Diagnostic imaging in 13 cases of Rasmussen's encephalitis: can early MRI suggest the diagnosis?

Abstract

Rasmussen's encephalitis (RE) is a rare, progressive, chronic encephalitis characterised by drug-resistant epilepsy, progressive hemiparesis and mental impairment. It typically involves only one cerebral hemisphere, which becomes atrophic. We present neuroradiological findings in 13 children with RE. MRI was performed in all patients, fluorodeoxyglucose positron-emission tomography (PET) in three, Tc-99m hexamethylpropylenamine oxime single-photon emission computed tomography (SPECT) in two and proton MR spectroscopy ((1)HMRS) in two. MRI showed progression of the hemisphere atrophy, always prevalent in the region primarily involved (13 patients), spread of the abnormal signal in white matter (11) and cortex (10) and progression of atrophy of the head of the caudate nucleus (nine). Associated secondary changes were: atrophy of the contralateral cerebellar hemisphere (in four patients), the ipsilateral hippocampus (in five) and the brain stem (in five). The earliest CT and MRI abnormalities, seen between 1 day and 4 months after the first seizure (in 12 patients examined, nine of whom had MRI) in one cerebral hemisphere included: high signal on T2-weighted images in the cortex (seven patients) and white matter (nine), cortical atrophy usually involving the frontoinsular region, with mild or severe enlargement of the lateral ventricle (eight) and moderate atrophy of the head of the caudate nucleus (seven). Cortical swelling in the early stage of the disease was recognisable only in two patients. PET revealed hypometabolism, SPECT decreased perfusion, and (1)HMRS reduction of N-acetylaspartate in the affected hemisphere. PET and SPECT were usually performed in the late stages and did not provide specific findings. MRI thus demonstrates the progression of RE and may suggest the diagnosis in the early stages, often before the appearance of neurological deficits. Early diagnosis of RE may be crucial for selecting patients for aggressive medical therapy or major surgical interventions such as hemispherectomy.

Rasmussen's encephalitis in an Indian child

“…MRI has been shown to demonstrate the progression of Rasmussen's encephalitis and may suggest the diagnosis in the early stages, often before the appearance of neurological deficits. 6 Apart from atrophy of the head of the caudate nucleus; MRI may also show associated secondary changes such as atrophy of the contralateral cerebellar hemisphere, the ipsilateral hippocampus, and the brainstem. 6 There are four recognized stages of Rasmussen's encephalitis based on T2 weighted MRI criteria.…”

Rasmussen's Encephalitis - Chronic Focal Encephalitis (CFE) - A Rare Entity

“…21,22 Usually, within months of onset of the acute stage, most patients show unilateral enlargement of the ventricular system. A T2/FLAIR hyperintense signal is often present in cortical or subcortical regions, or both, the distribution is heterogeneous, and temporal fluctuation might be related to seizure frequency in patients without epilepsiapartialis continua.…”

Status Epilepticus in a Patient With Rasmussen’s Encephalitis

“…У некоторых пациентов временно выяв-лялся фокальный корковый отек при ранних сканированиях. Впоследствии наблюдалось распространение изменения сигнала и атрофии в пределах пострадавших полушарий [12,20].…”