1. Introduction
2. Case Presentation
A 26-year-old man with chronic constipation and occasional mild abdominal pain in left lower quadrant. Double-contrast barium enema images. A, Short segment narrowing at rectosigmoid junction (arrow) with twisting of mucosal folds (twisted ribbon sign) and redundant sigmoid colon. B, Gradual unwinding of the loop and opening of narrowed segment seen on air insufflation. C, Eventration of left hemidiaphragm with upward migration of splenic flexure.
Multi Detector Computed Tomography (MDCT) of abdomen with positive rectal contrast. A, Axial image shows short segment narrowing of the sigmoid colon (white arrow) at its junction with descending colon. B, Coronal and oblique image reveals twisting of sigmoid colon mesentery with beaking at site of volvulus (white arrow) and crowding of vessels. C, Redundant sigmoid colon (thin white arrow) reaching up to lower border of liver with abrupt narrowing of sigmoid colon at the site of partial volvulus (thick white arrow). D, Eventration of left hemidiaphragm and upwards migration of splenic flexure (thin white arrow) with convergence of vessels (black arrow) and abrupt narrowing (thick white arrow) at the site of twist.

