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E1152. Non-Rotation and Malrotation: A Case-Based Imaging Review with Surgical Correlation
Authors
  1. Maria Montano; Bryn Mawr Hospital, Main Line Health
  2. Anna Spivak; Bryn Mawr Hospital, Main Line Health
  3. Emily Kunkel; Bryn Mawr Hospital, Main Line Health
  4. Ani Pahlawanian; Bryn Mawr Hospital, Main Line Health
  5. Andre Pitt; Bryn Mawr Hospital, Main Line Health
  6. Nachum Stollman; Bryn Mawr Hospital, Main Line Health
Background
Congenital anomalies involving the intestines occur during the 6th to 10/12th weeks of embryologic development due to an arrest or disruption of normal dynamic counterclockwise gut rotation about the axis of the omphalomesenteric vessels. At the completion of expected gut rotation, normal anatomic positioning includes the superior mesenteric artery (SMA) to the left of the superior mesenteric vein (SMV) and the duodenum posterior to the SMA. The last portion of the intestinal tract to complete its rotation is the cecum with normal descent into the right lower quadrant (RLQ). After rotation is complete, peritoneal bands fix the bowel in place. Congenital anomalies involve a spectrum of rotation and fixation abnormalities that occur during different stages of development. Malrotation is associated with complications including volvulus, obstruction, and internal hernias.

Educational Goals / Teaching Points
The majority of the radiology literature focuses on malrotation in the pediatric population in the setting of volvulus. Symptoms of malrotation are dependent on the age of presentation. For example, in early infancy, symptoms tend to be generalized including vomiting (often bilious), abdominal pain and distention. Case reports of malrotation in the adult population are rare. The vast majority of malrotation is detected incidentally and is not the cause of the patient’s presenting reason for imaging workup. In cases with symptomatic intestinal malrotation, the most common presenting symptom is intermittent postprandial vomiting and abdominal pain. Since the clinical presentation is variable in adults, the diagnosis of intestinal malrotation may be delayed. Increased understanding of imaging findings in adult malrotation may lead to a higher index of suspicion, quicker diagnosis, and prompt operative intervention.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Investigation of presenting abdominal symptoms can be performed with multiple imaging studies to further elucidate the underlying etiology. Imaging options include radiographs, barium upper GI series and enemas, ultrasound, and CT. Currently, the diagnosis of non/mal-rotation is based primarily on radiographic signs such as bowel position in relationship to the ligament of Treitz, course of the duodenum, positioning of the cecum/appendix, and the SMA/SMV orientation. Two anatomic markers, Ladd bands and a narrow mesenteric base, predispose patients to increased complications, such as intestinal obstruction, volvulus, and internal hernias.

Conclusion
This educational exhibit presents multiple cases of nonrotation and malrotation and explores the clinical presentations, imaging workup, differential diagnosis, and important radiographic features for diagnosis. In addition, this exhibit reviews how abnormal anatomic radiographic relationships might be utilized to infer or predict the presence of Ladd bands and how this impacts surgical planning.