Utility of Computed Tomography for Evaluation of Normal Small Bowel Rotation in Children Less than 2 Years of Age

Background: Traditionally, the fluoroscopic upper gastrointestinal (UGI) exam with either barium or water-soluble contrast has been used to assess potential small bowel malrotation in children. Computed tomography (CT) has not generally been used to assess malrotation in children. Objective: We investigated whether CT could potentially be used to evaluate the position and course of the normal duodenum in infants and very young children. Materials & Methods: A retrospective review was performed of children ages 0 - 2 who underwent a CT of the abdomen and pelvis. Patients with known altered anatomy were excluded. Demographic data of patients, including age, gender, ethnicity, and body mass index (BMI), were collected from the electronic health record. CTs were reviewed by board-certified and subspecialty-trained pediatric radiologists to assess if the normal course and position of the duodenum could be determined on CT. Confidence in visualization was recorded on a modified Likert scale (1 = not confident, 2 = somewhat confident, 3 = moderately confident, 4 = very confident). Inter-reader reliability was also assessed. A linear mixed regression model was used to predict confidence in visualizing the course of the duodenum. Results: A total of 202 CT scans in 155 unique patients were included. The duodenal course could be seen in 86% (95% CI: 80% - 90%) of cases. The mean ± SD confidence score in visualizing the course of the duodenum was 3.2 ± 1.1 (median 4/4, representing 53% of cases). IV contrast improved confidence by 0.47 points (SE 0.16). A collapsed duodenum was the most common limiting factor identified (30% of cases), reducing confidence by 1.54 (0.14; all p < 0.01). Inter-rater agreement for confidence in identifying the course of the duodenum, measured on a 1 - 4 Likert scale, was 0.52 (95% CI: 0.33 - 0.72), using a two-way random effects, single unit type intra-class correlation coefficient (p < 0.01). Conclusion: The course of the normal duodenum can be seen in a high percentage of CT exams in very young children with a moderately high confidence level. The most important factor for increasing confidence in identifying the duodenal course was the use of IV contrast; the most limiting factor was underdistension of the duodenum.