Bilateral mesial temporal sclerosis: MRI with high-resolution fast spin-echo and fluid-attenuated inversion-recovery sequences

We report a retrospective analysis of MRI in 206 patients with intractable seizures and describe the findings in bilateral mesial temporal sclerosis ( MTS) on fast spin-echo (FSE) and fast fluid-attenuated inversion-recovery ( fFLAIR) sequences. Criteria for MTS were atrophy, signal change and loss of the digitations of the head of the hippocampus. In patients with bilateral MRI signs of MTS, correlation with clinical electro, volumetric MRT data a nd neuropsychological tests, when available, was performed. Bilateral MTS w as observed in seven patients. Bilateral loss of the digitations and signal change on fFLAIR was seen in all seven. In three, bilateral atrophy was ob vious. In two patients, mild bilateral atrophy was observed and in two othe rs, the hippocampi were: asymmetrical, with obvious atrophy on only one sid e. Volumetric data confirmed bilateral symmetrical atrophy in five patients , and volumes were at the lowest of the normal range in the other two. The EEG showed temporal abnormalities in all patients, unilateral in five and b ilateral in two. All patients had memory impairment and neuropsychological data confirmed visual and verbal memory deficits; two patients failed the W ada test on both sides. High-resolution T2-weighted FSE and fFLAIR sequence s allow diagnosis of bilateral MTS, which has important therapeutic and pro gnostic implications.