Focal transient lesion in the splenium of the corpus callosum in three non-epileptic patients.
BACKGROUND
We analyzed the imaging features of transient focal lesions in the splenium of the corpus callosum (SCC) in non-epileptic patients receiving antiepileptic drugs (AEDs).


METHODS
We identified signal abnormalities in the SCC in three non-epileptic patients, all of them receiving AEDs. We examined two of these patients with multiplanar magnetic resonance (MR) imaging using 1.0-T equipment including fluid-attenuated inversion recovery (FLAIR), T2-weighted (TSE) and T1-weighted (SE) sequences before and after injection of contrast agent. The third patient was studied using 1.5-T equipment with the same sequences. Additionally, a T1 SE sequence with a magnetization transfer contrast pulse off resonance (T1 SE/MTC), diffusion-weighted imaging (EPI-DWI) and apparent diffusion coefficient (ADC) maps were obtained.


RESULTS
We observed an identical pattern of imaging abnormalities in all patients characterized by round lesions, hyperintense on FLAIR and hypointense on T1 SE images, located in the central portion of the SCC. One lesion showed homogeneous gadolinium enhancement and perilesional vasogenic edema. This particular lesion showed restricted diffusion confirmed on the ADC map. This pattern was considered consistent with focal demyelination. Follow-up MR examinations showed complete disappearance or a clear reduction in lesion size. All patients had been treated with AEDs, but they did not show any clinical signs of toxicity, interhemispheric symptoms, or abnormal neurological findings (including seizures).


CONCLUSIONS
We believe that our MR findings might be interpreted as transient lesions related to AED toxicity. They presumably resulted from focal demyelination in the central portion of the SCC.
da Rocha
Antônio José
AJ
Section of Radiology, Centro de Medicina Diagnóstica Fleury, Santa Casa de Misericórdia de São Paulo, São Paulo, Brazil. antonio.rocha@fleury.com.br
Reis
Fabiano
F
Gama
Hugo Pereira Pinto
HP
da Silva
Carlos Jorge
CJ
Braga
Flávio Túlio
FT
Maia
Antônio Carlos Martins
AC
Cendes
Fernando
F
D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects*; D001927:Brain Diseases / Q000139:chemically induced*; D003337:Corpus Callosum / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010672:Phenytoin / Q000009:adverse effects*; D020888:Vigabatrin / Q000009:adverse effects*
D000927:Anticonvulsants; D010672:Phenytoin; D020888:Vigabatrin