Magnetization Transfer Imaging for Detection of Mesial Temporal Sclerosis in Temporal Lobe Seizure

Seo, Jeong Jin; Kang, Heoung Keun; Maravilla, Kenneth R

Abstract

We evaluated the usefulness of magnetization transfer imaging for detection of mesial temporal sclerosis with temporal lobe seizure. Eighteen patients underwent MR imaging and histologically confirmed by operation were evaluated retrospectively. Twenty-seven normal control volunteers underwent MR imaging. Pixel-by-pixel MTR maps were reconstructed and quantitative MTR values were obtained. We calculated normalize the MTR values by dividing the MTR value of the hippocampus by the MTR value of adjacent temporal lobe white matter on each side. Normalized MTR values for the control population ranged between 0.63 and 0.79, resulted in approximately 40% suppression of signal from normal white matter. Normalized MTR values for the control population showed narrow range of distribution. Fifteen patients in this series with good quality MT images had histologically proven mesial temporal sclerosis. The lowest normal MTR value was 0.41. In comparison, the abnormal hippocampi with mesial temporal sclerosis tended to show lower normalized MT values. Additionally, the patients with more severe changes of mesial temporal sclerosis on histological examination tended to have lower MTR values than those patients that had minimal or no changes of hippocampi. When we regarded it abnormal if normalized MTR value was lower than 0.62, the 3 patients were false negative. Magnetization transfer imaging is new MR techniques that has improved sensitivity in the detection and lateralization of mesial temporal sclerosis with temporal lobe epilepsy and also it can provide quantitative information on tissue structure.