Small-Bowel Complications of Major Gastrointestinal

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1 Small-owel Complications of Gastrointestinal Surgery Gastrointestinal Imaging Pictorial Essay Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved Kumaresan Sandrasegaran 1 Dean D. Maglinte 1 John C. Lappas 1 Thomas J. Howard 2 Sandrasegaran K, Maglinte DD, Lappas JC, Howard TJ Received June 4, 2004; accepted after revision December 8, Department of Radiology, Indiana University Medical Center, UH Suite 0279, 550 N. University oulevard, Indianapolis, IN ddress correspondence to K. Sandrasegaran (ksandras@iupui.edu). 2 Department of Surgery, Indiana University Medical Center, Indianapolis, IN. JR 2005; 185: X/05/ merican Roentgen Ray Society Small-owel Complications of Major Gastrointestinal Tract Surgery OJECTIVE. Gastrointestinal complications of major abdominal surgery often require radiologic assessment. The purpose of this article is to review the expected imaging findings and complications after commonly performed gastric and pancreatic surgery. CONCLUSION. It is important to understand the postsurgical anatomy to avoid misinterpreting an expected postoperative finding as a complication. Postoperative complications can be categorized as being related to adhesions, anastomosis, an enteric connection, and abnormal bowel position. bdominal, pancreatic, and gastric surgeons perform increasingly complex procedures. The radiologist is faced with CT or upper gastrointestinal contrast studies in which the anatomy is difficult to discern and there is uncertainty whether a finding is an expected postoperative change or relates to a complication. We retrospectively reviewed 377 cases of complex abdominal surgery performed by gastric and pancreatic surgeons at our affiliated institutions between January 2002 and ugust This pictorial essay shows the expected anatomy after commonly performed procedures and the range of complications that might be seen on imaging studies. For ease of categorization, postoperative small-bowel complications are classified as related to anastomosis, an enteric connection, abnormal bowel position, or adhesions. Whipple Procedure Whipple surgery is the only curative procedure for carcinoma of the head of pancreas (Fig. 1). The survival rate is approximately 30% 5 years after resection [1] and less than 1% for those who do not qualify for the procedure. It is important to appreciate postoperative anatomy to prevent overdiagnosing complications. There are several normally expected CT findings after the Whipple procedure. One is an afferent loop that is fluid filled and edematous and shows bright contrast enhancement in the first two postoperative weeks. This finding should not be mistaken for an ischemic or inflamed bowel or for fluid collection (Fig. 1). nother finding is reactive lymphadenopathy of up to 1.5 cm, which might be mistaken for a recurrent tumor [2]. This occurs in the first month after Whipple and other pancreatic surgery. Third is perivascular cuffing, which is commonly seen 1 2 months after surgery and should not be mistaken for recurrent tumor if preoperative scans did not show this finding. The celiac and superior mesenteric arteries are most affected and the common hepatic artery, less affected. Fluid collection in the duodenal bed in the first 3 weeks after surgery is an expected finding. Unless there are clinical signs of infection, these collections need not be drained; they tend to be transient. Pneumobilia is a permanent feature after hepaticojejunostomy. Periportal edema is seen in the first 2 postoperative weeks. Puestow Procedure In cases of severe chronic pancreatitis, end-to-end pancreaticojejunal anastomosis, such as in the Whipple procedure, is insufficient to drain the pancreas. The Puestow procedure (Fig. 2), a side-to-side longitudinal pancreaticojejunostomy, drains the pancreatic duct directly into a jejunum loop [3]. In Puestow s original description of the technique, the spleen and distal pancreas were removed. The Roux loop in the Puestow procedure may be mistaken for a peripancreatic fluid collection if the nature of surgery is not appreciated. JR:185, September

