Diffusion Tensor Imaging Shows More Extensive White Matter Changes in Frontal than in Temporal Lobe Epilepsy

Abstract

Introduction: FLE is known to have a poorer prognosis than TLE. We compared the extent of white matter changes in these groups using diffusion tensor imaging-based tractography. Methods: 20 tracts each were made in five TLE and six FLE patients (bilateral FORX, CGC, PH, UF, SLF, ILF, IFOF, ATR, CST; FMajor and FMinor) and their FA values compared. Results: The TLE group had decreased FA of all ipsilateral fibres except IFOF, with a statistically significant decrease in FORX and UF. The FLE group had a significant decrease (p< 0.05) in the FA values of contralateral ATR and CST. A few contralateral tracts (PH, UF, SLF, IFOF) and ipsilateral FORX and ILF also showed (statistically nonsignificant) decreased mean FA. Mann-Whitney U test comparing ipsilateral nine fibre pairs of FLE vs. TLE was non-significant and significant (p<0.05) only for CST in contralateral fibre comparison. However, a generalised decrease in all fibre FA in FLE vs. TLE was noticed, except for the ‘intimate’ temporal fibres, viz., FORX and PH. The mean FA of all tracts was 0.4982 and 0.5201 for FLE and TLE, respectively (p<0.05). The mean FMajor and FMinor FA were 0.6146 vs. 0.6702 and 0.5598 vs. 0.5917 in FLE vs. TLE, respectively. Conclusion: Tractography based FA value comparison reveals more extensive and severe white matter changes in FLE than in TLE.