Study Of Morphology And White Matter Of Hippocampus On MRI Of Primary Epilepsy

[Objective]Using diffusion tensor imaging to investigate the structural feature of white matte of medial aspect of temporal lobe in primary epilepsy, combination of HCV measurement with three-dimensional volumetric software, the purpose of this study was to observe changes of volume and white matter of hippocampus, and provide functional anatomy basis for the clinical practice.[Methods]Both the health group (30 healthy volunteers) and the patient group (30 primary epilepsy patients) were performed by MRI normal scan:TlWI,T2WI,FLAIR, exclusion of intracerebral lesion. Their cognitive function were evaluated by mini-mental state examination (MMSE). The patient group was divided into two groups:the moderate frequency of epileptic seizures group and the high frequency of epileptic seizures group, according to the seizure frequency. All of objective were scanned by DTI and 3D-FSPGR. The data of DTI was post-processed in SUN ADW 4.0 Advantage workstation.the average diffusion coefficient (DCavg), fractional anisotropy (FA), relative anisotropy (RA) and anisotropy index (AI) of ROI (hippocampal head (HH), hippocampal body (HB), hippocampal tail (HT) of both left and righ temporal lobe white matter and amygdaloid body) were measured. Hippocampal volume (HCV) of all of objective were calculated with three-dimensional volumetric software. All of statistical treatments were carried out by SPSS16.0 software. DTI parameters and HCV of corresponding regions were compared by ANOVA among three groups. The relationship of MMSE scores, HCV and DTI parameter were analyzed by pearson's correlation, p value less than 0.05 was considerde as statistical significance. [Results]1.In control subjects, the mean volume of right and left hippocampus, HCV ratio of right side to left side and HCV ratio of smaller side to bigger side were 3.677 cm~3, 3.515 cm3,1.047 and 0.956 respectively; HCVs of right hippocampus was bigger than that of the left hippocampus (p<0.05).2.HCVs of right side and left side, HCV ratio of smaller side to bigger side in the moderate frequency and the high frequency of epileptic seizures group were smaller than them in control group (p<0.05).3.In control subjects, there were no statistically significant differences in Dcvag, FA, RA, AI between the right and left hippocampus. No significant differences among three parts of hippocampus for DCavg, FA, RA, AI were found.4.Comparion of each of DTI parameter among head, body and tail of hippocampus in primary epilepsy.③In the moderate frequency of epileptic seizures group:The DCavg of right and left HH was bigger than in HB (p<0.05), The DCavg of right HT was bigger than in HB (p<0.05). No significant differences for FA, RA and AI were found (p>0.05).②In the high frequency of epileptic seizures group:The DCavg of left HH was bigger than in HB (F=2.458,p<0.05). It is the same too, between the RA of left HH and HB (F=2.128,p<0.05).5.Correlation analysis of HCV and DTI parameters in primary epilepsy:The relationship of DCavg in HH and HCVs of left side has negative correlation (r =-0.706, p<0.01); Positive correlations between FA in HH and HCVs of left side (r =0.649,p<0.01).6. Each parameter of DTI in the hippocampus among three groups.①The DCavg value of hippocampus in the moderate frequency and the high frequency of epileptic seizures group was higher than in control group. The DCavg of right HH and HT had significant differences among three groups (p=0.000,0.001). A significant increase in DCavg of left HH and HT were found in the primary epilepsy group compaired with the health group, with p<0.05.②The FA and RA value of right HH and HT in the moderate frequency and the high frequency of epileptic seizures group was lower than in control group (p<0.001). The FA and RA value of left HH and HT had significant differences among three groups (p<0.05).③The AI value of right HH in the high frequency of epileptic seizures group was lower than in control group (p=0.0035). The AI value of right and left HT in the moderate frequency of epileptic seizures group was lower than in control group (p =0.047,0.041).7. Relativity analysis of cognitive function and HCV and parameters of DTI①he average of MMSE scores was 29.100±0.923 in control group, 25.533±1.552 in the moderate frequency of epileptic seizures group,23.539±1.808 in the high frequency of epileptic seizures group. They had statistically significant differences among three groups (p<0.05).②egative correlation betwene MMSE and DCavg in HH of left side, positive correlation betwene MMSE and FA in HH of left side in primary epilepsy (r=-0.665, 0.495, p<0.01). The relationship of MMSE and HCVs of left side has positive correlation (r=-0.627,p<0.01).[Conclusion]Diffusion changes in hippocampus of patients with primary epilepsy were different, the DCavg is sensitively than FA, RA and AI, and the head of hippocampus showed the more abmormal Dcavg;hippocampal volume measurement with three-dimensional volumetric software can provide the information of bilateral hippocampal formation;no statistically significant differences between the right and left hippocampus for each parameter of DTI were found in control subjects;HCV has good correlation with Dcavg and FA;hippocampus change was related to the cognition impairment of epilepsy;DTI technology combining with hippocampal volume measured three-dimensional reconstruction can investigate changes of volume and white matter of hippocampus and provide functional anatomy basis for clinical practice.