Sigmoid volvulus

Case contributed by Talal F M Abdullah
Diagnosis certain


Elderly patient complain of abdominal distension, constipation since a week. Presenting with increasing course of pain and bloating after alleged few bouts of diarrhea. CT requested to rule out bowel ischemia.

Patient Data

Age: 75 years
Gender: Male

Scout CT images show marked dilatation of the sigmoid giving it a coffee bean shape.  It extends superior to the transverse colon, the so called northern exposure sign.  Absent of gas in the rectum.


Rectal contrast tapers to the rectosigmoid junction, giving the appearance of the bird beak sign.

Swirling of the sigmoid mesentery noted, swirl sign.

Moderated dilatation of the sigmoid colon and fluid level noted.  It extends to the right upper quadrant abutting the liver, liver overlap sign.  Also extends superior to the level of transverse colon, northern exposure sign.  No abnormal wall enhancement or pneumatosis.

The proximal colon is loaded with stool, yet not dilated and no dilatation of small bowel (acute obstruction).

No vascular compromise.  No air in portal vein.

Few renal parenchymal cysts.  Few hypodense splenic lesions.

No free air.  Mild pelvic free fluid.

Case Discussion

This is a classical presentation of sigmoid volvulus and its associated radiological signs.  An attempt of fluoroscopic reduction failed and patient shifted to the operating theater.

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