CONTRIBUTION OF T-2 RELAXATION-TIME MAPPING IN THE EVALUATION OF CRYPTOGENIC TEMPORAL-LOBE EPILEPSY

In this study we compared the results of visual analysis of MR imaging with T-2 relaxation time mapping of the mesial structures in a group of 97 patients with cryptogenic temporal lobe epilepsy. All patients u nderwent a clinical neurological examination, neuropsychological inves tigation, prolonged video-EEG monitoring, SPECT imaging, MR imaging, a nd T-2 relaxation time mapping. T-2 relaxation times were estimated wi th a Carr-Purcell-Meiboom-Gill pulse sequence with 48 echoes (15 to 72 0 ms). The mean T-2 relaxation time value was 118.5 +/- 2 ms in the hi ppocampi and 120.3 +/- 1.9 ms in the amygdala of 21 healthy subjects u sed as controls. Ta relaxation mapping revealed mesial temporal sclero sis in 91.8% of the patients (often involving both the hippocampus and the amygdala) and evidenced bilateral involvement in 44.6% of the pat ients against 72.2 and 6.2%, respectively, for MR imaging. The ipsilat eral and contralateral hippocampal T-2 relaxation time values did sign ificantly correlate with seizure frequency and the contralateral hippo campal T-2 relaxation time value with the duration of epilepsy. In con clusion, this quantitative method is highly sensitive for the detectio n of mesial temporal sclerosis and permits a better evaluation of the apparently normal contralateral mesial structures. (C) 1998 Academic P ress.