电针刺激合谷穴在颈脊髓内效应的功能磁共振成像的初步研究

An fMRI study on cervical spinal cord after acupuncture electrical stimulation at Hegu(LI4)

目的：观察比较穴位刺激与非穴位刺激的正常颈脊髓对针灸信号效应特征,初步探索脊髓针灸效应的作用机制,为探索针灸治疗脊髓损伤的作用机理提供一定的实验依据和方法。方法：16名健康志愿者按要求随机分成2组（每组8名）分别进行电刺右手合谷穴位和伪穴位,采用＂静息-任务刺激-静息＂的时段设计模式,共4次刺激,5次静息,各长35 s。获得的f MRI信号用AFNI软件进行后处理,得到激活信号与解剖信号的叠加图、激活信号值曲线。结果：神经功能激活区域大部分位于高位与低位颈脊髓平面,主要集中于C5~T1和C2~C3;5位志愿者在C2、C3、C5与C6平面脊髓前角出现神经功能激活;同时在C2、C5及C6平面对侧脊髓后角出现神经功能激活。电刺伪穴位组的脊髓f MRI激活结果：神经功能激活区域主要集中于C5~T1,高位颈脊髓未发现神经功能激活区;激活部位主要位于同侧脊髓后角。结论：利用单次激发快速自旋回波序列脊髓功能核磁共振技术能检测电刺合谷穴及其伪穴位时正常脊髓功能变化的信号,穴位刺激能引起更广泛的脊髓激活区域,高位脊髓激活区可能是针灸经络的特定激活区域;使用1.5T医用核磁共振机和常规颈线圈对脊髓损伤患者的脊髓功能核磁共振成像能检测到受损脊髓对电刺合谷穴时的神经信号,有助于评估脊髓功能状况。

Objective： To investigate the acupuncture response by evaluating the neuronal activity in cervical spinal cord assessed with SEEP-fMRI by comparison between electrical acupuncture stimulation at LI4 and the sham point. Methods： The fMRI data using single-shot fast spin-echo sequenee（SSFSE） with 42.4 ms echo time on a 1.ST MRI scanner（GE Clinical Sys- tem） were acquired in sixteen subjects with electro-acupuntcure at an acupoint and at a nearby ＂sham＂ point, and nine pa- tients with cervical spinal cord injury with electro-acupuntcure at LI4. Cervical spinal cord activation was measured both in the sagittal and transverse imaging planes. Postprocessing was performed by AFNI（Analysis of Functional Neuroimages） software system. Electrical LI4 without stimulation（rest） was applied in 35-s epochs alternating with 35-s epochs of stimulation. Images were acquired repeatedly during alternating rest and stimulation periods for five times, resulting in a total of 63 time points recorded with the ending of R5=35s. Results： Our results revealed that common activation areas in response to LI4 and sham point acupuncture measured in the spinal cord were most in terms of the ipsilateral posterior direction, and the localizations of the segmental fMRI activation were at C5 through TI. The activated regions localized to the ipsilateral side of lower cervical segments （C5 through T1） were in agreement with the neural anatomy. However, the activation of the upper cervical segment, in particular C2-C3 level, located at the ipsilateral posterior and anterior direction was only found at the real acapoint. These specific spinal cord activation patterns might suggest that stimulation of LI4 has a specific effect on spinal cord neuronal ac- tivity, absent with the sham-acupoint. Conclusion： The fMRI activations could be reliably detected with electro-acupuntcure at LI4 in the human spinal cord using SSFSE sequence. The anatomic location of neural activity correlated with the sensorimotor deficits. But the activation of the upper cervical segment, in particular C2-C3 level, might correspond to the special transmis- sion channel of acupuncture.