Differences in the time course of splenial and white matter lesions in clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS)

Splenial and White Matter Lesions Showing Transiently-reduced Diffusion in Mild Encephalopathy Monitored with MR Spectroscopy and Imaging

“…Reversible lesions with transiently reduced diffusion have also been found extended laterally from the splenium into the subcortical white matter and in anterior extension in- volving the entire corpus callosum; such lesions are designated MERS type 2. 7 The lesion in our case was similar to MERS type 2 with regard to both the clinically benign course and initial MR imaging findings and the DWI time course during followup. A previous report described an atypical case of MERS that showed a splenial lesion with transiently reduced diffusion in clinically mild encephalitis but persistent abnormal signal in an SCC lesion in T 2 WI and FLAIR images.…”

“…Follow-up MR imaging and spectroscopy in our case suggested the occurrence of some degenerative changes after intramyelinic edema in the residual abnormal signal in white matter. Takanashi and associates 7 reported the resolution of MERS type 2-exhibiting lesions in the white matter and entire corpus callosum through an isolated lesion of the splenium of the corpus callosum (type 1). They suggested that MERS types 1 and 2 have the same pathology.…”

Transient Hemiparesis and Hemianesthesia in an Atypical Case of Adult-onset Clinically Mild Encephalitis/ Encephalopathy with a Reversible Splenial Lesion Associated with Adenovirus Infection

“…The first hypothesis, which we support, is that the culprit lesion was located within the deep white matter above the midbrain, although it was not detectable on MR imaging. This possibility concurs with the neuroanatomical localization of the lesions and the fact that MERS can involve regions of the deep white matter besides the splenium of the corpus callosum (10). The second hypothesis is related to the splenium of the corpus callosum lesion itself.…”

Reversible splenial lesion syndrome in children: Retrospective study and summary of case series

“…It was further proposed to be classified into MERS type 1, with an isolated SCC lesion, and MERS type 2, with an extensive white matter and/or entire callosal lesions [4]. Other potential causes of reversible splenial lesions, such as seizures, antiepileptic drug withdrawal, metabolic disturbances, and other miscellaneous conditions, were also reported [3].…”