Nowadays, large numbers of ileostomies and colostomies are created during surgical management of a variety of intestinal disorders. Depending on indication, surgical technique and emergency versus elective conditions, stomas may be either temporary or permanent. As a result, patients with ileostomies and colostomies are commonly encountered in Radiology departments, particularly during perioperative hospitalisation following stoma creation or before recanalisation, and when needing CT or MRI studies for follow-up of operated tumours or chronic inflammatory bowel diseases. However, the stoma site is commonly overlooked on cross-sectional imaging. Aiming to improve radiologists’ familiarity with stoma-related issues, this pictorial essay concisely reviews indications and surgical techniques for ileostomies and colostomies, and presents state-of-the art multimodal imaging in patients living with a stoma, including water-soluble contrast stomal enema (WSC-SE), CT and MRI techniques, interpretation and expected findings. Afterwards, the clinical features and imaging appearances of early and late stoma-related complications are illustrated with imaging examples, including diversion colitis. When interpreting cross-sectional imaging studies, focused attention to the stoma site and awareness of expected appearances and of possible complications are required to avoid missing significant changes requiring clinical attention. Additionally, dedicated imaging techniques such as WSC-SE and combined CT plus WSC-SE may be helpful to provide surgeons the appropriate clinical information required to direct management. Keywords: Ileostomy, Colostomy, Contrast enema, Computed tomography (CT), Magnetic resonance imaging (MRI) Key points Introduction Intestinal stomas, from the Greek word meaning Radiologists often encounter patients with “mouth”, are temporary or permanent artificial openings temporary or permanent ileostomies and of the bowel and are categorised according to the digest- colostomies ive tract segment that is surgically connected to the skin. Particularly in the early postoperative setting, In the United States, each year approximately 150,000 stomas require focused CT/MRI interpretation stomas are created, almost equally divided between ile- Water-soluble contrast enema may be performed via ostomies and colostomies. An estimated 800,000 people colostomy or loop ileostomy currently live with a bowel stoma, of which 40 to 60% Early stoma-related complications include ischemia/ will never undergo surgical closure. With an appropriate necrosis, retraction and abscess enterostomal therapy, well-constructed stomas provide Other complications include prolapse, parastomal patients an acceptable quality of life with few lifestyle hernia, obstruction/strangulation and diversion limitations. Conversely, complications related to the colitis stoma can have a dramatic impact on patients’ physical and mental health . Aiming to improve radiologists’ familiarity with stoma-related issues, this pictorial essay provides a con- Correspondence: email@example.com Department of Radiology, “Luigi Sacco” University Hospital, Via G.B. Grassi 74, cise review of indications and surgical techniques of 20157 Milan, Italy © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Tonolini Insights into Imaging (2019) 10:41 Page 2 of 15 ileostomies and colostomies, then presents state-of-the ileal loop through the abdominal wall and is typically located art multimodal imaging including water-soluble contrast in the right lower quadrant (Fig. 1). The majority of perman- stomal enema (WSC-SE), CT and MRI techniques and ent end ileostomies are created after total proctocolectomy expected findings in patients with an intestinal stoma. for chronic IBD or familial polyposis, when a reservoir (such Afterwards, the key early and late stoma-related compli- as an ileal pouch) is not created. On the other hand, colos- cations are discussed with examples, including diversion tomies are termed according to the segment of the large colitis. bowel that is connected to the skin, and the majority of them are created in the left lower quadrant (Fig. 1). Per- Indications and surgical techniques manent end colostomies are created when the anorectum Intestinal stomas are created, either in emergency situations is removed such as during abdomino-perineal resection or during