Radiology of the laparoscopic Roux-en-Y gastric bypass procedure: conceptualization and precise interpretation of results.

Obesity is an epidemic in the United States. The laparoscopic Roux-en-Y gastric bypass procedure is an effective surgical intervention that can produce dramatic weight loss in morbidly obese patients. Despite the inherent risks, the surgery is increasing in popularity. Radiology plays a crucial role in postoperative evaluation. Upper gastrointestinal (UGI) series and abdominal computed tomography (CT) are the primary radiologic tools used in assessment of possible complications. With knowledge of the normal postoperative appearance, performance of UGI studies and interpretation of the results should be easy. The 24-hour postoperative examination allows reliable detection of anastomotic leaks. Although strictures of the gastrojejunal anastomosis are a common complication, they are often diagnosed and treated with endoscopy. In a thorough examination, one also evaluates for degraded pouch restriction, including a patulous gastrojejunal anastomosis or gastrogastric fistula, as a late cause of weight gain. Knowledge of the postoperative anatomy also assists in detection of internal hernias. CT is invaluable in detection and characterization of small bowel obstructions and internal hernias. CT may allow diagnosis of anastomotic leaks, abscesses, gastrogastric fistulas, and intra-abdominal hematomas. CT-guided percutaneous procedures, such as placement of gastrostomy tubes or drainage of fluid collections, can obviate emergency exploration and may be the only procedural intervention necessary for a cure.