Normative Measures of Colon Length in Children With Inflammatory Bowel Disease, Aged 11–17 Years, Based on MRI

ABSTRACT

To better understand (abnormal) colonic anatomy on imaging, data on normal colonic anatomy in the unaffected population are crucial. We assessed colon lengths in children without constipation on MRI. This retrospective study included patients (< 18 years), who underwent MRI‐enterography between 2016 and 2020 for suspected inflammatory bowel disease, and did not meet Rome‐IV criteria for functional constipation. Patients with colonic inflammation were excluded. Primary outcome was the mean total colon length/BSA (cm/m ² ) (95% CI; ±2SD), and the secondary outcomes were total colon length (cm), rectosigmoid length/BSA (cm/m ² ), and rectosigmoid length (cm). Colon segments were independently measured on coronal T2‐weighted MRI using 3D multiple‐point measurements. Linear regression was used to evaluate associations between total colon length and sex, age, height, weight, body surface area (BSA). Eighty‐one patients (median age 15 years; range 11–17; 53% male) were included. The mean total colon length/BSA was 72.9 ± 21.0 cm/m ² . Mean total colon length was 115.8 ± 13.8 cm, mean rectosigmoid length/BSA was 24.2 ± 12.3 cm/m ² , and mean rectosigmoid length was 38.2 ± 7.9 cm. Additionally, we assessed colonic segments per age group. Colon length significantly correlated with age ( p  = 0.03), height ( p  < 0.001), weight ( p  < 0.001), and BSA ( p  < 0.001). In a multivariable linear regression analysis, BSA was significantly correlated with total colon length (95% CI 21.4–49.4; p  < 0.0001). This study provides data on colon and rectosigmoid lengths in children, aged 11–17 years, without constipation measured on MRI‐enterography. This knowledge can be used for the identification of abnormal colonic anatomy in children with therapy‐resistant constipation on imaging.