CT and MRI Features of Ileostomies

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1 Gastrointestinal Imaging Pictorial Essay El Mouhadi et al. Imaging Features of Ileostomies Gastrointestinal Imaging Pictorial Essay Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved Sanaâ El Mouhadi 1 Chaouki Tourabi Julien Cazejust Louisa zizi Yves Menu Lionel rrivé El Mouhadi S, Tourabi C, Cazejust J, zizi L, Menu Y, rrivé L Keywords: abdominal surgery, complications, CT, ileostomy, MRI DOI: /JR Received May 4, 2010; accepted after revision July 29, ll authors: Department of Radiology, Saint-ntoine Hospital, 184 Rue du Faubourg Saint-ntoine, Paris 75012, France. ddress correspondence to L. rrivé (lionel.arrive@sat.aphp.fr). JR 2011; 196: X/11/ merican Roentgen Ray Society CT and MRI Features of Ileostomies OJECTIVE. The purpose of this article is to describe CT and MRI features of normal anatomy, variants, and pathologic conditions of different ileostomies. CONCLUSION. Multiplanar imaging techniques are useful to identify the complications related to stoma construction and preexisting disease. Understanding the indications for ileostomy construction, surgical techniques, and postoperative anatomy is important for differentiating normal and abnormal imaging features. I leostomy is a frequently performed surgical procedure in which a loop of the distal small intestine is attached and opened through the abdominal wall to bypass the large intestine [1]. Current indications for ileostomy creation include relief of distal obstruction, protection of distal anastomoses, and temporary or definitive diversion of the fecal stream [2]. Construction of an ileostomy may lead to complications, some of which are related to recurrence of preexisting disease, whereas others are related to stoma construction [3 5]. Moreover, some normal variants can have clinical or radiologic features that mimic pathologic conditions. The purpose of this article is to describe the CT and MR features of normal ileostomies, variants, and complications. Types of Ileostomies Permanent end ileostomies are performed after proctocolectomy for inflammatory bowel disease or familial polyposis, if a reservoir is not chosen (Fig. 1). loop ileostomy is used to divert the fecal stream away from a distal anastomosis or a disease process (Figs. 2 and 2). split ileostomy is uncommonly performed if a loop ileostomy cannot effectively divert the fecal stream. The intestine is divided, and the efferent limb is closed and left in proximity to the stoma to be easily found at a future surgery [1, 2]. Water-soluble contrast material often is administered via the rectum to assess anastomotic integrity before takedown of a loop ileostomy [6]. ntegrade opacification via the ileostomy stoma may also be performed [7]. Multiplanar imaging techniques such as CT and MRI allow accurate evaluation of ileostomies [8]. Normal natomy and Variants n understanding of the anatomy and of the wide range or normal variants facilitates the diagnosis of diseases processes. CT and MR features of a normal ileostomy include thin and regular stoma wall without ulcerations or fistula, with homogeneous enhancement after IV injection of a contrast agent similar to other nearby normal intestinal loops. Peristomal fat is homogeneous. Minimal stranding of the peristomal fat is frequently observed (Fig. 1). fferent and efferent segments of the ileostomy are not redundant or under tension. Nonspecific inflammation in the distal portion of the ileum abutting the ileostomy stoma or tapered narrowing of bowel where it traverses the fascial planes of anterior abdominal wall may sometimes be observed (Figs. 3 and 3). In all cases, only a short segment of the ileostomy is involved, without fistula or marked fat stranding (Figs. 3 and 3). Redundancy of the ileal loop may also be observed, particularly in cases of longstanding end ileostomy in patients with a fatty subcutaneous plane (Fig. 4). Similarly, ileostomy prolapse characterized by a protrusion of the ileum outside the abdominal wall through the stoma may be observed in patients with long-standing end ileostomy (Figs. 5 and 5). JR:196, March

