直肠刺激的脑功能磁共振成像研究

目的：运用功能磁共振成像(fMRI)研究正常人和肠易激综合征(IBS)患者直肠刺激时脑内局部活动。方法：11名正常人和26例IBS患者为对象。以不同气体容量扩张直肠获得fMRI图像，并和T1W解剖图像融合，进行脑内活动区的面积和信号强度分析。结果：大多数正常人和IBS患者的直肠刺激明显激活扣带回前皮层(ACC)、脑岛皮层(IC)、前额叶皮层(PFC)和丘脑(THAL)。在正常人中，注气量达90ml和120ml时，均以ACC中的活动Ⅸ面积最大；在不同的注气量时，绝大多是以PFC和ACC中的活动区MR信号强度变化幅度最大。在相同容积直肠刺激时，IBS患者脑内活动区比正常人组活跃；IBS患者组在疼痛性直肠扩张时脑内活动区以PFC最为明显。结论：正常人直肠刺激时，中枢兴奋区主要位于ACC和PFC；而IBS患者在疼痛性直肠扩张时以PFC为主。

Brain studies in the irritable bowel syndrome patients using fMRI

Objective To study the regional brain activation in the healthy volunteers and irritable bowel syndrome (IBS) patients during the rectal distention stimulation. Methods Single shot GRE-EPI imaging was performed in 11 healthy volunteers and 26 IBS patients during various volume rectal balloon-distention. Functional magnetic resonance imaging (fMRI) were mixed with T1W anatomic images. The area and signal intensity of the brain activation regions were also analyzed. Results The rectal distention stimulation increased the activity of anterior cingulate contex (ACC), insular cortex (IC), prefrontal cortex (PFC) and thalamus (THAL) in most of the volunteers and the IBS patients. The area of activation region at ACC in volunteers was the biggest during 90 ml and 120 ml rectal balloon-distention. The changes of MR signal intensity were the greatest in the activation region at ACC and PFC during various balloon gas volume. The brain activation in the IBS patients was more significant than that of the volunteers during the same rectal balloon gas volume. The brain activation regions in the IBS patients were IC,PFC and THAL during the painful rectal distention stimulation. PFC was the most obvious region. Conclusions The central activation areas are ACC and PFC in the volunteers during the rectal distention stimulation. The brain activation region in the IBS patients is mainly PFC during the painful rectal distention stimulation.