Diffusion Tensor Imaging Study In Temporal Lobe Epilepsy Network

Part I Diffusion tensor imaging of hippocampus and temporal lobe white matter in temporal lobe epilepsyObjective:To evaluate the application value of diffusion tensor imaging in temporal lobe epilepsy.Materials and Methods:25 patients with Temporal Lobe Epilepsy (TLE) (11 hippocampal sclerosis (HS+) and 14 non-hippocampal sclerosis (HS-)) and 15 healthy controls were enrolled in this study. Routine MRI and DTI data with 20 diffusion-gradient-direction were obtained on a 1.5 Tesla Siemens MR imaging scanner. The mean diffusivity (MD) and fractional anisotropy (FA) values were calculated in hippocampus and temporal lobe white matter in all paitents.Result:The MD value of the ipsilateral hippocampus in the HS+ group was much higher than that in the HS- group and the control group. The difference among the three groups was significant statistically (P=0.013). The FA value of the ipsilateral hippocampus in the HS+ group was much lower than that in the HS- group and the control group. The difference between HS+ group and control group was significant statistically (P=0.036). The contralateral hippocampus in the HS+ group was also found the elevation of MD value and reduction of FA value, and their differences with the ipsilateral hippocampus were significant respectively (p=0.036,p=0.018). There was no significant difference of MD values between bilateral hippocampus in the HS- group, but their FA values were significantly different (p=0.001). The MD value of the ipsilateral temporal lobe white matter in the HS+ group was higher than that in the HS- group and the control group. The difference between HS+ group and control group was significant statistically (P=0.024). The FA value of the ipsilateral temporal lobe white matter in the HS+ group was lower than that in the HS- group and the control group, but the difference among the three groups was not significant statistically. In the HS+ group, the MD value of the ipsilateral temporal lobe white matter was higher than that of the contralateral temporal lobe white matter, while the FA value of the ipsilateral side was lower than that of the contralateral side. But they did not reach the statistical significance respectively.Conclusion:TLE patients, including HS+ group and HS- group, have different DTI parameters in hippocampus and temporal lobe white matter. While the MD value showes much more significant changes. DTI has potential application value for lateralization of the TLE, especially in hippocampal sclerosis patients.Part II Diffusion tensor imaging study in temporal lobe epilepsy networkObjective:To evaluate the network in temporal lobe epilepsy using diffusion tensor lmaging.Materials and Methods:25 patients with TLE (11 HS+and 14 HS-) and 15 healthy controls were enrolled in this study. Routine MRI and DTI data with 20 diffusion-gradient-direction were obtained on a 1.5 Tesla Siemens MR imaging scanner. The MD and FA values were calculated in genu of corpus callosum, splenium of corpus callosum, internal capsule, external capsule, thalamus, fornix, cingulum in all paitents on both sides.Result:The MD value of the fornix in the HS+group was higher than that in the HS-group and the control group. The difference among the three groups was significant statistically (P=0.024). The FA value of the fornix in the HS+group was lower than that in the HS- group and the control group, but the difference among the three groups was not significant statistically. The MD value of the ipsilateral anterior limb of the internal capsule in the HS+ group was higher than that in the HS- group and the control group. The difference between HS+ group and control group was significant statistically (P=0.049). The FA value of ipsilateral anterior limb of the internal capsule in the HS+ group was lower than that in the HS- group and the control group, but the difference among the three groups was not significant statistically. The MD value of the ipsilateral external capsule in the HS+ group was higher than that in the HS- group and the control group. The difference between HS+ group and control group was significant statistically (P=0.045). The FA value of ipsilateral external capsule in the HS+ group was lower than that in the HS- group and the control group, but the difference among the three groups was not significant statistically. Reduction of FA value and elevation of MD value were also found on the splenium of corpus callosum in HS+ group, and their differences with the control group were significant respecively (P=0.049,0.019). The MD value of ipsilateral thalamus in the HS+ group was higher than that in the HS- group and the control group, while the FA value was lower. But the differences among the three groups did not reach the statistical significance respectively. FA and MD values in the genu of corpus callosum, the posterior limb of the internal capsul, and the cingulum had no significant differences among the three groups. Conclusion:The abnormalities of water molecular diffusion caused by temporal lobe epilepsy not only affect the temporal lobes, but also affect other cerebral white matter fibers through the epilepsy network. As one of the most important componences of the epilepsy network, the fornix showes the most significant changes of the FA and MD values.