Fig. 9

Sigmoid volvulus in a 75-year-old female patient presented with acute abdominal pain and distension. a Plain erect abdominal film showing distended sigmoid loop with inverted U configuration and coffee bean sign. b Post contrast axial CT image showing a proximal–superior sigmoid transition (white arrowheads). c Post contrast axial CT image showing distal–inferior sigmoid transition (red arrowheads), which is oriented in the direction opposite to the proximal transition. d Coronal CT reformatted image showing markedly dilated gas- and feces-filled sigmoid loop (white arrows) with loss of its haustral markings (yellow arrowheads) and extended from the pelvis way up to the left upper abdomen, giving an inverted U configuration, forming a closed-loop obstruction. e Coronal CT image showing twisting of the mesentery and mesenteric vessels of sigmoid colon, giving a whirl sign (circle)