Intestinal malrotation as an incidental finding on CT in adults

Background.(I) Intestinal malrotation in adults is usually an incidental fi nding on computed tomography (CT), We present the CT findings of 18 adult p atients with malrotation and discuss the clinical implications. Methods: Abdominal scans of 18 patients (12 women, six men; age range = 15- 79 years) with intestinal malrotation were reviewed. Special attention was directed to the location of the superior mesenteric vessels, the location o f the small and large bowels, the size of the uncinate process, the situs d efinition, and additional anomalies. Results: The malrotation was an incidental finding in all but one patient. The malrotation was type Ia in 17 patients and IIc in the one symptomatic p atient. The superior mesenteric vessels were vertically oriented in 10, inv erted in two, normally positioned in four, and miller imaged in two cases w ith situs ambiguus. All patients had aplasia of the pancreatic uncinate pro cess, five had a short pancreas, and two had a preduodenal portal vein. Fou rteen patients had a normal situs and four had heterotaxia. Seven patients had polysplenia, six of which with associated inferior vena cava anomalies. Conclusions: Intestinal malrotation can be diagnosed on CT by the anatomic location of a right-sided small bowel, left-sided colon, an abnormal relati onship of the superior mesenteric vessels, and aplasia of the uncinate proc ess. Awareness of these abnormalities is necessary to diagnose this anomaly . It should be sought in patients with a situs problem, inferior vena cava anomalies, polysplenia, or preduodenal portal vein. Although usually an inc idental finding, it is important to diagnose such a malrotation because it may cause abdominal symptoms. Also, knowledge of associated vascular anomal ies is important when abdominal surgery is planned.