[Ultrasonographic assessment of sigmoid colon in patients with irritable bowel syndrome].

UNLABELLED: Although the pathophysiological factors may play a role in the pathogenesis of irritable bowel syndrome (IBS), the function of sigmoid colon has been reported as a major pathogenesis of IBS. Our objective was to evaluate motility patterns of sigmoid colon by using ultrasonography(US) in patients with IBS compared to healthy volunteers (HV). SUBIECTS AND METHODS: <Fasting phase> US examination of sigmoid colon was performed in 69 patients with IBS and 69 HV with 3.75 MHz curved array scanner and 7.5 MHz linear array scanner. The US probe was positioned longitudinally to permit simultaneous visualization of sigmoid colon crossing over the iliopsoas. We classified 3 types of fasting sigmoid colon, spastic type, empty type, and normal type, according to the US findings. <Postprandial phase> Four IBS patients with diarrhea, 4 with constipation and 4 HV were given the liquid test meal (200ml, 400kcal). The frequency of segmental contractions (contractions without propagation) and propulsion were evaluated by US in the same fashion for 30 minutes before and for 60 minutes after investigation.

RESULTS: <Fasting phase> Sixty-two percent of IBS showed spastic type and 65% of HV showed normal type. IBS patients accounted for 80 % of spastic type (IBS vs spastic type of US findings: Sensitivity 62%, Specificity 91%). <Postprandial phase> The changes of frequency of segmental contractions were smaller in IBS patients with constipation. The changes of frequency of propulsion were larger in IBS patients with diarrhea.

CONCLUSION: Ultrasonographic assessment of sigmoid colon may provide a better understanding of the pathogenesis of IBS.