| PART ONE The sCST analysis and ROI analysis for the mechanism and function prediction on the completely paralyzed hands of chronic stroke patientsOBJECTIVE:Many hands of the affected side are completely paralyzed hands after stroke. It affects the activities of daily living severely. It’s not clear why it happened and how to predict it. Previous studies have indicated that diffusion tensor imaging (DTI) can reveal the Wallerian degeneration (WD) of neural fibers, and the parameters of DTI are relative to the clinical outcomes of stroke patients. However, there’re no studies of completely paralyzed hands using DTI. Whether the DTI parameters have predictive values for the outcome of hand function in chronic stroke has not been identified completely. In order to explore the correlations between hand motor outcome and DTI parameters for chronic stroke patients, reveal the cause of completely paralyzed hands and find the predictive factors of hand function, we perform this study using sCST analysis and pure ROI analysis of DTI.METHODS:Thirty-three chronic stroke patients were divided into two groups:the CPH (completely paralyzed hands) group (17patients) and the PPH (partially paralyzed hands) group (16patients). Patients were evaluated by the Fugl-Meyer Assessment (FMA), the National Institutes of Health Stroke Scale (NIHSS) and12level hemiplegia evaluation. In this study, all the patients underwent diffusion tensor imaging by3.0T MRI. We investigated a series of DTI parameters (rFA,rλ1, rλ23, rMD) between the CPH group and the PPH group by two analysis methods (sCST analysis and pure ROI analysis). The difference of DTI parameters between the affected side and the unaffected side and the difference of DTI parameters between the CPH group and the PPH group were analyzed. In addition, the Spearman correlation test was performed to assess the possible correlations between the values of rFA, rλ1, rλ23and rMD of the sCST and the clinical score. RESULTS:In the CPH group, there were significant decreases of the FA and significant increases of the A23and MD in the affected sCST (p<0.01). There were no significant differences between the affected side and the unaffected side for the λ1(p>0.05). In the PPH group, there were significant decreases of the FA and significant increases of the A23in the affected sCST (p<0.01). There were no significant differences for the λ1and MD (p>0.05). In addition, the rFA of CPH group(0.725+0.120) was significantly lower than that of PPH group(0.876±0.079)(p<0.01). The rA23of CPH group(1.565±0.390) was significantly higher than that of PPH group(1.244±0.258)(p<0.01). In contrast, there were no significant differences between the CPH group and PPH group for the rλ1and rMD (p>0.05).In pure ROI analysis of cerebral peduncle, the rA23of CPH group (1.387±0.202) was significantly higher than that of PPH group (1.128±0.244)(p<0.05). The rMD of CPH group (1.144±0.091) was also significantly higher than that of PPH group(1.010±0.135)(p<0.05). In contrast, there were no significant differences between the CPH group and PPH group for the rFA and rλ1(p>0.05). In addition, there were no significant differences between the CPH group(0.634±0.194) and PPH group(0.745±0.134) for the rSROi (p>0.05).In the correlation analysis, we found that the rFA was correlated with the NIHSS(r=-0.44, p=0.010), the FMA(upper limb)(r=0.51, p=0.002), the FMA(wrist)(r=0.463, p=0.007), the FMA(hand)(r=0.422, p=0.014), the FMA(wrist and hand)(r=0.433, p=0.012), the12level hemiplegia evaluation(upper limb)(r=0.543, p=0.001) and the12level hemiplegia evaluation(hand)(r=0.521, p=0.002). The rλ23was correlated with the NIHSS (r=0.374, p=0.032), the FMA(upper limb)(r=-0.367, p=0.035), the FMA(wrist)(r±0.453, p=0.008), the12level hemiplegia evaluation(upper limb)(r=-0.393, p=0.024) and the12level hemiplegia evaluation(hand)(r=-0.47, p=0.006). However, there were no significant correlations between the rλ23and the FMA(hand) or the FMA(wrist and hand)(p>0.05). Moreover, there were no significant correlations between the rλ1or the rMD and the clinical scores (p>0.05). In addition, we did not find any significant correlations between the DTI parameters and the FMA(lower limb)(p>0.05).CONCLUSIONS:1.There were significant decreases of the FA and significant increases of the A23in the affected sCST. It indicated the decreasing anisotropy of the segment of the corticospinal tract. The increasing of the λ23may be the cause of the decreasing of the FA.2.There were significant decreases of the rFA and significant increases of the rA23in the sCST of