应用功能性磁共振成像技术研究大脑内便意感受相关区域的功能活动

Application of functional magnetic resonance imaging for exploring defecation feeling area in normal brains

目的应用功能性磁共振成像(functional magnetic resonance imaging,fMRI)技术探索正常儿童及成人大脑内便意感受相关区域的功能活动情况。方法自2017年2月至2018年7月,将四川大学华西医院小儿外科收治的符合纳入标准的无排便功能障碍的12例体表血管瘤患儿作为正常儿童组(儿童组),将招募的12例排便功能正常的青年志愿者作为正常成人组(成人组)。儿童组中,男7例,女5例;平均年龄为4.08岁,年龄范围为2~6岁;平均体重为17.1 kg,体重范围为12.8~25.0 kg。成人组的受试者均为男性,平均年龄为25.5岁,年龄范围为23~28岁;平均体重为64.25 kg,体重范围为58~76 kg。所有受试者均需先进行直肠肛门测压检查,记录引起受试者出现直肠内初始感觉以及急迫便意时的直肠内气囊充气量。随后使用fMRI技术观察所有受试者在直肠内初始感觉和急迫便意刺激下,其大脑内激活区域的分布情况并进行对比。结果在直肠内初始感觉的刺激下,所有受试者的大脑内均未出现与直肠扩张刺激相关的活动区域。在急迫便意刺激下,正常成人大脑内的额叶(包括额极区、额下回及额上回)、脑岛、小脑、扣带回及丘脑区域出现了激活,正常儿童大脑内的额上回、脑岛、小脑、扣带回(前部及后部)及丘脑区域也出现了激活。与儿童组的结果对比,在急迫便意刺激下,成人组大脑内的额极区、扣带回和小脑区域的活动强度要高于儿童组,而儿童组大脑内没有活动强度明显高于成人组的区域。结论正常人群大脑中的额叶(包括额极区、额上回及额下回)、脑岛、小脑、扣带回及丘脑区域可能是参与便意感受的重要区域;在类似的便意感受下,正常儿童大脑内的额极区、扣带回及小脑区域的活动强度要稍弱于正常成人。

Objective To employ functional magnetic resonance imaging(fMRI)to explore the functional activities of the relevant areas of defecation feeling in normal adults and children.Methods From February 2017 to July 2018,12 children with surface hemangioma without defecation dysfunction were included in normal children group.Then 12 young volunteers with normal bowel function were included as normal adult group.In children group,there were 7 boys and 5 girls with an average age of 4.08(2-6)years and an average weight of 17.1(12.8-25.0)kg.The subjects in adult group were all males with an average age of 25.5(23-28)years and an average weight of 64.25(58-76)kg.Anorectal manometry was performed and the volume difference of rectal balloon for evoking the first sensation in rectum and the urge desire to defecate were recorded.Then the changes of brain activity areas were evaluated by fMRI during rectal stimulation at the first sensation and the sensation of urge desire to defecate.Finally,the data were analyzed and compared.Results No regions were significantly activated during the first sensation of rectum stimulation in all subjects.Activation of frontal lobe(including frontal pole,inferior frontal gyrus&superior frontal gyrus),insular cortex,cerebellum,anterior cingulate gyrus and thalamus were observed during the sensation of urge desire to defecate in healthy adult group;activation of superior frontal gurus,insular,cerebellum,cingulate gyrus and thalamus were observed during the rectal balloon distention stimulation in healthy children group.The activity intensity of frontal lobe,cingulate gyrus and cerebellum in healthy adult group was higher than that in healthy children group while no activity of cerebral area was higher than that in healthy children group.Conclusions Frontal lobe(including frontal pole,inferior frontal gyrus&superior frontal gyrus),insula,cerebellum,cingulate gyrus and thalamus in human brain may be the relevant areas of defecation feeling.During similar defecation feeling,the activity intensity in frontal pole,cingulate gyrus and cerebellum in brain of normal children is weaker than that of normal adults.