Role of Diffusion Tensor Imaging in Detection and Lateralization of Temporal Lobe Epilepsy

Abstract
Background: Temporal lobe epilepsy (TLE) is the most common localization related epilepsy syndrome. Diffusion tensor imaging (DTI) is a new imaging technique that is sensitive to the structural integrity changes of cerebral tissue in patients with TLE who have been evaluated for epilepsy surgery.
Aim of Study: To demonstrate the role of diffusion tensor imaging in the diagnosis of temporal lobe epilepsy.
Patients and Methods: This is a prospective study included 40 patients diagnosed clinically as having TLE and twenty control subjects. The patients and control groups are examined by conventional magnetic resonance imaging (MRI ) followed by DTI and tractography. EEG examination, was performed to 36 patients only, the remaining 4 were missed during follow-up. It was done to support the clinical diagnosis of TLE and to help in the lateralization of the site of seizure focus to be compared with DTI results.
Results: The calculated cut off value regarding fractional anisotropy (FA )difference between both hippocampi was 0.014. Twenty eight patients with FA differences above this value were considered as DTI positive of hippocampal abnor-mality and 12 patients were below this value and were con-sidered as DTI negative. FA differences between both hippoc-ampi in patients' group were significantly increased as compared with the control group.
Conclusion: DTI can detect hippocampal abnormalities even in patients with normal conventional MR, so it can be used to lateralize seizure side, thus increase the diagnostic accuracy before epilepsy surgery.