MR diffusion tensor imaging and MRI diffusion-tensor tracking of medial structures of the temporal lobe in the diagnosis of temporal lobe epilepsy

Abstract

Objective To investigate the parameter values and changes of local fiber bundles of the medial structures of the temporal lobe in patients with temporal lobe epilepsy(TLE) with MR diffusion tensor imaging(DTI)and MRI diffusion-tensor tracking(DTT),and evaluate the diagnostic value of DTI in the localization of seizure focus in patients with TLE:Methods Sixteen patients with TLE,admitted to our hospital from December 2010 to February 2011,and 20 healthy volunteers received conventional MRI and DTI.The values of apparent diffusion coefient(ADC),fractional anisotropy(FA)and relative anisotropy(RA) of the bilateral medial structures of the temporal lobe (including the amygdala,hippocampus and cortex)were measured,respectively.The differences of the fiber bundles between the epilepsy patients and the controls were observed with DTT.Results No significant differences in measured values of ADC,FA and RA were noted between the left and right medial structures of temporal lobe in the controls(P＞0.05).The values of ADC,FA and RA in the left/right medial structures of temporal lobe in TLE patients had significant differences as compred with those in controls(P＜ 0.05); the values of ADC showed gradual reduction in the ipsilateral side,contralateral side and controls,successively; and the changes in the hippocampus tail was the most obvious.The values of FA and RA showed gradual increment in the ipsilateral side,contralateral side and controls successively;the changes of parameters values in the amygdala and the hippocampus body were more remarkable than those in the hippocampus tail.Conclusion The DTI can show the micromechanics′ characteristics of the medial structures of the temporal lobe in patients with TLE,which can help the location of seizure focus in patients with TLE.Increasing the understanding of the medial structures of the temporal lobe will help the preoperative integral assessment and improve the surgical effect. Key words: Temporal lobe epilepsy; , Diffusion tensor imaging; Diffusion-tensor tracking; Hippocampal sclerosis