肠易激综合征患者脑部痛觉功能区域的变化

Alterations in focal encephalic function in patients of irritable bowel syndrome

目的应用血氧水平依赖性功能性磁共振(BOLD fMRI)技术研究肠易激综合征(irritablebowelsyndrome ,IBS)患者颅内痛觉功能区的变化及临床意义并比较与正常人的差异。方法2 0 0 2年1月～2 0 0 4年2月期间,参照罗马II诊断标准纳入67例肠易激综合征患者和10例正常志愿者,其中腹泻型肠易激综合征44例,男19例,女2 5例。年龄3 4～73岁,平均年龄5 3 0 7±8 44岁。便秘型肠易激综合征2 3例,其中男12例,女11例,年龄2 1～74岁,平均年龄46 2 2±14 64岁。直肠注气试验记录感觉阈值和感觉评分;功能性磁共振(fMRI)分析直肠扩张3 0ml、60ml、90ml和12 0ml时颅内痛觉功能区扣带前皮质(ACC)、脑岛皮质(IC)、额前皮质(PFC)及丘脑(THAL)的激活面积和强度。结果腹泻型IBS患者排便急迫和疼痛阈值显著低于便秘型患者和正常志愿者(P <0 0 5 ) ;腹泻型IBS患者在直肠注气90ml和12 0ml时视觉模拟评分(VAS)显著高于正常志愿者(P <0 0 5 ) ;便秘型IBS患者直肠扩张12 0ml时额前皮质、右侧丘脑兴奋面积较正常对照组显著增高(P <0 0 5 ) ,腹泻型IBS患者直肠扩张12 0ml时右侧脑岛皮质、额前皮质和右侧丘脑的兴奋面积较正常对照组显著增高(P <0 0 5 ) ;所有IBS患者直肠扩张90ml时脑岛皮质、直肠扩张12 0ml时脑岛皮质。

Objective To investigate the alteration and clinical significance of encephalic activated areas by using blood oxygenation dependent functional magnetic resonance imaging(BOLD-fMRI) in patients of irritable bowel syndrome^(IBS). Methods From January 2002 to February 2004,sixty-seven IBS patients including 44 cases of diarrhea predominant and 23 cases of constipation predominant, and 10 healthy volunteers were enrolled into study. Rectal balloon-distention stimuli were performed in all subjects. Rectal sensation and visual analogue scale(VAS)were recorded, activated area and activated intensity of focal encephalic functional area including ACC,PFC,THAL and IC were measured.Results The threshold of urgency and dyschizia in diarrhea predominant IBS(D-IBS) patients were significantly lower than that of constipation predominant IBS(C-IBS) patients and controls(P<0.05);VAS of D-IBS patients were much higher than that of controls when administrated 90ml and 120ml rectal balloon-distention(P<0.05);Activated encephalic area of prefrontal cortex(PFC) and right thalamus(R-THAL) in C-IBS patients was significantly increased when rectal balloon-distention up to 120ml(P<0.05) .Besides, activated area of insular cortex(IC), prefrontal cortex(PFC) and right thalamus(R-THAL) in D-IBS patients increased significantly when rectal balloon-distention up to 120ml(P<0.05);The alterative signal intensity of IC,PFC and THAL in all IBS patients was significantly higher than that of controls(P<0.05) when rectal balloon-distention up to 120ml,while only intensity of IC had significance when distention up to 90ml(P<0.05).Conclusions BOLD-fMRI has its clinical value in assessment of functional change of regional brain activation. The results of this study indicated that hypersusceptibility caused by rectal balloon-distention could be demonstrated by BOLD-fMRI in IBS patients and the region and intensity increased in IC, PFC and THAL,which may be the major functional areas involving visceral perception.