elective surgery, to manage a variety of benign (APR) and when stoma reversal is not possible, such as for and malignant disorders encompassing colorectal cancer unresectable CRC or palliation of incontinence. The most (CRC), chronic inflammatory bowel diseases (IBD), acute common temporary end colostomy is created during diverticulitis, bowel perforation, ischemic colitis, radiation Hartmann’s surgery for acute diverticulitis or CRC of the colitis, faecal incontinence, intractable perianal sepsis and sigmoid colon, when the closed rectal stump is left in rectovaginal fistulas. The rationale for stoma creation may place for future restoration of intestinal continuity [2–4]. be relief of distal obstruction, protection of an anastomosis, Loop stomas are created at bowel segments with a temporary bypass or definite diversion of the faecal stream. mesentery (such as the ileum, transverse or sigmoid) by Depending on the procedure and the indication, stomas pulling out a loop of bowel through the abdominal wall can be either permanent or temporary [2–4]. up to its external surface, may be secured using a rod, Technically, stomas can be fashioned as either loop or and are opened on one side to create an afferent (proximal) end. In the latter case, the only termination of the bowel and an efferent (distal) limb; thus, it has two openings, of opens at the abdominal wall and the other end is either re- which one empties the bowel and the other is connected to moved or over sewn. An ileostomy involves opening a distal the diverted segment. During surgeries with primary Fig. 1 Sites and names of intestinal stomas. Legend: 1) ileostomy, 2) cecostomy, 3) ascending colostomy, 4) transverse colostomy, 5) descending colostomy, 6) sigmoid colostomy Tonolini Insights into Imaging (2019) 10:41 Page 3 of 15 bowel-to-bowel anastomosis, a temporary diverting loop length and possible stricture before recanalisation. For in- stoma is frequently created, in order to improve healing by stance, at our Institution WSC-SE is generally performed defunctioning the intestine and minimising the impact of before ileostomy takedown after restorative proctocolect- faecal contamination, pressure and tension. These situa- omy and before recanalisation of Hartmann’ssurgery.How- tions mostly include prevention of dehiscence at a high-risk ever, routine WSC-SE prior to closure of defunctioning bowel anastomosis, such as after ileocecal resection for ileostomy remains controversial, since some studies shown Crohn’s disease or during two-stage restorative proctoco- that it rarely provides additional information leading to lectomy with ileal pouch-anal anastomosis for ulcerative modification of patient management . The key contra- colitis. After a variable delay (two to six months), temporary indication for WSC-SE is radiographically confirmed ileostomies are generally reversed (closed) to re-establish bowel obstruction, a situation in which the use of CT is the intestinal continuity. Alternatively a double-barrelled advisable and which will be discussed later on. colostomy may be created, which is similar to loop stomas because it has two openings, when after resection of a dis- Technique eased tract both limbs are exteriorised at the same site at Apart from fasting, patients with an ileostomy do not re- the abdominal wall [2–4]. quire any special preparation. Conversely, prior to WSC-SE colostomies should receive preliminary bowel Water-soluble contrast stomal enema cleansing using irrigation, using the same manoeuvers Rationale and indications many patients already use to regulate their stoma. The pa- Surgeons commonly request WSC-SE via colostomy or tient is placed supine on the fluoroscopy table. After re- loop ileostomy to either A) check for integrity of a distal moving the stoma appliance and cleaning the peristomal bowel anastomosis, particularly in patients at high risk of skin, the radiologist or the referring surgeon may perform complications, or B) assess the bowel anatomy, residual a gentle examination of the stoma using the little finger, in Fig. 2 Technique and normal appearances of water-soluble contrast enema (WSC-SE) using an inflated Foley catheter (thick arrows) passed through the stoma. a In a patient with long-standing Crohn’s disease, WSC-SE performed via end ileostomy in the right iliac fossa shows the radio-opaque diluted