Purpose or Case Report: Upper gastrointestinal studies are used for the diagnosis of intestinal malrotation, and the configuration of the duodenum and position of the DJ flexure are used for diagnosis. There are various challenges associated with diagnosing malrotation on the AP view, and obtaining a lateral view is recommended for diagnosis. To be useful, the lateral view must be of adequate quality. In addition, radiologists must be aware of the normal appearance and configuration of duodenal variants such as duodenum redundum, on the lateral view, as misdiagnosis of these may lead to unnecessary surgery. We aim to determine the proportion of lateral views considered of adequate quality for diagnosis, as well as the prevalence of a not previously described sign, the 'descending stair' and its correspondence to a diagnosis of duodenum redundum.
Methods & Materials: Retrospective review of 100 UGI fluoroscopy exams of patients aged≤18 years between January and December 2018 was performed by a pediatric radiologist. The lateral view images/cine loops were reviewed independently first, and then the AP view. Only studies designated to have an adequate lateral view were evaluated for configuration of the duodenum and recorded as normal, abnormal or normal variant. In addition, the presence of a descending stair-step configuration was correlated with an AP view for a diagnosis of duodenum redundum.
Results: 26/100(26%) UGI exams were designated as having an adequate lateral view (M:16; F:10) with age range of 0 to 16 years. Of the adequate lateral UGI exams, 18/26(69%) were reported as normal, 7/26(27%) were reported as having a descending staircase variant and 1/26(4%) was reported as abnormal. Of the 7 descending stair duodenums 6/26(23%) were confirmed as having redundum duodenum on the AP view and 1 was reported as normal. The single abnormal lateral duodenum was confirmed on AP as a non-rotation.
Conclusions: Only 26% of UGI studies had recorded adequate lateral views for interpretation. In these, 23% had a descending staircase sign that corresponded to a diagnosis of duodenum redundum on the AP view. Radiologists should be aware of variant duodenum configurations including the descending staircase sign, to avoid misdiagnosis and unnecessary surgery. The lateral view of the duodenum is usually obtained during the UGIS by the right-side-down position for propelling contrast, but requires rapid patient repositioning for the frontal view which may account for the low frequency of diagnostic lateral views available for review.