2 Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved ariatric Roux-en-Y Gastric ypass Procedure In the United States, more than 30% of adults are obese; 2 3% of men and 6 7% of women are morbidly obese [4, 5]. The Rouxen-Y gastric bypass procedure is the gold standard for bariatric surgery (Fig. 3). Open and laparoscopic Roux-en-Y bypass procedures are associated with a 5 20% incidence of complications [6]. n upper gastrointestinal contrast series is usually performed on the first postoperative day to detect gastrojejunal leak or obstruction. Understanding the postoperative anatomy is important to prevent overdiagnosis of complications (Fig. 4). Fig. 1 Whipple procedure., Diagram of anatomy after pylorus-preserving Whipple procedure in which cuff of duodenum is spared. Insert shows original Whipple procedure. The procedure entails radical dissection of pancreatic head, adjacent nodes, right half of omentum, gallbladder, common bile duct, and most or all of duodenum, followed by gastrojejunostomy/duodenojejunostomy, pancreaticojejunostomy, and hepaticojejunostomy. (Used with permission of Visual Media, Indianapolis, IN), Coronal reformat of isotropic source images in 64-year-old man 5 weeks after Whipple procedure shows edematous jejunal Roux loop (straight arrow). Compare with normal distal small bowel (curved arrow). Note normal-sized mesenteric nodes and stent at site of pancreaticojejunostomy (arrowhead). Complications nastomotic Complications nastomotic complications are the most significant bowel-related complications. They occur as a result of ischemia or suboptimal surgical technique, including staple gun failure, and account for most of the morbidity and mortality from the Whipple, Puestow, and Rouxen-Y procedures. nastomotic leak is found in up to 27% of patients having laparoscopic Roux-en-Y gastric bypass and, in our experience, it is the most common postoperative complication of the Puestow procedure. Stenosis Symptomatic anastomotic stenosis at the gastrojejunostomy site is found in approximately 3 5% of patients having Rouxen-Y gastric bypass surgery [7, 8]. The incidence is higher in patients having a laparoscopic Roux-en-Y bypass than in those having an open procedure. Upper gastrointestinal contrast series show delayed passage of contrast material. On CT, a spherical pouch or air contrast level is suggestive of this diagnosis. nother type of obstruction to gastric emptying is stenosis of the Roux limb at the site of mesocolonic tunneling in the Roux-en-Y bypass procedure. This is usually caused by excessive stapling at the site of the mesenteric defect. Ulcers nastomotic ulcers after gastric bypass procedures are common, with an incidence of 12 16% [9, 10]. n upper gastrointestinal double-contrast barium series may show these ulcers; however, the method is reported to have a sensitivity of only 50% compared with endoscopy [11]. In our experience, most stomal ulcers are visualized with modern fluoroscopic units and an adequate volume ( ml) of barium for oral contrast. Leak and perforation nastomotic leak or perforation is the most serious complication of Roux-en-Y gastric bypass surgery. It occurs in 3 5% of patients and is usually caused by staple gun failure. The incidence of leakage can be reduced by manually sewing the gastrojejunostomy [12, 13]. The complication is evident in the first postoperative week. lthough upper gastrointestinal studies may show this leak (Fig. 5), the images may be of poor quality because of the patient s size. It is our practice to obtain a CT scan with IV and positive oral (dilute water-soluble) contrast in any patient who has unexplained fever, pain, or persistent nausea. Some anastomotic leaks are complicated by an enteroenteric, enterovesical, or enterocutaneous fistula (Fig. 5). 672 JR:185, September 2005

