Significant plain film findings in sigmoid volvulus.

The aim of this study was to evaluate the plain abdominal radiographs of patients thought clinically to have a sigmoid volvulus. Strict diagnostic criteria based on the findings at barium enema and/or surgery were applied to establish or refute a diagnosis of sigmoid volvulus. The presenting plain abdominal radiographs were assessed for 10 radiological signs considered valuable in the diagnosis of sigmoid volvulus. Of the 17 patients with a volvulus, 88% had 6 or more signs, and in the 5 patients without a volvulus, 80% had 4 signs or less. Five signs achieved significance in differentiating between the groups. Three signs, apex of the loop under the left hemi-diaphragm, inferior convergence on the left and the left flank overlap sign, were 100% specific as well as being highly sensitive. The signs which were least specific were a distended ahaustral sigmoid loop and an air fluid ratio greater than 2:1.