known as Rasmussen encephalitis, is typically associated with volume loss of the affected hemisphere of the brain. Our aim was to apply automated quantitative volumetric MR imaging analyses to patients diagnosed with Rasmussen encephalitis, to determine the predictive value of lobar volumetric measures and to assess regional atrophy differences as well as monitor disease progression by using these measures. MATERIALS AND METHODS: Nineteen patients (42 scans) with diagnosed Rasmussen encephalitis were studied. We used 2 control groups: one with 42 age- and sex-matched healthy subjects and the other with 42 epileptic patients without Rasmussen encephalitis with the same disease duration as patients with Rasmussen encephalitis. Volumetric analysis was performed on T1-weighted images by using BrainSuite. Ratios of volumes from the affected hemisphere divided by those from the unaffected hemisphere were used as input to a logistic regression classifier, which was trained to discriminate patients from controls. Using the classifier, we compared the predictive accuracy of all the volumetric measures. These ratios were used to further assess regional atrophy differences and correlate with epilepsy duration. RESULTS: Interhemispheric and frontal lobe ratios had the best prediction accuracy for separating patients with Rasmussen encephalitis from healthy controls and patient controls without Rasmussen encephalitis. The insula showed significantly more atrophy compared with all the other cortical regions. Patients with longitudinal scans showed progressive volume loss in the affected hemisphere. Atrophy of the frontal lobe and insula correlated significantly with epilepsy duration. CONCLUSIONS: Automated quantitative volumetric analysis provides accurate separation of patients with Rasmussen encephalitis from healthy controls and epileptic patients without Rasmussen encephalitis, and thus may assist the diagnosis of Rasmussen encephalitis. Volumetric analysis could also be included as part of follow-up for patients with Rasmussen encephalitis to assess disease progression.

[1]  F. Jensen,et al.  Rasmussen's encephalitis: clinical features, pathobiology, and treatment advances , 2014, The Lancet Neurology.

[2]  Richard M. Leahy,et al.  A Method for Automated Cortical Surface Registration and Labeling , 2012, WBIR.

[3]  C. Elger,et al.  Automated 3D MRI volumetry reveals regional atrophy differences in Rasmussen encephalitis , 2012, Epilepsia.

[4]  Richard M. Leahy,et al.  Comparison of landmark-based and automatic methods for cortical surface registration , 2010, NeuroImage.

[5]  C. Filippi,et al.  Diffusion tensor imaging and tractography of Rasmussen encephalitis , 2009, Pediatric Radiology.

[6]  C. Elger,et al.  Astrocytes are a specific immunological target in Rasmussen's encephalitis , 2007, Annals of neurology.

[7]  B. Thomas,et al.  Putaminal involvement in Rasmussen encephalitis , 2006, Pediatric Radiology.

[8]  C. Elger,et al.  MRI brain volumetry in Rasmussen encephalitis: The fate of affected and “unaffected” hemispheres , 2005, Neurology.

[9]  E. Vining,et al.  The Pathology of Rasmussen Syndrome: Stages of Cortical Involvement and Neuropathological Studies in 45 Hemispherectomies , 2004, Epilepsia.

[10]  L. Tassi,et al.  Diagnostic imaging in 13 cases of Rasmussen's encephalitis: can early MRI suggest the diagnosis? , 2003, Neuroradiology.

[11]  F. Andermann,et al.  Bilateral Rasmussen Encephalitis: Postmortem Documentation in a Five‐year‐old , 2003, Epilepsia.

[12]  C. Elger,et al.  The natural history of Rasmussen's encephalitis. , 2002, Brain : a journal of neurology.

[13]  Richard M. Leahy,et al.  BrainSuite: An Automated Cortical Surface Identification Tool , 2000, MICCAI.

[14]  C. Polkey,et al.  Rasmussen’s Encephalitis: Neuroimaging Findings in 21 Patients with a Closer Look at the Basal Ganglia , 1998, Pediatric Neurosurgery.

[15]  Alice S. Whittemore,et al.  Logistic regression of family data from case-control studies , 1995 .

[16]  Y. Benjamini,et al.  Controlling the false discovery rate: a practical and powerful approach to multiple testing , 1995 .

[17]  O. Dulac,et al.  Reappraisal of Rasmussen's syndrome with special emphasis on treatment with high doses of steroids. , 1994, Journal of neurology, neurosurgery, and psychiatry.

[18]  T. Rasmussen,et al.  The syndrome of chronic encephalitis and epilepsy. A study based on the MNI series of 48 cases. , 1992, Advances in neurology.