2 El Mouhadi et al. Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved Complications Intestinal Obstruction Intestinal obstruction is a frequent complication, observed in 5% of cases before closure and in up to 15% of cases after closure of the stoma [4]. Obstruction can be functional or related to a mechanical obstruction. Mechanical obstruction may be caused by intraabdominal adhesions from the previous laparotomy or by a twist of the proximal loop of the ileostomy [3]. CT shows prestomal dilated intestinal loops and the level of the obstruction. CT further permits morphologic differentiation of distal obstruction related to twist of the distal portion of the ileum (Figs. 6 and 6) from more proximal obstruction related to adhesion (Figs. 7 and 7). Parastomal Hernia Parastomal hernia is a common late complication usually observed more than 2 years after construction of the ileostomy [9]. This incisional hernia is symptomatic in 10% of cases. The parastomal hernia is less frequent after ileostomy than after colostomy [10]. Several complications can occur, the most severe of which is the strangulation of herniated loops leading to intestinal obstruction and ischemia. Visualization of small-bowel loops in the anterior abdominal wall is a characteristic feature of parastomal hernia (Figs. 8 and 8). CT detects subclinical hernia and defines the position (lateral to the stoma in 80% of cases), size, and content of parastomal hernias. Stomal Recurrence of Crohn Disease Crohn disease can involve ileostomy limbs. High-signal-intensity protrusions into the stoma wall are related to mucosal deep ulcerations [11] (Figs. 9 9E). Wall thickening with intense mural enhancement after IV injection of a contrast agent is secondary to advanced inflammation (Figs. 9 9E). The length of the inflammatory involvement and associated signs (e.g., fistula, abscess, stenosis, and mural enhancement) are important features to differentiate a recurrence of Crohn disease from a nonspecific stoma inflammation that only involves the distal portion of the ileum abutting the stoma. Fistula Periileostomy fistula is usually related to the recurrence of Crohn disease and reflects the extension of the inflammation directly into the subcutaneous tissues alongside the stoma walls [11]. Peristomal fistula is observed in 20% of patients with Crohn disease and can lead to peristomal abscess (Figs. 10 and 10). CT and MRI define the location and extent of the fistula, which may be outlined by enteral contrast medium and is seen as linear tracks of high signal intensity on T2- weighted MRI scans. lternatively, fistulas are also seen as enhancing extraenteric tracks highlighted by abnormal enhancement without luminal enteric contrast. Complications Related to Preexisting Disease Other abnormalities related to preexisting disease may also be observed, such as radiation-induced enteritis (Figs. 11 and 11). Collections and abscesses also may be observed. In the postoperative period, collections frequently are related to anastomosis leak or small-bowel fistula (Figs. 12 and 12). Ileostomy Enteroliths Enteroliths are an uncommon complication that can cause intestinal obstruction at the site of ileostomy. The enterolith is primary when it arises in the bowel lumen (e.g., phytobezoar) or secondary when it forms outside the bowel lumen (e.g., gallstone ileus). Primary enterolith formation is usually related to intestinal stasis [12]. Diagnosis is easily performed with CT scans (Figs. 13 and 13). Peristomal Varices This complication can be observed in any patient presenting with portal hypertension and a surgical stoma [13]. CT and MRI show localization of enlarged peristomal veins and may detect the localization of active bleeding (Fig. 14). leeding stomal varices are difficult to manage. Local pressure, cautery, coil embolization, transjugular intrahepatic portosystemic shunt, and surgical shunt have been proposed to stop bleeding. Other complications, such as tumor recurrence and stoma adenocarcinoma, are markedly uncommon [14] (Figs. 15 and 15). In conclusion, it is important for radiologists to be aware of CT and MRI features of ileostomies because of the implications for patient care. References 1. Hodgson WJ. Construction and closure of temporary loop ileostomy. J m Coll Surg 2006; 202: Guenaga KF, Lustosa S, Saad SS, Saconato H, Matos D. Ileostomy or colotomy for temporary decompression of colorectal anastomosis. Cochrane Database Syst Rev 2007; 24:CD Shellito PC. Complications of abdominal stoma surgery. Dis Colon Rectum 1998; 41: Robertson I, Leung E, Hughes D, et al. Prospective analysis of stoma-related complications. Colorectal Dis 2005; 7: Muneer, Shaikh R, Shaikh G, Qureshi G. Various complications in ileostomy construction. World ppl Sci J 2007; 2: org/wasj/wasj2%283%29/7.pdf 6. Kessler JM, Levine MS, Rubesin SE, Rombeau JL, Laufer I. ccuracy of retrograde ileostomy radiographic examination for detecting smallbowel abnormalities. JR 2008; 190: Schutz JCL, Levine MS, Woo EY, Rombeau JL. ntegrade ileography for evaluating a distal anastomotic stricture after loop ileostomy. JR 2005; 184:S56 S57 8. Jaffe T, Martin LC, Thomas J, damson R, De Long DM, Paulson EK. Small-bowel obstruction: coronal reformation from isotropic voxels at 16-section multi-detector row CT. Radiology 2006; 238: Israelsson L. Parastomal hernias. Surg Clin North m 2008; 88: Rondelli F, Reboldi P, Rulli, et al. Loop ileostomy versus loop colostomy for fecal diversion after colorectal or coloanal anastomosis: a metaanalysis. Int J Colorectal Dis 2009; 24: Greenstein J, Dicker, Meyers S, ufses H. Periileostomy fistulae in Crohn s disease. nn Surg 1983; 197: Fox ER, Chung T, Laufer I. Enteroliths in a continent ileostomy. JR 1988; 150: Spier J, Fayyad, Lucey MR, et al. leeding stomal varices: case series and systematic review of the literature. Clin Gastroenterol Hepatol 2008; 6: Metzger PP, Slappy L, Chua HK, Menke DM. denocarcinoma developing at an ileostomy: report of a case and review of the literature. Dis Colon Rectum 2008; 51: JR:196, March 2011