contrast medium filling the upstream small bowel, without signs of stricture or dilatation. b Following right colectomy, WSC-SE at defunctioning ileostomy depicts the normal termino-lateral ileo-transverse anastomosis (arrow) without anastomotic leakage. c After recent sigmoidectomy with primary anastomosis, WSC-SE shows patent residual colon up to the rectum, without extraluminal leakage. d Before planned ileostomy takedown, after restorative proctocolectomy for ulcerative colitis, WSC-SE via the efferent limb opacifies the small bowel up to the newly created ileal pouch (o) Tonolini Insights into Imaging (2019) 10:41 Page 4 of 15 Fig. 3 Three examples of WSC-SE performed via colostomy. a After recent Hartmann’s surgery, retrograde opacification of closed rectal stump (o) was performed prior to WSC-SE at the descending colostomy. b In a different patient, WSC-SE performed at the efferent limb of a double- barrelled colostomy at the left iliac fossa depicts the diverted rectosigmoid tract. c at the end of a WSC-SE study, contrast opacifies the vagina (arrowhead) indicating the presence of a rectovaginal fistula particular to identify the two openings of a loop or dou- Cross-sectional imaging of intestinal stomas ble-barrelled stoma. A lubricated urinary-type Foley catheter CT and CT-enterography: Technique and interpretation is introduced into the stoma approximately 15 cm into the Nowadays, the vast majority of operate patients with an bowel lumen and inflated using a few milliliters of saline. intestinal stoma commonly receive contrast-enhanced Then, the catheter is connected to the nozzle of the enema CT, mostly to investigate suspected postoperative com- bag, filled with water-soluble contrast medium such as 1:1 plications or during oncologic follow-up. Additionally, diluted diatrizoate meglumine - diatrizoate sodium solution patients with Crohn’s disease are frequently investigated (Gastrografin®, Bracco, Milan, Italy). The attending radiolo- using CT-enterography after gradual ingestion of gist witnesses the progressive filling of the bowel lumen con- iso-osmotic material such as polyethylenglycole (PEG). nected to the stoma on fluoroscopy, and captures Before CT-enterography, patients with an ileostomy appropriate panoramic and focused frontal, oblique and should not receive laxatives but liquid diet only. Due to panoramic views (Fig. 2). Examples of WSC-SE performed the short transit time through the bowel to the stoma at ileostomies and colostomies are shown in Figs. 2 and 3, (usually about 20 min), to obtain the best diagnostic re- respectively. sult patients should be placed on the scanner table im- The most common abnormal findings include extralum- mediately when the ingested solution begins to fill to inal contrast leakage at the anastomosis and opacification stoma bag . of a fistula (Fig. 3C). At the surgeon’srequest,loop and However, the stoma site is commonly overlooked by double-barrelled stomas may receive WSC-SE along both radiologists interpreting CT studies. Particularly during afferent (upwards) and efferent (downwards) limbs (Fig. 4). the early postsurgical hospitalisation after stoma cre- Furthermore, when combined WSC-SE and rectal enema ation, careful scrutiny of ileostomies and colostomies is is required (such as before colostomy takedown following warranted to avoid missing significant abnormalities. Fo- Hartmann’ssurgery, Fig. 3A), the latter should be per- cused oblique-sagittal CT images parallel to the stomal formed initially since contrast in the right colon and distal segment should be reconstructed, along a plane that is ileum can mask the closed distal stump. usually tilted ventrally 10° to 30° to the ipsilateral side of Fig. 4 Double WSC-SE at a loop ileostomy following recent ileocecal resection for Crohn’s disease, performed via the afferent (a) and efferent (b, c) limbs, obtaining opacification of the residual large bowel up to the rectum Tonolini Insights into Imaging (2019) 10:41 Page 5 of 15 the abdomen (Fig. 5A, see inset) and slightly downwards reported as suggestive of inflammation and requiring clin- (Fig. 6C, see inset). ical attention [7, 8]. Combined CT with stomal enema Expected CT findings In selected patients, performing a one-stop-shop CT The usual CT appearance of an intestinal stoma is a col- plus WSC-SE may be beneficial to provide combined lapsed colonic