Study Of Diffusion Tensor Image In Patients With Postherpetic Neuralgia

Objectives:To get the internal regularity and changing property of localized microstr-ucture of white matter of PHN and offer the basic research support for thebetter therapy of PHN by studying the abnormal diffusion of the brainwhite matter in patients with PHN.Methods：Eight PHN patients and eight healthy subjects which were matched for ageand sexuality were included in the study and examined with a routine3.0T magnetic resonance imaging scanner.All Data were processedautomatically by a sofrware called PANDA,which were designed by thenational key laboratory of cerebral cognition and learning in BeijingNormal University.Whole-head DTI scans measuring FA、MD、λ1and λ23were analyzed in group with track-based spatial statistics（TBSS）.Voxel-wise group comparisons were performed usingnon-parametric、two-sample t-test. In order to explore the internal clinicalregularity of the abnormal diffusion of cerebral white matter in patientwith PHN correlation among the change of diffusion property、diseaseduration、VAS score were analyzed with partial correlation analysis.Results： The result of mean diffusion indices of white matter skeletons in the wholebrain showed that the PHN patients had no significant changes in theparameters of fractional anisotropy (FA, P=0.646、axial diffusivity(λ1,P=0.871) and radial diffusivity(λ23,P=0.837)、mean diffusivity(MD=0.899)compaired with the healthy controls. But significant decrease in localbrain white matters of the patients group were observed in two sides ofprimary somatosensory cortex (SⅠ)、occipital lobe、insula、cerebellum and precentral gyrus，in left side of secondary somatosensory cortex(SⅡ)、callosum、parahippocampal gyrus、thalamus、upper frontal gyrusand orbitofrontal gyrus,in the right side of amygdala、fornix and middlefrontal gyrus（significant difference:p <0.05, uncorrected by FWE）.The results of partial Correlation analysis showed that the changes ofFA(p=0.002, r=-0.935) and λ1(p=0.003,r=-0.921)had significantlypositive correlationships with disease duration. VAS score had nosignificant correlationship with disease duration(P=0.166)and FA(P=0.234)、λ1(p=0.243)(significant difference: p<0.05).Conclusion:The brain white matter in patients with PHN was abnormal in microstru-cture in local brain white matter compaired with normal controls, all thesechanges had highly positive correlationships with disease duration,whichinvolved internal and external system including brain white matter indouble sides of primary somatosensory cortex(SⅠ)、insula，left side ofcallosum、 thalamus、 upper frontal gyrus and orbitofrontal gyrus、pre-central gyrus,right side of middle frontal gyrus.All the abnormaldiffusions in the above brain regions may participate in the generation ofPHN.