观察脑肿瘤致大脑运动功能重组患者运动神经网络变化的功能性连接MRI研究

目的 应用功能性连接MR成像(fcMRI)技术,观察中央沟附近脑肿瘤所致功能重组患者运动神经网络的改变,为理解肿瘤所致运动功能重组的机制提供新的实验依据.方法 采用1.5 T MR成像系统,对6名正常志愿者及14例功能MRI(fMRI)显示运动功能重组的中央沟附近脑肿瘤患者行fcMRI.分别得到以正常受试者左和右主运动(M1)区、脑肿瘤患者肿瘤侧半球和非肿瘤侧半球M1区为种子体素(兴趣区)的功能连接图.对与以上种子体素呈明显相关的功能连接区的位置、范围、体积进行评估.将所测数据进行t检验和单向方差分析.结果 fcMRI显示6名正常志愿者单侧M1区的功能连接脑区遍布于双侧大脑半球,包括双侧M1区、双侧辅助运动区(SMA)、双侧运动前区(PMC区)等与运动相关的皮层,左右对称分布.左M1区的功能连接区(9514.17±186.92)mm3]与右M1区者(9364.67±382.75)mm3]范围基本一致,二者在体积上差异无统计学意义(P>0.05);肿瘤组fcMRI显示:(1)与肿瘤侧M1区所连接脑区的体积(11193.14±811.29)mm3]明显大于非肿瘤侧M1区的功能连接区(6549.86±400.94)mm3](P<0.01).肿瘤组肿瘤侧M1区所连接的脑区与正常对照组单侧M1区的功能连接脑区差异有统计学意义(P<0.01),前者明显扩大(P<0.01),提示肿瘤侧M1区与其他运动相关脑区的功能连接增强.其连接脑区的范围与受累手对指运动时同层面fMRI显示的运动功能重组区范围基本一致.(2)肿瘤组非肿瘤侧M1区的功能连接区的体积与正常组比较,差异有统计学意义(P<0.01),前者有减少的趋势(P<0.01),特别是肿瘤侧半球内,提示非肿瘤侧M1区与对侧半球的功能连接破坏.结论 肿瘤组患者肿瘤侧M1区功能连接区的增多提示运动功能重组可能与运动功能传导路径重组或潜在运动路径补偿性开放有关.fcMRI是一种显示颅内肿瘤所致运动神经网络变化的有效手段.

Function connectivity MRI to evaluate the changes of the motorial nerve net in patients with brain tumors adjacent to the central sulcus occurred with reorganization of motor function

Objective We investigated the changes of the motorial network in patients suffered from brain tumors adjacent to the central sulcus occurred with reorganization of motor function using function connectivity MRI(fcMRI)technique in order to provide the new evidence for the compensational hypothesis of the reorganization caused by focal lesions.Methods Using 1.5 T MRI unit,14 patients with brain tumors in the vicinity of the central sulcus occurred with reorganization of motor function and 6 normal volunteers were examined with fcMRI technique while the subjects performed no task.By selecting seed voxels(region of interest)in the regions showing the most activation in M1 area on the activated map and cross correlating with every voxel within the brain,the fcMRI maps based on unilateral primary motor(M1)area were calculated.The location,extent and volume of the region showing significant connectivity to the several seed voxel,such as left/right M1 area in the health group and affected/unaffected M1 area in the patient group were evaluated on the fcMRI map.Results In healthy group,the extent and volume of the region showing significant connectivity to the left M1 area(9514.17±186.92)mm3]were almost similar to those to the right M1 area (9364.67±382.75)mm3].There showed no significant difference in motor connectivity between the two groups(P>0.05).In the tumor group,the volume of regions showing significant connectivity to the M1 area located in the affected hemisphere (11193.14±811.29)mm3]was obviously higher than that of regions based on the seed voxel in the unaffected side(6549.86±400.94)mm3](t=20.383,P＜0.01).The volume was significantly different among the regions showing high connectivity to the M1 of the affected side in patient group.those showing significant connectivity to the left M1 and fight M1 in health group(P＜0.01),the former was the biggest(P＜0.01).The extent of the regions showing connectivity to the affected M1 was consistent with the reorganization area of motor function revealed by fMRI.The volume of regions showing significant connectivity to M1 area of unaffected hemisphere in patient group showed significant difference compared with those showing significant connectivity to the left M1 and right M1 in health group(P＜0.01),the former was smallest(LSD,P＜0.01).especially in the affected hemisphere.It might mean the disrupted functional connectivity between the M1 area of unaffected hemisphere in patient group and motor area located in the collateral side.Conclusion The increased connectivity between the M1 area of the affected hemisphere and the other motor cortex might indicate that the reorganization in the motor pathway and the formation of the potential compensatory network second to the impairment of the normal motor pathway resulted in the functional reorganization of the motor cortex.The fcMRI technique might be a valuable approach to reveal the pathophysiological changes of nerve network caused by brain tumor.