or ileal loop with uniform mural thick- anatomic and functional/dynamic information. This ness and homogeneous contrast enhancement that technique includes a preliminary unenhanced acquisition traverses the fascial planes of the anterior abdominal wall, of the abdomen followed by a contrast-enhanced CT reaches the external opening and protrudes approximately scanning after cannulation of the stoma and injection of 1–1.5 cm at the cutaneous surface (Fig. 5A). Enteral or iodinated contrast medium such as 5–10% diluted iopa- fecal material flowing through respectively ileostomy or midol (Bracco, Milan, Italy) or iopromide (Schering colostomy into the stomal bag indicates patency of the Pharma, Berlin, Germany) (Fig. 7). stomal tract (Fig. 5B). When assessing loop and double-barrelled stomas, both the afferent and efferent limbs should be identified (Fig. 5B– D). During the early MRI and MR-enterography postoperative days, mild uniform thickening of the stomal Particularly in the setting of IBD, patients with intestinal tract due to oedematous submucosa, inflammatory-type stomas increasingly receive MRI studies. Both CT- and peristomal fat stranding and gas bubbles are commonly MR-enterography are currently recommended by the observed and should not be considered abnormal findings European Crohn’s and Colitis Organization (ECCO) (Fig. 6). Additionally, identification of thickened and guidelines as then current standards for evaluation of the hyperenhancing peristomal skin (Fig. 5C) should be small bowel, and the latter is preferred in young patients Fig. 5 CT reconstruction technique and expected findings of ileostomies. a Focused oblique-sagittal (note lateral obliquity in inset) image of a normal end ileostomy with uniform mural thickness and enhancement of the stomal tract (arrow), mild protrusion at external orifice. b oblique- sagittal images of a loop ileostomy identify non-thickened, collapsed efferent and afferent limbs (arrows). Note fluid flowing at the external orifice indicating stomal patency. c, d A typical defunctioning loop ileostomy with two limbs (arrows) on sagittal (c) viewing and coronal (d) appearance. Note mild thickening and hyperenhancement of peristomal skin in c (compared to a and b) consistent with cutaneous inflammation at physical examination Tonolini Insights into Imaging (2019) 10:41 Page 6 of 15 Fig. 6 Expected early CT findings in newly created stomas. a, b A typical recent ileostomy, with collapsed stomal tract (arrows) showing mild uniform mural stratification (enhancing mucosa and oedematous submucosa). c, d Uncomplicated descending colostomy created 4 days earlier during low anterior rectal resection, with stomal tract (arrows) showing similar features to a, b, surrounded by oedematous fat stranding (*) and gas bubbles as expected postsurgical findings who need several imaging studies during their lifelong MR-enterography well depict the normal, collapsed stomal disease . tracts crossing the abdominal wall, with uniform mural Although discussion of MRI protocols lies beyond the thickness and contrast enhancement comparable to that scope of this article, MR-enterography relies on ingestion of other small bowel loops, mild protrusion of the external of iso-osmotic biphasic material such as PEG solution. orifice (Fig. 8A, B). At MR-enterography, fluid flowing Such as during CT-enterography, also in the MRI suite from the stoma into the bag confirms bowel and stomal patients with an ileostomy should be scanned just when patency (Fig. 8C, D) and peristomal skin inflammatory the ingested solution reaches the stoma. MRI and changes are readily identified (Fig. 12)[8, 10]. Fig. 7 Combined CT plus WSC-SE in a patient with iatrogenic rectal perforation during stricture dilatation. Axial CT image (a) showing large hyperattenuating collection in the right abdomen (+) and diluted iodinated contrast medium injected in the cannulated efferent limb of the loop colostomy (thick arrows). Maximum-intensity projection reconstructions (b, c) depict the contrast medium-filled diverted rectosigmoid colon with stricture (thin arrows), without extraluminal leakage. Note drainage tubes in place Tonolini Insights into Imaging (2019) 10:41 Page 7 of 15 Fig. 8 Normal appearance of ileostomies at MR-enterography in two patients operated for Crohn’s disease. a, b Axial fat-suppressed T2-weighted (a) and