| Objective: To investigate the proliferative plasticity of pyramidal tract fibers in bilateral internal capsule, corona radiate and centrum semiovale of patients following a unilateral focal pontine infarction with diffusion tensor imaging which is used to observe the micro-structure changes of fiber bundles.And to discuss its potential impact on neurological recovery.Methods: Twelve patients between the ages of 18 to 65 years old who was in .7 days after the first time of unilateral focal pontine infarction, and had fully conscious going with obvious limb movement function defect symtoms were recruited continuously as the experimental group. Twelve gender and age match healthy volunteers were chosen as the control group. The experimental patients underwent DTI at the first week(W1), the fourth(W 4) and twelfth week(W12)after onset of stroke, respectively. The National Institutes of Health Stroke Scale(NIHSS) , Fugl-Meyer(FM) scale, and Barthel Index (BI) scale were used at 2 hours before DTI examination to estimate the neurological function deficits, the central limb movement function defect, and the ability of daily living. And using the Modified Rankin Scale(mRS) evaluated the prognosis of neurological function at W12. Volunteers underwent one time of DTI. Then, all the DTI images were processed after the completion of DTI. ROIs were setted at pyramidal tract fibers running regional of bilateral internal capsule, corona radiate and centrum semiovale of experimental patients and control volunteers in the BO axis map. Fractional anisotropy and mean diffusivity of ROIs were measured. The relationship between the percent change [(W12- W1) / W1] x 100% of DTI parameter values and of nerve function score was discussed. As the lesion of experimental group patients was in the left or right side, therefore, the mean of left and right sides was adoptted as the data of control group volunteers to analysis statistical data. The DTI parameter data comparison of the experimental group and control group used the two independents ample t-test. The nerve function score and DTI parameter data comparison of the experimental group between different time points used repetitive measure analysis of variance to find the overall differences, then using the LSD method compared the data of different time points.Results: (1) During the observation period, the neurological function of experimental group patients recoveried gradually, and NIHSS score decreased gradually over time(W1 vs W4 vs W12: 11.42±2.15 vs 6.33±2.06 vs 3.75±1.54,P < 0.05). FM score increased gradually over time (W1 vs W4 vs W12:52.92±6.92 vs 71.42±14.35 vs 86.25±11.39, P < 0.05) . BI score increased gradually over time (W1 vs W4 vs W12: 52.08±3.96 vs 71.67±11.35 vs 83.33±8.88, P < 0.05) . (2) Compared with the controls, the FA values in ipsilateral internal capsule and corona radiate of experiment group patients significantly increased at W12(,P < 0.05), and centrum semiovale of experiment group patients significantly increased at W4 and W12 (P < 0.05).Ipsilateral internal capsule vs the controls: (W12: 0.71±0.04 vs 0.60±0.02, P < 0.05),ipsilateral corona radiate vs the controls: (W12: 0.56±0.01 vs 0.46±0.02, P <0.05) , ipsilateral centrum semiovale vs the controls: (W4: 0.39±0.02 vs 0.38±0.01, P <0.05, W12:0.44±0.02 vs 0.38±0.01, P < 0.05) . But MD remained unchange.(3) Compared with the controls, the FA values in contralateral internal capsule, corona radiate and centrum semiovale of experiment group patients significantly increased at W12(P < 0.05).Contralateral internal capsule vs the controls: ( W12: 0.69±0.03 vs 0.60±0.02, P< 0.05), contralateral corona radiate vs the controls: (W12: 0.56±0.01 vs 0.46±0.02, P < 0.05), contralateral centrum semiovale vs the controls: (W12:0.44±0.02 vs 0.381±0.01, P < 0.05 ).But MD remained unchange.