3 Small-owel Complications of Gastrointestinal Surgery Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 2 Puestow procedure., Diagram of anatomy after modified Puestow procedure. The pancreas is filleted to expose main duct from neck to tail, and ductal calculi are removed. Roux loop of jejunum is anastomosed to capsule of pancreas with direct drainage of main and secondary pancreatic ducts into lumen of jejunum over 8 10 cm segment. This procedure is best performed if main pancreatic duct is significantly (>6 mm) dilated. (Used with permission of Visual Media, Indianapolis, IN), Magnified view of axial CT image at level of upper abdomen in 67-year-old woman shows drainage jejunostomy Roux loop (black arrowheads) containing gas bubbles closely applied to anterior aspect of atrophic calcified pancreatic body (white arrow). Fig. 3 Roux-en-Y gastric bypass procedure., Line diagram showing anatomy after Roux-en-Y gastric bypass procedure. In this procedure, 90% of stomach, entire duodenum, and proximal 30 cm of jejunum are excluded from digestion. Retrocolic version is demonstrated. Note short afferent loop at gastrojejunostomy, shown by circular staples. Duodenum is part of afferent loop at jejunojejunostomy, shown by linear sutures. (Used with permission of Visual Media, Indianapolis, IN), Upper gastrointestinal contrast image following Roux-en-Y gastric bypass procedure in 32-year-old woman shows esophagus (thin white arrow), gastric pouch (thick black arrow), short afferent loop (curved black arrow), and efferent loop (thick white arrows). Gastric remnant shows dilute contrast (curved white arrow) that has refluxed via duodenum from previous contrast study. (Fig. 3 continues on next page) JR:185, September

4 Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 3 (continued) Roux-en-Y gastric bypass procedure. C, xial CT image of upper abdomen performed without IV contrast after Roux-en-Y gastric bypass procedure in 36-year-old woman shows small gastric pouch filled with dense, orally introduced contrast (black arrow). djacent, but surgically separated, is most of stomach, gastric remnant (white arrow). Surgical staples separating the two are seen (arrowhead). Dilute oral contrast in remnant has refluxed via duodenum. This should not be mistaken for direct leak from pouch (gastrogastric fistula), which will manifest with dense oral contrast in remnant without any in distal duodenum. C Fig. 4 Roux-en-Y gastric bypass procedure anatomy. xial CT after the procedure in 48-year-old woman shows small pouch (straight white arrow) separated surgically from remnant (black arrow). Remnant was mistaken for abscess, and drainage catheter (curved arrow) was placed. Fig. 5 nastomotic leak in 29-year-old woman., Upper gastrointestinal contrast series after Roux-en-Y gastric bypass procedure shows edematous gastric pouch with leakage of contrast from gastrojejunal anastomotic site (black arrow) extending into left upper quadrant. There is also dense orally introduced contrast in gastric remnant (arrowhead) without contrast in the duodenum, indicating gastrogastric leak rather than retrograde reflux. Contrast is seen in transverse colon (white arrow) from previous upper gastrointestinal study., xial CT of upper abdomen after Roux-en-Y gastric bypass procedure shows leak at gastrojejunostomy site complicated by abscess (black arrow). n enterocutaneous fistula is shown by a track of gas bubbles (arrowheads). djacent images (not shown) indicate gas bubbles are in a fistula and not small bowel. Leaked oral contrast is seen in open abdominal wound (white arrow). fferent loop obstruction fferent loop obstruction occurs in 0.3% cases after gastroenterostomy [14], including illroth II surgery and the Whipple procedure. In illroth II surgery, the afferent limb is the duodenum; in pancreatic surgery, the Roux segment is the afferent limb (Fig. 1). Possible causes of obstruction are adhesions, internal hernia, anastomotic stenosis, stomal ulcer, recurrent tumor, and obturation from bezoar. Chronic partial afferent-loop obstruction is termed afferent loop syndrome. Diagnosis is possi- 674 JR:185, September 2005

