MULTIMODALITY MRI IN MESIAL TEMPORAL SCLEROSIS - RELATIVE SENSITIVITYAND SPECIFICITY

Our objectives were to determine the relative sensitivity and specific ity of different MRI sequences and analysis techniques for the detecti on of mesial temporal sclerosis (MTS). Mesial temporal sclerosis is th e most common pathologic finding in patients undergoing temporal lobe epilepsy surgery. Magnetic resonance imaging is the most reliable preo perative imaging technique for the detection of MTS. We analyzed the a bnormalities in preoperative MRIs of 44 consecutive patients who had u ndergone temporal lobectomy and who had pathologic confirmation of MTS , Techniques included inversion recovery (IR); T1-weighted, volume-acq uired images; hippocampal T2 relaxometry (HT2); volumetric assessment; and visual analysis. Sensitivity was 86% with IR, 90% with T1-weighte d qualitative visual analysis, and 97% with quantitative volumetry. Pa thologic prolongation of HT2 (>2 SD of normal) was present in 79%. Ana lysis of variance showed statistically significant differences in sens itivity between HT2, volumetric measurements (p < 0.01), and qualitati ve visual atrophy (p < 0.05). Concordance between all MRI modalities w as 68%. Inversion recovery and qualitative analysis lateralized the si de of surgery in 93%. The combination of IR and T1-weighted images cor rectly identify MTS in most patients. Hippocampal volumetry provided l ocalization in an additional small number of patients.