(4) Compared with the FA values in the ipsilateral of experiment group patients of the same level at different time-points, the FA values in ipsilateral internal capsule, corona radiate and centrum semiovale of experiment group patients increased gradually over time. The FA values in ipsilateral internal capsule and corona radiate of experiment group patients increased significantly at W12 (P < 0.05) ,and the FA values in ipsilateral centrum semiovale of experiment group patients increased significantly at W4 and W12 (P < 0.05). The comparisons of the FA values in ipsilateral internal capsule at W12,W1 and W4 (W12 vs W1: 0.71 ±0.04 vs 0.60±0.03,W12 vs W4: 0.71±0.04 vs 0.64±0.02, < 0.05) were statistically difference, and the comparison of the FA values in ipsilateral internal capsule at W1 and W4 was not statistically difference,but the FA values in ipsilateral internal capsule at W1 was higher. The comparisons of the FA values in ipsilateral corona radiate at W12 , W1 and W4 ( W12 vs W1: 0.56±0.01 vs 0.47±0.01, W12 vs W4:0.5610.01 vs 0.5010.02 ,P < 0.05) , and the comparison of the FA values in ipsilateral corona radiate at W1 and W4 was not statistically difiference,but the FA values in ipsilateral corona radiate at W1 was higher. The comparisons of the FA values in ipsilateral centrum semiovale at W12,W1 and W4 ( W12 vs W1: 0.44±0.02 vs 0.37±0.02, W12 vs W4:0.44±0.02 vs 0.39±0.02 , < 0.05),and the comparison of the FA values in ipsilateral centrum semiovale at W1 and W4 were statistically difference.(5)Compared with the FA values in the contralateral of experiment group patients of the same level at different time-points, the FA values in internal capsule,corona radiate and centrum semiovale of experiment group patients increased gradually over time.The FA values in contralateral internal capsule, corona radiate and centrum semiovale of experiment group patients increased significantly at W12 (P < 0.05). The comparisons of the FA values in contralateral internal capsule at W12 , W1 and W4 (W12 vs W1: 0.69±0.03 vs 0.61 ±0.03,W12 vs W4: 0.69:t±0.03 vs 0.65±0.03,P < 0.05) were statistically difference, and the comparison of the FA values in contralateral internal capsule at W1 and W4 was not statistically difference,but the FA values in contralateral internal capsule at W1 was higher. The comparisons of the FA values in contralateral corona radiate at W12,W1 and W4 (W12 vs W1: 0.56±0.01 vs 0.47±0.03,W12 vs W4: 0.56±0.01 vs 0.51±0.03, < 0.05) were statistically difference, and the comparison of the FA values in contralateral corona radiate at W1 and W4 was not statistically difference,but the FA values in contralateral corona radiate at W1 was higher. The comparisons of the FA values in contralateral centrum semiovale at W12 , W1 and W4 (W12 vs W1: 0.44±0.02 vs 0.37±0.02,W12 vs W4: 0.44±0.02 vs 0.41±0.01.P< 0.05) were statistically difference, and the comparison of the FA values in contralateral centrum semiovale at W1 and W4 was not statistically difference,but the FA values in contralateral centrum semiovale at W1 was higher. (6) The percent change of FA values in bilateral internal capsule, corona radiate and centrum semiovale of patients associated positively with the percent change of FM. The percent change of FA values in ipsilateral internal capsule, bilateral corona radiate and centrum semiovale of patients associated positively with the percent change of BI(P < 0.05) and negatively with the percent change of NIHSS(P < 0.05) . But the percent change of FA values in contralateral internal capsule and the percent change of NIHSS and BI had no correlation.Conclusion: (1)The proliferative plasticity of pyramidal tract fibers occurred in the bilateral internal capsule, corona radiate and centrum semiovale,which was increasingly obvious over time.(2) The percent change of FA values in bilateral internal capsule, bilateral corona radiate and centrum semiovale of patients associated positively with the percent change of FM. The percent change of FA values in ipsilateral internal capsule, bilateral corona radiate and centrum semiovale of patients associated positively with the percent change of BI(P< 0.05) and negatively with the percent change of NIHSS(P< 0.05).Which prompted that the proliferative plasticity of pyramidal tract fibers may be beneficial to the recovery of neurological function. |