5 Small-owel Complications of Gastrointestinal Surgery Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved ble but difficult to make with an upper gastrointestinal series (Fig. 6). CT is the most useful imaging technique for diagnosis. Enteric Connection Enteric-related complications are rare and result from improper anatomic connection of bowel loops. They are distinct from anastomosis-related complications. lind pouch syndrome Side-to-side anastomosis performed in Roux-en-Y gastric bypass surgery and after intestinal resection can result in an enlarged aperistaltic loop of the small bowel (Fig. 7). This enlarged loop is termed blind pouch. The blind pouches do C Fig. 6 fferent loop obstruction in 50-year-old man., Upper gastrointestinal contrast series after Whipple procedure shows dilation of afferent loop (white arrow) but not efferent loop (black arrow) or stomach (S). t surgery, the cause of the afferent-loop obstruction was found to be adhesions., xial CT image after Whipple procedure shows valvulae conniventes in uniformly dilated afferent loop (black arrows) confirming diagnosis of afferent-loop obstruction rather than pseudocyst. ack pressure from afferent-loop obstruction can cause biliary or main pancreatic duct dilation (not shown). C, Coronal multiplanar reconstruction shows distended afferent loop (black arrows) well. Presence of dilated fluid-filled structure with caliber of more than 3.5 cm in periportal region extending transversely anterior to spine is highly diagnostic. not form until approximately 4 months after surgery. These structures do not usually increase significantly in size after 12 months. lthough often an incidental finding, blind pouch can lead to malabsorption, gastrointestinal bleeding, and bowel perforation [15]. If symptoms are ascribed to the pouch, the pouch can be laparoscopically removed. Short gut syndrome Malabsorption can be caused by inadequate length of functioning small bowel after widespread smallbowel resection, such as in Crohn s disease. The minimal length of small bowel (excluding the duodenum) required to cope without parenteral nutrition or small-bowel transplantation is estimated to be 100 cm. Patients with a longer small bowel may also have digestive problems if the integrity of residual mucosa is impaired or the distal ileum has been resected. Short gut syndrome can be simulated by inadvertent surgery when the ileum is mistaken for the jejunum and a gastroileostomy rather than a gastrojejunostomy is created (Fig. 8). This complication is easily depicted by an upper gastrointestinal contrast series. CT examination may show multiple loops of nondistended jejunum that are not opacified with oral contrast, while there is oral contrast in the stomach, ileum, and right colon. JR:185, September

6 Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved ltered owel Position owel position is usually altered as a consequence of major abdominal surgery. However, small bowel may become trapped in undesirable positions postoperatively. This type of complication includes hernia and intussusceptions. Transmesenteric internal hernia Transmesenteric hernia can occur in any procedure, including liver transplantation and gastric bariatric surgery, in which a Roux loop is fashioned. Transmesenteric hernias are more common after laparoscopic bariatric surgery than after open surgery [16]. Transmesenteric hernias occur through the tear in the mesocolon through which the Roux loop is brought during a retrocolic anastomosis (Fig. 9). The reported incidence of internal hernia is about 2.5% [7, 16], and it generally involves the Roux loop. ntecolic placement of the Roux loop does not lead to transmesenteric hernia but is complicated by a Petersen-type internal hernia in rare cases. n upper gastrointestinal barium series could show the degree and location of smallbowel obstruction (Fig. 9) but is less useful in determining the cause of obstruction. The finding of dilated proximal jejunum that remains fixed in a high position on erect views suggests internal hernia. CT is more helpful in differentiating transmesenteric hernia (Fig. 10) from mesocolic tunnel stenosis, stenosis Fig. 7 lind pouch., Diagram of formation of blind pouch after side-to-side enteroenterostomy. Dotted black line shows anatomy before development of blind pouch. rrows show direction of