肱二头肌不同模式运动任务刺激下的颈髓功能磁共振成像研究

Functional magnetic resonance imaging of the cervical spinal cord with the stimulation of different motor tasks completed by biceps brachii

目的探究肱二头肌不同模式运动任务刺激下的颈髓激活区分布及是否存在运动刺激一颈髓激活强度的同侧优势性。方法9例健康右利手受试者行双上肢的肱二头肌负荷任务和屈肘运动任务试验。采用GE1．5T磁共振系统运用GRE—EPI扫描序列行颈髓功能磁共振成像（fMRI），行BOLD图像分析，对激活区的信号强度变化进行统计学分析。结果（1）肱二头肌不同模式运动任务刺激下的颈髓激活区主要分布于C5～C6节段，邻近C7～C8节段亦出现少量激活；（2）单侧上肢运动条件下，脊髓双侧激活现象多见；（3）运动肢体同侧的脊髓激活区信号强度变化显著大于对侧（P〈0．05）。结论肱二头肌不同模式运动任务诱发颈髓激活的节段分布与主要收缩肌——肱二头肌的脊髓支配节段（C5、C6）相符合，存在运动刺激-颈髓激活强度的同侧优势性。

Objective To investigate the distribution of active pixels when different motor tasks were completed by different lateral upper limb （biceps brachii） and to determine whether there is the the motor task-dependent lateral activity ascendancy of cervical spinal cord. Methods Nine right-handed healthy volunteers received anatomical FRFSE T2WI and gradin-echo-echo-planer imaging functional magnetic resonance imaging（fMRI） with a 1.5T whole body MRI scanner （CE 1.5T Twin speed infinity with excite Ⅱ ）. The volunteers performed two different motor tasks, which were isometric weight bearing task and isometric elbow-flexlon, with their bilateral upper limbs. The fMRI data were processed by BOLD function package （Function 2.6.6i software package） on the Advantage Workstation. While the signal intensity changes of the ac, tive pixels were also analyzed by the SPSS software. Results （ 1 ） The concentrated active pixels of spinal cord were found at the spinal segment of C5-C6 under different motor innervations, with a few activity also appearing at the spinal segment of C7-C8. （ 2 ） Although the motor task was performed by single upper limb, spinal cord pixels were found on the bilateral sides of the spinal cord in most of all subjects. （3） The fMRI signal intensity change was significantly higher on the side of the cord ipsilateral to the moving upper limb than the contralateral （ P 〈 0.05 ）. Conclusions The location of spinal cord activation of the two motor tasks has an anatomic correspondence to the segment dominated by spinal cord of the biceps brachii, the main contractor. The motor task-dependent lateral activity ascendancy of cervical spinal cord can be observed.