CT findings in five dogs with surgically confirmed colonic torsion.

Colonic torsion is a life-threatening condition that results in colonic ischemia, necrosis, perforation, sepsis, and eventual death. The aim of this multicenter, retrospective case series study was to describe the CT findings in dogs with surgically confirmed colonic torsion. Medical records were searched for dogs with surgically confirmed colonic torsion following abdominal CT. Five dogs met the inclusion criteria. Three had a history of chronic intermittent diarrhea prior to presentation. Two dogs presented with acute vomiting, diarrhea, and abdominal pain and one dog presented with acute vomiting and lethargy. Computed tomographic findings in all dogs with surgically confirmed colonic torsion include: "whirl sign," displacement and distension of the cecum and colon, focal narrowing of the colon, and distension of the mesenteric vasculature in all dogs (5/5); streaky peritoneal fat and peritoneal effusion (4/5), pneumatosis coli (2/5), small intestinal distension (2/5), portal vein thrombosis (1/5), and reduced colonic wall contrast enhancement (1/5). In all dogs (5/5), the torsion site was the descending colon and demonstrated an anticlockwise rotation. At surgery, three of the five dogs had a partial colonic torsion with hyperemia at the site of obstruction and two of the five dogs had a complete torsion with marked necrosis of the colonic wall. Displacement of the colon and cecum, segmental distension and focal narrowing of the colon, the presence of a "whirl sign" and distension of the mesenteric vasculature are CT findings highly suggestive of colonic torsion.