Bouchoucha Michel, Devroede Ghislain, Bon Cyriaque, Raynaud Jean-Jacques, Bejou Bakhtiar, Benamouzig Robert
, Université Paris V René Descartes 15, Rue de l'Ecole de Médecine, 75270, Paris Cedex 06, France.
Hôpital Avicenne. Service de Gastroentérologie, 125, Rue de Stalingrad, 93009, Bobigny Cedex, France.
Int J Colorectal Dis. 2015 Oct;30(10):1381-9. doi: 10.1007/s00384-015-2277-8. Epub 2015 Jun 11.
Measuring colonic transit time with radiopaque markers is simple, inexpensive, and very useful in constipated patients. Yet, the algorithm used to identify colonic segments is subjective, rather than founded on prior experimentation. The aim of the present study is to describe a rational way to determine the colonic partition in the measurement of colonic transit time.
Colonic transit time was measured in seven segments: ascending colon, hepatic flexure, right and left transverse colon, splenic flexure, descending colon, and rectosigmoid in 852 patients with functional bowel and anorectal disorders. An unsupervised algorithm for modeling Gaussian mixtures served to estimate the number of subgroups from this oversegmented colonic transit time. After that, we performed a k-means clustering that separated the observations into homogenous groups of patients according to their oversegmented colonic transit time.
The Gaussian mixture followed by the k-means clustering defined 4 populations of patients: "normal and fast transit" (n = 548) and three groups of patients with delayed colonic transit time "right delay" (n = 82) in which transit is delayed in the right part of the colon, "left delay" (n = 87) with transit delayed in the left part of colon and "outlet constipation" (n = 135) for patients with transit delayed in the terminal intestine. Only 3.7 % of patients were "erroneously" classified in the 4 groups recognized by clustering.
This unsupervised analysis of segmental colonic transit time shows that the classical division of the colon and the rectum into three segments is sufficient to characterize delayed segmental colonic transit time.
使用不透X线标志物测量结肠传输时间简单、经济，对便秘患者非常有用。然而，用于识别结肠段的算法是主观的，而非基于先前的实验。本研究的目的是描述一种在测量结肠传输时间时确定结肠分区的合理方法。
对852例功能性肠和肛肠疾病患者的七个结肠段（升结肠、肝曲、右半和左半横结肠、脾曲、降结肠以及直肠乙状结肠）的结肠传输时间进行测量。一种用于高斯混合建模的无监督算法用于从这个过度细分的结肠传输时间中估计亚组数量。之后，我们进行了k均值聚类，根据过度细分的结肠传输时间将观察对象分为同质的患者组。
高斯混合模型后接k均值聚类定义了4类患者群体：“正常和快速传输”（n = 548）以及三组结肠传输时间延迟的患者，“右侧延迟”（n = 82），即结肠右侧传输延迟；“左侧延迟”（n = 87），即结肠左侧传输延迟；“出口性便秘”（n = 135），即终末肠道传输延迟的患者。在聚类识别出的4组中，只有3.7%的患者被“错误地”分类。
这种对结肠段传输时间的无监督分析表明，将结肠和直肠经典地分为三段足以表征结肠段传输时间延迟。
