CT Findings in
Benign and Malignant Afferent Loop Syndrome

Keimyung Medical Journal 1998;17(2):266-275.

CT Findings in Benign and Malignant Afferent Loop Syndrome

수입계제 증후군: 전산화단층촬영에 의한 양악성의 감별진단

김홍; 김정식

Abstract

We evaluated retrospectively the CT findings of 17 patients in whom ALS was diagnosed surgically; clinically and radiologically. A subtotal gastrectomy with Billroth H anastomosis was done in 10 patients; a total gastrectomy with Roux-en-Y esophagoje-junostomy in five; a bypass gastrojejunostomy in one and a cholecystectomy with Roux-en-Y choledochojejunostomy in one. The 17 cases of ALS were as follows; five benign causes included internal hernia (n=2); marginal ulcer (n=l); kinking of the anastomosis site (n=l) and a unknown cause; and 12 malignant causes included recurrent stomach cancer (n=ll) and the progression of stomach cancer after a bypass gastrojejunostomy. The interval between the initial operation and the diagnosis of ALS was from 10 to 21 days in the three benign cases; and from 3 to 16 months in the 10 malignant cases. The A-loop was 42 mm in mean diameter in all the benign and malignant cases. The A-loop was evenly dilated without focal wall thickening in all five benign cases and three of the malignant cases; but unevenly dilated with irregular focal thickening of the distal duodenum and duodenojejunal junction in 9 malignant cases. CT could depict the causes of ALS in 15 cases (88%). Other associated CT findings were: in the benign cases; moderate dilation of the bile ducts (n=l); the internal hernia (n=2); and subhepatic abscess (n=l); and in the malignant cases; carcinomatosis peritonei (n=ll); distended gallbladder with wall thickening (n=6); dilation of the bile ducts (n=7); hydronephrosis (n=2); adrenal metastasis (n=l); and retroperitoneal lymphadenopathy (n=l). In conclusion; the benign ALS cases had even dilation of the A-loop without focal wall thickening; and a short interval between the initial operation and the diagnosis of ALS. But the malignant ALS cases had uneven dilation of the A-loop with focal irregular wall thickening of the distal duodenum and the duodenojejunal junction; carcinomatosis peritonei; and obstructive jaundice.

Key Words: Duodenum, afferent loop syndrome, Gastrointestinal tract, obstruction, Afferent loop, recurrent carcinoma, Duodenum