peristalsis. The blind pouch is filled rather than emptied by peristalsis. (Used with permission of Visual Media, Indianapolis, IN) and C, xial CT images of mid abdomen 10 months after multiple enteric resections for gastrointestinal stromal tumor in 51-year-old woman show right (white arrows) and left (black straight arrow, C) blind pouches. These are adjacent to surgical clips (arrowheads). There is no obstruction of proximal or intervening small bowel (curved arrows). CT findings are fairly characteristic and should not be mistaken for abscess or small-bowel obstruction. S = stomach. at the jejunojejunostomy, or adhesion-related simple bowel obstruction. ppendix 1 shows findings that indicate transmesenteric hernia. There are no reports of a high frequency of other types of internal hernia after abdominal surgery. During diagnosis, it is important to distinguish an internal hernia from adhesive small-bowel obstruction. The former generally requires emergency surgery [17]. External hernia External hernias are another complication of gastrointestinal surgery. Ventral hernia is a major source of morbidity after any major abdominal procedure. It is more common after open Roux-en-Y gastric bypass surgery (incidence of up to 17%) than after a laparoscopic Roux-en-Y procedure. C 676 JR:185, September 2005

7 Small-owel Complications of Gastrointestinal Surgery Fig. 8 Short gut syndrome in 64-year-old man. Upper gastrointestinal contrast image shows only a few loops of small bowel between nasoenteric tube (white arrow) and ileocecal junction (black arrow). Patient had inadvertent gastroileostomy instead of gastrojejunostomy during illroth II surgery. C = ascending colon, DC = descending colon. Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 9 Transmesenteric hernia., Diagram of sagittal anatomy after Roux-en-Y gastric bypass procedure and potential site of transmesenteric hernia. (Used with permission of Visual Media, Indianapolis, IN), Upper gastrointestinal contrast image after Roux-en-Y gastric bypass procedure in 43-year-old woman shows distention of afferent (white arrow) and efferent (black arrow) with abrupt cutoff in mid efferent loop. ppearance is similar to mesocolic tunnel stenosis but more loops of distended efferent loops are seen, suggesting transmesenteric hernia, which was found at surgery. Richter hernia can occur at the site of the trocar after laparoscopic procedures [18]. Parastomal and lumbar are other external hernias commonly associated with abdominal surgery. Intussusception Intussusception accounts for 5% of small-bowel obstruction in adults [19] and is more common in postoperative patients. Possible causes include the presence of foreign material, such as sutures and feeding tubes, and hyperperistalsis of bowel that has been extensively handled [20]. CT appearances of these have been described [21]. JR:185, September

8 Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved dhesions dhesions are the most common cause of bowel obstruction after surgery. The adhesions can be symptomatic and nonobstructive. dhesive small-bowel obstruction is classified as simple, closed loop, or strangulating. Symptomatic, Without Overt Obstruction More than 90% of patients who have had abdominal surgery have enteric adhesions, even if there is no clinical obstruction [22]. We routinely find CT features that suggest adhesions in postoperative patients who report abdominal bloating or pain (Fig. 11) (ppendix 2). These patients do not have high-grade small-bowel obstruction but may have intermittent or low-grade small-bowel obstruction, for which CT has poor sensitivity [23]. dhesive Small-owel Obstruction The diagnosis of adhesion-related smallbowel obstruction is presumed on CT if there is a narrow zone of transition without an identifiable obstructive lesion. t our institution, low-grade and partial high-grade obstructions are treated by enteric decompression in which a long tube is placed under fluoroscopic guidance. lthough these patients rarely require surgery, those with complete, closed-loop, or strangulating obstruction require emergent surgery. CT findings