Relation Between Fractional Anisotropy Of Postcentral Gyrus Subcortex And Somatosensory Evoked Potentials After Acute Posterior Limb Of Internal Capsule Infarction

The nerve fibers connected to the infarct after focal cerebral infarction occurs Wallerian degeneration such as axonal decomposition, demyelination etc.Resulting the adverse effects on the patient’s neurological function recovery. In recent years, a lots of reseach of Wallerian degenerion in corticospinal after cerebral infarction and Relationship between the Wallerian degenerion and motor disturbance.but the reseach about Wallerian degenerion at sensory pathway after cerebral infarction was very few.The internal capsule is fibers contact the cortex and cortex-central in the concentrated part of the brain.Internal capsule thalamus radiation issued from thalamus and terminate in postcentral gyrus subcortex. postcentral gyrus subcortex at the route of thalamus. internal capsule is the concentrated part of the sense-conducting fibers. FA (fractional anisotropy) reflect the white matter fiber in arrangement tightness and integrity of the myelin, postcentral gyrus subcortex was the distant sites connected infarct after acute posterior limb of internal capsule infarction. Sensory pathway occurs the Wallerian degeneration by detcet the FA after acute posterior limb of internal capsule infarction. Explore the relationship change course of FA and recovery of sensory function.Somatosensory evoked potentials(SEP),was nerve impulses recorded potential changes along sensory nerve pathways to the cortical areas (postcentral gyrus) after give peripheral nerve or skin proper electrical stimulation.magnetic stimulation or physiological stimulation. SEP was a noninvasive method reflect the functional status of sensory nerve pathways. We speculated that the FA and SEP is consistent at reflect the sensory pathways and sensory function.Patients were grouped according to the detection and grading standards on the SEP, reseach the regulation of FA.sensory disturbance rating and the SEP grouping, Reveal the complementary of the FA and the SEP on the prediction of sensory function.Part1Relation between fractional anisotropy of postcentral gyrus subcortex and somatosensory evoked potentials after acute posterior limb of internal capsule infarctionContents and methods:Explore the postcentral gyrus subcortical white matter FA after acute posterior limb of internal capsule infarctio in each group grouped by SEP grading standards, and the relationship between the FA and the sensory disturbance rating.31patients grouped SEP normal group. Mild-to-moderate abnormal group and severe abnormal group.underwent DTI to obtain the FA in the white matter region of postcentral gyrus subcortical of normal and diseased side.and evaluation with the sensory disturbance rating. Results:A total of31patients, SEP normal group (n=7), the SEP mild to moderately abnormal group (n=15), and SEP severe abnormal group (n=9):1. The postcentral gyrus subcortical FA in diseased side of SEP normal group. SEP mild to moderate abnormal group and SEP severe abnormal group was significant difference (F=9.709. P=0.001); the FA in the SEP severe abnormal group and SEP mild to moderately abnormal group were significantly lower than SEP normal group, the FA in SEP severe abnormal group was significantly lower than SEP mild to moderately abnormal group, the FA in healthy side in three SEP groups was no significant difference.2. The postcentral gyrus subcortical FA in diseased side in each groups significantly lower than the healthy side(P<0.000):the CCT in diseased side was significantly prolonged than in healthy side(t=-7.445, p=0.000). in SEP mild to moderate abnormal group the diseased side FA was significantly correlated with CCT(r=-0.821, p=0.000).3. The degree of sensory function was significantly correlated with the SEP grouping standard (r=0.520, p=0.003), the sensory disturbance heavier, the SEP abnormalities higher, between the two was statistically significant (χ2=10.383, P=0.034).Summary:1. The postcentral gyrus subcortical FA in diseased side of SEP normal group, SEP mild to moderate abnormal group and SEP severe abnormal group was significant difference. the SEP abnormalities higher, the FA lower.2. The postcentral gyrus subcortical FA in diseased side of SEP normal group. SEP mild to moderate abnormal group, SEP severe abnormal group were significantly lower than in healthy side. 3. In SEP mild to moderate abnormal group the diseased side FA was significantly correlated with CCT. the degree of sensory function was significantly correlated with the SEP grouping standard.Part2The following up study of FA in postcentral gyrus subcortex after acute posterior limb of internal capsule infarctionContents and methods:Explore the dynamic changes of FA in postcentral gyrus subcortical white matter after acute posterior limb of internal capsule infarction, and the relationship between the dynamic changes and recovery of Function sensory. The31patients in part1evaluation with the sensory disturbance rating and underwent DTI in the2nd week(W2),1months(M1),3months(M3),6months(M6) and12months(M12) respectively.Results:1. The postcentral gyrus subcortical FA in diseased side of SEP normal group was significantly difference between different periods(F=14.583, P=0.003). the FA decrease from the2nd weeks to1month. After1month, the FA was no significantly diffenerece between different periods.2. The postcentral gyrus subcortical FA in diseased side of SEP mild to moderate abnormal group was progressively difference between different periods (F=122.624. P=0.000). the FA decrease from the2nd weeks to3months was significantly. Only6months and12months the FA compared difference was not significant (P=0.200), the other phases, the difference was significantly difference (P<0.05). The sensory disturdance rating was significantly difference between different periods.(F=26.534, P-0.000) after3months of sensory disturbance rating increased significantly difference, Only2rd weeks and1months compared difference was not significant (P=0.055).3. The postcentral gyrus subcortical FA in diseased side of SEP severe abnormal group was progressively decreae in different periods(P<0.05),The sensory disturdance rating was significantly difference between different periods (F=20.030, P=0.000). the difference in2rd weeks and1months compared,1months and3months compared.2rd weeks and3months compared, was not significant (P>0.005), and other periods compared to the difference was significantly.4. The postcentral gyrus subcortical FA in diseased side of SEP normal group. SEP mild to moderate abnormal group, SEP severe abnormal group were significantly lower than the FA in the healty side in the different periods. The FA in diseased side of SEP normal group, SEP mild to moderate abnormal group, SEP severe abnormal group were significantly difference.5. The percent changes of diseased side FA in each SEP group was significantly correlated with the percent changes of sensory disturdance rating.Summary:1. In SEP normal group, the postcentral gyrus subcortical FA in diseased side decrease to the1months,the sensory disturdance rating was progressively rise in different periods.2. In SEP mild to moderate abnormal group, the postcentral gyrus subcortical FA in diseased side decrease to the3months,the sensory disturdance rating was progressively rise after3months.3. In SEP severe abnormal group, the postcentral gyrus subcortical FA in diseased side decrease to the12months.the sensory disturdance rating was progressively rise after6months.4. The changes of FA greater, the recovery of sensory function poorer. Conclusion1. FA in postcentral gyrus subcortical white matter after acute posterior limb of internal capsule infarction was decrease, the SEP abnormalities higher, the FA lower.2. The SEP abnormalities higher, the degree of sensory disturdance is the heavier.3.The changes of FA in postcentral gyrus subcortical white matter after acute posterior limb of internal capsule infarction of each SEP groups was different, in SEP severe normal group the FA was progressively decrease.