重复经颅磁刺激对正常人脑血流灌注和速度的影响

Influence of repetitive transcranial magnetic stimulation on cerebral blood flow perfusion and velocity in healthy people

目的:观察单光子发射计算机断层脑血流灌注显像及经颅多普勒仪观察重复经颅磁刺激前后正常人脑局部血流灌注量及血流速度的变化。方法:于2003-05/09对体检健康、自愿参加本实验的川北医学院12名受试者的左额叶给予20Hz,100%声强阈值磁刺激,连续100次刺激为一串,每串刺激间隔2min,共5串,并在刺激前后用单光子发射型计算机断层仪观察局部脑血流量变化及经颅多普勒超声仪测定脑动脉血流速度。结果:12名受试者均进入结果分析。①正常人重复经颅磁刺激后局部脑血流量与刺激前比较表现:左侧额叶皮质重复经颅磁刺激刺激前局部脑血流量减低2名,刺激后减低7名(χ2=3.87,P<0.05);刺激前未见异常,刺激后局部脑血流量增加6名(χ2=3.51,P<0.05);右侧额叶和双侧颞叶、枕叶刺激前正常,刺激后局部脑血流量表现为减低为主2名,增加为主3名,其余未见明显异常。②刺激后平均血流速度除左右大脑后动脉及椎动脉外,均有不同程度的增加,以左侧大脑前动脉及左侧大脑中动脉平均血流速度的增加尤为明显[(60.3±8.4),(87.7±11.2)m/s;(77.1±6.5),(90.5±14.6)m/s,P均<0.05]。③刺激过程中无明显不适。结论:给予健康人左额叶20Hz的重复经颅磁刺激(共500次),在短时间内能增快脑血流速度,但高频磁刺激对脑组织代谢及血流灌注的影响是复杂的。

AIM： To observe the cerebral blood flow perfusion imaging of single-photon computed tomography （SPECT） and the changes of cerebral blood flow perfusion and velocity before and after repetitive transcranial magnetic stimulation （rTMS） in normal subjects. METHODS： Between May and September 2003, 12 healthy physical examinees in North Sichuan Medical College were voluntarily treated with rTMS of 20 Hz and with the sound intensity liminal value of 100% at left frontal lobe, continuous 100 stimulations as a string, and 5 strings of stimulations were given with an interval of 2 minutes. Their changes of regional cerebral blood flow were observed under SPECT, and the cerebral arterial blood flow velocity was detected with transcranial Doppler ultrasonography before and after rTMS. RESULTS： All the 12 subjects were involved in the analysis of results. ① Comparison of regional cerebral blood flow in normal subjects before and after rTMS： The regional cerebral blood flow was reduced in 2 cases before the rTMS at left frontal lobe, and in 7 cases after rTMS （x^2=3.87, P〈0.05）; No abnormality was observed before stimulation, and increased in 6 cases after rTMS （x^2=3.51, P〈 0.05）. Before rTMS, it was normal in right frontal lobe, bilateral temporal lobes and occipital lobes, but mainly reduced in 2 cases and increased in 3 cases after rTMS, and no obvious abnormalities were observed in others. ② Except left and right posterior cerebral arteries and vertebral arteries, the average blood flow velocity was increased differently after rTMS, which was more obviously in left anterior cerebral artery and left middie cerebral artery [（60.3±8.4）, （87.7±11.2） m/s; （77.1±6.5）, （90.5±14.6） m/s, P〈0.05] . ③ There was no obvious uncomfortable sensation during stimulation. CONCLUSION： The rTMS of 20 Hz at left frontal lobe for 500 times can speed up the cerebral blood flow velocity of healthy subjects in a short time, but high frequency magnetic stimulation has complicate influence on the metabolism of brain tissue and blood flow perfusion.