of closed-loop (ppendix 3) and strangulating obstruction (ppendix 4) are shown in Figures 12 and 13, respectively [24, 25]. Summary In conclusion, knowledge of complex abdominal surgery is useful in differentiating postoperative anatomy from complications. When dealing with postoperative smallbowel obstruction, the radiologist should be able to diagnose less common types of obstruction, such as afferent-loop, closed-loop, and strangulating obstruction, as well as unusual causes such as internal hernia. This discrimination may be important in planning therapy because even high-grade partial adhesive obstructions are usually treated conservatively, while obstructions with an internal hernia or closed loop require surgery. References 1. Sohn T, Yeo CJ, Cameron JL, Koniaris L, Kaushal S, brams R. Resected adenocarcinoma of the pancreas 616 patients: results, outcomes, and prognostic indicators. J Gastrointest Surg 2000; 4: Mortele KJ, Lemmerling M, de Hemptinne, De Vos M, De ock G, Kunnen M. Postoperative findings following the Whipple procedure: determination of prevalence and morphologic abdominal CT features. Eur Radiol 2000; 10: Puestow C, Gillesby WJ. Retrograde surgical drainage of pancreas for chronic relapsing pancreatitis. M rch Surg 1958; 76: rolin RE. ariatric surgery and long-term control of morbid obesity. JM 2002; 288: Martin LF, Hunter SM, Lauve RM, O Leary JP. Severe obesity: expensive to society, frustrating to treat, but important to confront. South Med J 1995; 88: Cottam DR, Mattar SG, Schauer PR. Laparoscopic era of operations for morbid obesity. rch Surg 2003; 138: lachar, Federle MP, Pealer KM, Ikramuddin S, Schauer PR. Gastrointestinal complications of laparoscopic Roux-en-Y gastric bypass surgery: clinical and imaging findings. Radiology 2002; 223: Higa KD, oone K, Ho T, Davies OG. Laparoscopic Roux-en-Y gastric bypass for morbid obesity: technique and preliminary results of our first 400 patients. rch Surg 2000; 135: ; discussion, MacLean LD, Rhode M, Nohr C, Katz S, McLean P. Stomal ulcer after gastric bypass. J m Coll Surg 1997; 185:1 7; comment, Sanyal J, Sugerman HJ, Kellum JM, Engle KM, Wolfe L. Stomal complications of gastric bypass: incidence and outcome of therapy. m J Gastroenterol 1992; 87: Ott DJ, Munitz H, Gelfand DW, Lane TG, Wu WC. The sensitivity of radiography of the postoperative stomach. Radiology 1982; 144: Higa KD, oone K, Ho T. Complications of the laparoscopic Roux-en-Y gastric bypass: 1,040 patients what have we learned? Obes Surg 2000; 10: Schauer PR, Ikramuddin S, Gourash W, Ramanathan R, Luketich J. Outcomes after laparoscopic Roux-en-Y gastric bypass for morbid obesity. nn Surg 2000; 232: Jordan GL Jr. Surgical management of postgastrectomy problems. rch Surg 1971; 102: Maglinte DD. lind pouch syndrome: a cause of gastrointestinal bleeding. Radiology 1979; 132: Higa KD, Ho T, oone K. Internal hernias after laparoscopic Roux-en-Y gastric bypass: incidence, treatment and prevention. Obes Surg 2003; 13: Sandrasegaran K, Maglinte DD, Howard TJ, Kelvin FM, Lappas JC. The multifaceted role of radiology in small bowel obstruction. Semin Ultrasound CT MR 2003; 24: Matthews D, Heniford T, Sing RF. Preperitoneal Richter hernia after a laparoscopic gastric bypass. Surg Laparosc Endosc Percutan Tech 2001; 11: Reijnen H, Joosten HJ, de oer HH. Diagnosis and treatment of adult intussusception. m J Surg 1989; 158: llbery SM, Swischuk LE, John SD, ngel C. Postoperative intussusception: often an elusive diagnosis. (letter) Pediatr Radiol 1998; 28: Merine D, Fishman EK, Jones, Siegelman SS. Enteroenteric intussusception: CT findings in nine patients. JR 1987; 148: Menzies D, Ellis H. Intestinal obstruction from adhesions how big is the problem? nn R Coll Surg Engl 1990; 72: Maglinte DD, Kelvin FM, Rowe MG, ender GN, Rouch DM. Small-bowel obstruction: optimizing radiologic investigation and nonsurgical management. Radiology 2001; 218: althazar EJ, auman JS, Megibow J. CT diagnosis of closed loop obstruction. J Comput ssist Tomogr 1985; 9: althazar EJ, irnbaum, Megibow J, Gordon R, Whelan C, Hulnick DH. 