Presentation
Abdominal pain and distention.
Patient Data
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Medium to large amount of colon stool. Slight turning/narrowing of afferent distal descending colon with obstruction. This transitions into dilated, air-filled sigmoid colon with the classic "coffee bean" shape (see the scout). Rapid taper of dilated more distal sigmoid colon into a twisted segment. The volvulus is best appreciated on the coronal and axial images. Thickening of the rectum is likely due to vascular congestion.
Hiatus hernia.
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Arrows indicate the afferent loop (distal descending colon entering the volvulus) and the efferent loop (distal sigmoid colon twisting as it exits the volvulus).
Case Discussion
Classic case of sigmoid volvulus. The afferent loop of distal descending colon twists and narrows as it enters the volvulus without becoming completely obstructed, although some degree is likely present based on the amount of upstream stool. The efferent loop is clearly obstructed, resulting in massive distention of the sigmoid colon, forming the classic "coffee bean" sign. Thickening of the rectum is likely due to congestion as the superior rectal vessels are involved in the volvulus (IMA twists on the axial images).