Radiographic Pattern of Colon Transit Time in Iranian Children with Constipation

Background Studies on colonic motor function in pediatric patients with constipation have revealed some dysfunctional patterns of colonic transit. The aim of this study was to evaluate the times and patterns of colon transit time to diagnose and categorize of colon abnormalities. Materials and Methods: This descriptive, cross-sectional study was performed at Dr. Sheikh Pediatrics Hospital of Mashhad University of Medical Sciences, Mashhad, Iran during 2013-2019. Sixty-four children with chronic constipation that were referred to the radiology department were enrolled in the study. Segmental and total colon transit times (CTT) were calculated by using plastic markers and Metcalf Protocol. Data were analyzed using SPSS software (version 22.0). Results: Among 64 children with constipation (aged between 2 and 18 years), about half (51.5%) of patients had normal segmental and total CTT. Of 43 patients with a normal total CTT, 10 (23%) had a prolonged segmental CTT. the normal upper limits of CTT were considered for the right colon, left colon, rectosigmoid, and total colon at 20, 20, 30, and 60 hours, respectively. These times had a 97% specificity with AUC = 0.74 to 0.93 to differentiate the normal from the abnormal transit time. The transit abnormalities were included rectosigmoid retention (22%), colon inertia (17.2%), left colon retention (6.2%), and right colon retention (3.1%). Conclusion Both segmental and total CCT were found normal in half of our constipated patients and Rectosigmoid retention and colon inertia were the most common abnormalities. The normal upper limits for colon transit time in the northeast of Iran were less than those found in Western countries.