abdominal ultrasonography barium enema CT scan of the abdomen endoscopic retrograde cholangiopancreatography endoscopic ultrasonography gastric bypass bariatric surgery gastrostomy G tube HIDA scan laparoscopy liver biopsy nasogastric intubation percutaneous transhepatic cholangiography serum bilirubin small bowel followthrough stool culture stool guaiac Hemoccult <a href=http://newisotretinoin.com/#covyxii>buy accutane</a> Int J Impot Res.They can vary in size and shape from as small as a grain of sand to as large as a golf ball DIGESTIVE SYSTEM Trocar A B FIGURE A Trocars in place for laparoscopic cholecystectomy.Mayer J.