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9 Small-owel Complications of Gastrointestinal Surgery PPENDIX 1: CT Findings of Transmesenteric Hernia (Fig. 10) Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved Cluster of dilated loops of bowel anterior to stomach or transverse colon Deviation, crowding, or engorgement of mesenteric vessels as they pass between stomach and transverse colon Downward displacement of transverse colon or hepatic flexure Close proximity of distal obstructed loop to site of mesenteric vessel abnormalities Fluid distention of obstructed loop with paucity of air Fig. 10 Transmesenteric hernia in 47-year-old woman. and, xial CT images show dilated jejunal loops anteriorly (large white arrows). Mesenteric vessels supplying these loops curve (small black arrows, ) through transverse mesocolon (small white arrows). Transition is abrupt (arrowhead), in line with slightly thickened mesocolon and proximal to site of jejunojejunostomy, shown by surgical clips (large black arrow). C, Coronal reconstruction in same patient shows distended efferent loops (black arrow) lying above and depressing transverse colon (white arrow). C JR:185, September

10 PPENDIX 2: CT Findings Suggesting Presence of dhesions (Fig. 11) Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved cute angulation of small-bowel loops Traction deformities Stretching of loops; air trapped in valvulae conniventes symmetric thickening of small-bowel wall Small-bowel loops closely applied to anterior peritoneum Thickening of anterior peritoneum Fig. 11 Nonobstructive symptomatic adhesions. xial CT image in 59-year-old man with abdominal pain after renal transplant shows small bowel adherent to anterior peritoneum (white arrows) and kinking of bowel loop (arrowhead). There were no overt CT features of small-bowel obstruction. Patient subsequently underwent adhesion lysis with improvement of symptoms. K = superior pole of transplanted kidney. PPENDIX 3: CT Findings of Closed-Loop Obstruction (Fig. 12) Distended fluid-filled loops C or U segment if axial CLO Radial distribution of loops in more oblique CLO Two ends of distended loop come together Proximal bowel less distended than closed loop Distal bowel nondistended Note CLO = closed-loop obstruction. Fig. 12 Closed-loop obstruction in 50-year-old man. and, xial CT images show beaked appearance of distal and proximal ends of closed loop (arrowheads) as well as bowel wall thickening and increased enhancement, indicating impaired mesenteric venous return. Fluid-filled, distended small-bowel loops (white arrows, ) show radial distribution. lack arrow () = jejunum. (Fig. 12 continues on next page) 680 JR:185, September 2005

11 Small-owel Complications of Gastrointestinal Surgery Downloaded from by on 12/22/17 from IP address Copyright RRS. For personal use only; all rights reserved PPENDIX 4: CT Findings in Strangulated Obstruction of Small owel (Fig. 13) Early Signs Wall thickening scites Mesenteric vessel engorgement Target or halo appearance due to submucosal edema C D Fig. 12 (continued) Closed loop obstruction in 50-year-old man. C, Sagittal reconstruction allows better appreciation of proximity of ends of closed loop (arrowheads). D, Coronal reconstruction shows radial pattern of closed loop (white arrows). Distended bowel in left flank containing oral contrast on images and D (black arrows) is jejunum, which lies proximal to closed loop. There is moderate ascites. dvanced Ischemia Mesenteric vessel blurring Hemorrhagic ascites Mesenteric or portal venous gas Pneumatosis Enhancement of bowel wall on venous phase of IV contrast Reduced enhancement of bowel wall on arterial phase of IV contrast Fig. 13 Strangulating obstruction., xial CT after Whipple procedure in 68-year-old woman shows enhancing loop of jejunum in left flank (white arrows). Patient was found to have necrotic jejunum with closed-loop obstruction at surgery, which was performed 8 hours later., xial CT in 63-year-old man 10 days after sigmoid colectomy shows mesenteric venous air (arrowheads). Patient died during emergency laparotomy and was found to have strangulating obstruction. JR:185, September