CPH group. There were significant decreases of the rA23and the rMD in the ROI (cerebral peduncle) of CPH group. It indicated that the lesion of the myelin sheath and the integrity of CST are more severe. The severity of injury might correlate with the completely paralyzed hands.3.The rFA and rA23of sCST might have predictive values for evaluating the hand function outcomes of stroke patients. The higher the rFA, the lower the rA23, hand function is better and the neural function defect is less. PART TWO The VBM analysis for the mechanism and function prediction on the completely paralyzed hands of chronic stroke patientsOBJECTIVE:Previous studies have indicated that some parameters of diffusion tensor imaging (DTI) are relative to the clinical outcomes of stroke patients. However, there’re no DTI studies of the whole brain about the completely paralyzed hands after stroke. In order to explore the correlations between hand motor outcome and Wallerian degeneration in the whole brain for chronic stroke patients, and reveal the mechanism of the completely paralyzed hands, we perform this study using VBM analysis of DTI.METHODS:Twleve healthy people were included in the HC group. Twenty-three chronic stroke patients were divided into two groups:the CPH group (completely paralyzed hands,11patients) and the PPH group (partially paralyzed hands,12patients). Patients were evaluated by the Fugl-Meyer Assessment (FMA). In this study, all the subjects underwent diffusion tensor imaging by3.0T MRI. The VBM analysis were performed by the software SPM. Two sample t test for smoothed maps of diffusion indices was carried out between each pair of the three groups. The regions with significant differences of FA map were made as binary masks, which were applied to all participants respectively. Then, individual ROI value of each region was obtained by averaging FA value of all voxels within each mask. The precedure of processing MD, AD and RD was the same as FA. In addition, the Spearman correlation test was performed to assess the possible correlations between the values of the DTI parameters and the FMA score.RESULTS:Compared with the PPH group, it was found that in the CPH group there were significant decreases of the FA in the ipsilateral brainstem, sub-lobar, precentral gyrus, medial frontal gyrus(MFG), supplementary motor area(SMA), superior temporal gyrus, parietal lobe and occipital lobe, and the contralateral postcentral gyrus. There were significant increases of the MD and AD in the ipsilateral sub-lobar. In addition, there were significant increases of the RD in the ipsilateral sub-lobar and brainstem. Compared with the HC group, the range of the regions with significant differences of DTI parameters in the CPH group were significantly wider than in the PPH group.In the correlation analysis, we found that the FMA score (wrist and hand) was correlated with the FA of the ipsilateral brainstem (r=0.83, p<0.01) sub-lobar (r=0.90, p<0.01), precentral gyrus (r=0.84, p<0.01), MFG (r=0.79, p<0.01), SMA(r=0.69, p<0.01)and the contralateral postcentral gyrus(r=0.80, p<0.01). In addition, the FMA score (wrist and hand) was correlated with the MD (r=-0.84, p<0.01) and AD (r=-0.77, p<0.01) of the ipsilateral sub-lobar. The FMA score (wrist and hand) was also correlated with the RD of the ipsilateral brainstem (r=-0.69, p<0.01) and sub-lobar (r=-0.86, p<0.01)CONCLUSIONS:1. There were significant decreases of the FA in the ipsilateral brainstem, sub-lobar, precentral gyrus, medial frontal gyrus (MFG), supplementary motor area (SMA), superior temporal gyrus, parietal lobe and occipital lobe, and the contralateral postcentral gyrus in the CPH group. There were significant increases of the MD and AD in the ipsilateral sub-lobar, and the RD in the ipsilateral sub-lobar and brainstem in the CPH group.2. The Wallerian degeneration of the ipsilateral brainstem and sub-lobar played an important role in the completely paralyzed hands. The Wallerian degeneration of the ipsilateral precentral gyrus, MFG, SMA, superior temporal gyrus, parietal lobe and occipital lobe, and the contralateral postcentral gyrus were also the important factors which effect the hand function outcomes after stroke.3. There were some parameters which might have predictive values for evaluating the hand function outcomes after stroke:the FA and RD of the ipsilateral brainstem, the FA, MD, AD and RD of the ipsilateral sub-lobar, and the FA of the ipsilateral precentral gyrus, MFG, SMA and the contralateral postcentral gyrus. |
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