Serial MRI and MRS studies with unusual findings in Rasmussen’s encephalitis

Abstract

Rasmussen's syndrome is characterized by intractable seizures and progressive neuropsychiatric deterioration secondary to unilateral cortical inflammation and tissue destruction. Diagnosis of Rasmussen's syndrome in the early phase depends mainly on the clinical features. Neuroimaging and histopathologic examinations may not be specific during this period. We report a case of Rasmussen's syndrome followed by serial MRI and magnetic resonance spectroscopy (MRS) studies over a 3- to 16-month period. A healthy 6-year-old boy presented with focal motor seizures. An MRI study demonstrated prominent enlargement and T2 hyperintensity of the left mesial temporal lobe and perisylvian region. This early finding evolved to volume loss and later progressive atrophy of the ipsilateral hemisphere when epilepsia partialis continua occurred. Being aware of those early MRI features in a patent with increasing frequency of focal motor seizures should suggest Rasmussen's syndrome. In addition, we found prominently increased myoinositol concentration in atrophic cortex which might reflect increased gliosis in the late period of the disease.

Diffusion MRI and spectroscopy in Rasmussen's encephalitis

“…Clinical features consist of severe or intractable epilepsy, hemiparesis, and progressive neurological and mental deterioration. Its etiology is unknown; however, a viral cause, including cytomegalovirus, Epstein-Barr virus, or slow virus infection, and an autoimmune cause related to glutamate receptor, has also been suggested [1,2,3,4,5,6,7,8]. With respect to the MRI findings in the current patients with Rasmussen's encephalitis, although conventional T2-weighted and FLAIR sequences revealed high-signal changes indicating presence of definite pathology in two of the patients (Figs.…”

“…As NAA is as a neuronal and axonal marker, a decrease of its peak indicated some destruction of the tissue with chronic infammation [9,10]. In the previously reported cases of Rasmussen's encephalitis decreased NAA peaks were the main spectroscopy finding in association with increased choline peaks [7,8]. Choline is a component of phosphoglyceride, and is the main component of cell membrane, reflecting changes in cell membrane turnover [9,10].…”

“…The condition has previously been studied by various imaging modalities including MRI and proton MR spectroscopy [1,2,3,4,5,6,7,8]. Recently, a report dealt with echo-planar diffusion MRI in three patients with Rasmussen's encephalitis [8].…”

Imaging Biomarkers of the Neuroimmune System among Substance Use Disorders: A Systematic Review

“…With MRS, the neurometabolite myo- inositol is thought to be a biomarker of the neuroimmune system [35]. Myo- inositol is a putative glial marker located in cultured astrocytes [36-39] and is associated with microglia [40]. Myo- inositol functions as a secondary messenger [41, 42], osmolyte [36, 43-47], and precursor of membrane phospholipids [42].…”

Biomarkers of Epileptogenesis: The Focus on Glia and Cognitive Dysfunctions

“…In particular, 1 H-MRS is an in vivo imaging technique which allows area-specific detection and quantification of myo-inositol (mIns), a sugar alcohol found predominantly in astrocytes [26], which represents a quantifiable indicator of reactive astrogliosis [33,34]. 1 H-MRS has been used to detect brain areas of reactive astrogliosis in patients with temporal lobe epilepsy, tuberous sclerosis and Rasmussen's encephalitis [35][36][37], therefore it may provide a sensitive measure of glia activation within the epileptic network.…”