3 Imaging Features of Ileostomies Fig year-old woman with permanent end ileostomy after total proctocolectomy for ulcerative colitis. Minimal stranding (arrows) of subcutaneous fat is seen. Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old-woman who underwent loop ileostomy to protect ileal pouch. and, Normal appearance of loop ileostomy is seen on CT () and MRI () scans. Fig year-old woman with history of subtotal colectomy and ileosigmoid anastomosis for Crohn disease and consecutive rectal amputation with definitive end ileostomy for rectal adenocarcinoma., Thickening (arrow) is seen on T2-weighted MRI scan., Contrast enhancement (arrow) of distal portion of ileum is seen on T1-weighted MRI scan after gadolinium injection. No clinical or endoscopic features of Crohn disease recurrence were seen at long-term follow-up. JR:196, March

4 El Mouhadi et al. Fig year-old woman with fatty subcutaneous plane. Redundancy of ileal loop is seen. Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old woman with permanent end ileostomy performed 2 years before for ileocolic Crohn disease. and, Ileostomy prolapse with protrusion of ileum outside abdominal wall through stoma is seen on balanced T1/T2-weighted MRI scans in transverse () and sagittal () planes. Fig year-old man with loop ileostomy performed to protect colorectal anastomosis. Smallbowel obstruction occurred 5 days after surgery., Small-bowel dilatation is seen., CT scan in sagittal plane shows that transition zone between dilated and flat ileum is distal when ileum abuts ileostomy (arrow) because of twist of loop ileostomy. Surgical refection of stoma was performed. 580 JR:196, March 2011

5 Imaging Features of Ileostomies Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old man with loop ileostomy performed to obtain temporary diversion of fecal stream during severe pancreatitis., CT scan in frontal plane shows marked dilatation of proximal ileum., Transition zone (arrow) is well demonstrated in sagittal plane. Distal ileum is flat from transition zone to stoma. Occlusion resolved after conservative treatment. Fig. 8 Parastomal hernia in 43-year-old woman with history of total proctocolectomy with definitive end ileostomy for colic Crohn disease. and, T2-weighted MRI scans in axial () and frontal () planes show small-bowel loops medial and lateral to stoma. Fig year-old woman with history of total coloproctectomy with definitive end ileostomy performed 23 years earlier for Crohn disease. and, Wall thickening of long segment of distal ileum is seen on T2-weighted MRI scans. Ulceration (arrow, ) is seen. (Fig. 9 continues on next page) JR:196, March

6 El Mouhadi et al. Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved E C Fig. 9 (continued) 56-year-old woman with history of total coloproctectomy with definitive end ileostomy performed 23 years ago for Crohn disease. C and D, Intense enhancement after gadolinium injection is seen. Ulceration (arrow, C) is seen. E, Deep transmural ulceration (arrow) is seen in sagittal plane. Fig year-old man with total coloproctectomy and definitive end ileostomy for Crohn disease. and, T1-weighted MRI scans obtained after gadolinium injection show intense enhancement of stoma wall related to Crohn disease recurrence. Periileostomy fistula (arrow, ) is seen with small peristomal abscess (arrowhead, ) within subcutaneous fat. D 582 JR:196, March 2011

7 Imaging Features of Ileostomies Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old woman with loop ileostomy performed to protect distal coloanal anastomosis after radiation therapy and proctectomy for rectal carcinoma. and, CT scans in transverse () and sagittal () planes show collection related to small-bowel perforation. Thickening of distal ileum with edema of submucosa is related to radiation-induced enteritis. Fig year-old woman with end ileostomy after ileocolectomy for cancer., Large retroperitoneal collection (asterisk) is seen. It contains air fluid level and contrast media related to fistula (arrow) of distal ileum detected after contrast media ingestion., There is issue of peritoneal collection (asterisks) at both sides (arrows) of ileostomy (I). In early postoperative period, defect around ileal loop is not obliterated. Fig year-old woman with end ileostomy performed after ileocolectomy for cancer. and, Nonocclusive intrastomal stones are seen on axial () and sagittal () slices within bowel lumen. Surgery was complicated by several anastomotic leaks and patient received parenteral nutrition. JR:196, March

8 El Mouhadi et al. Downloaded from by on 12/27/17 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old man with end ileostomy for peritoneal recurrence of sarcoma., Peristomal metastases are seen as round masses (arrows)., Two-month follow-up scan shows massive tumor recurrence. Fig year-old man with loop ileostomy performed to protect coloanal anastomosis after proctectomy for cancer. Patient presented with bleeding stomal varices. Enlarged peristomal veins (arrow) and systemic parietal veins (arrowheads) are well seen. Portal hypertension was observed after right portal vein surgical ligation before right hepatectomy for hepatic metastases. 584 JR:196, March 2011