sagittal post-gadolinium fat-suppressed T1-weighted (b) images showing collapsed stomal tract (arrow) traversing the abdominal wall, with normal mural thickness and contrast enhancement comparable to that of other small bowel loops. c, d Axial T2- (c) and post-gadolinium fat-suppressed T1-weighted (d) images showing collapsed stomal tract (arrow), mild protrusion at external orifice (thin arrows), and abundant fluid flowing within stoma bag consistent with stomal patency Fig. 9 Stoma retraction appearing as depressed, thickened and irregular skin (thin arrows) at the site of a descending colostomy with elongated collapsed tract (arrows). Note distended small bowel loops with feces (*) consistent with obstruction Tonolini Insights into Imaging (2019) 10:41 Page 8 of 15 Fig. 10 Three cases of stomal abscesses, all of which required surgical treatment. a, b Ill-defined collection (+) with mixed fluid and air content occupying the subcutaneous fat at the site of a recent ileostomy (arrow in a). c Large fluid collection (+) with thin walls abutting the lateral aspect of the ileostomy (arrow), following recent anterior rectal resection. d-f A typical abscess (+) with thickened enhancing walls and air-fluid level within a parastomal hernia (PH), following colectomy for Crohn’s disease Fig. 11 Clinically confirmed protrusion of an ileostomy with markedly oedematous stomal tract (arrows) and bulging of external orifice (thin arrows), which was managed conservatively Tonolini Insights into Imaging (2019) 10:41 Page 9 of 15 Fig. 12 Reactivation of Crohn’s disease at an ileostomy. a, b CT showing diffuse, mildly irregular mural thickening with marked contrast enhancement along the stomal tract and the distal small bowel, consistent with active disease (also note fat stranding and fluid in the right parietocolic gutter). c, d In the same patient, MR-enterography confirms thickened walls on T2-weighted (c) with hyperenhancement on post-gadolinium fat-suppressed (d) images. Additionally, note enhancing inflamed peristomal skin (thin arrows in a, b and d) Stoma-related complications: An overview Early stomal complications In the literature, reported rates of stoma-related morbid- Stomal ischemia and necrosis ity vary from 2.9% to 81.1% according to stoma type, in- Ischemia results from inadequate blood supply to the re- dication and underlying disease, elective or emergent cently created stomal tract and most usually complicates surgery, patient factors (such as obesity and comorbidi- colostomies, in association with obesity and emergency ties) and definition of complications. The incidence of operations. Although rare, necrosis is generally a severe complications is higher in end colostomies, followed by event which may require emergency surgical revision, loop colostomies and ileostomies. Conversely, small depending upon the depth of the ischemic segment. Vas- bowel obstruction more commonly occurs with the lat- cular impairment to the newly created stoma may be ei- ter . ther superficial (in 2–13% of patients) or deep to the Stoma-related complications may occur early or fascia (0.37–3%). Necrosis is diagnosed clinically at phys- late after creation. The very common peristomal skin ical examination, and emergency CT may be performed and metabolic (dehydration, electrolyte imbalance) problems will not be discussed in this radiological Table 1 Clinical classification of parastomal hernias by the review. Within 30 days from surgery, common early European Hernia Society (EHS). Additionally, parastomal hernias complications include ischemia/necrosis, stoma re- are categorised as either primary (P) or recurrent (R) traction and parastomal abscess. Conversely, late oc- Size of the abdominal wall defect currences include parastomal hernia (PH), stomal Small (< 5 cm) Large (> 5 cm) prolapse and varices. Bowel obstruction and strangu- Concomitant incisional hernia I III lation may occur both as early or late complications Absent incisional hernia II IV [12, 13]. Tonolini Insights into Imaging (2019) 10:41 Page 10 of 15 Table 2 CT-based classification system of parastomal hernias. Note: size of the hernia sac differs from that of the abdominal wall defect in EHS clinical classification (Table 1) CT Type Description 0 Peritoneum follows the wall of the bowel forming the stoma, without sac formation Ia Hernia containing bowel loop forming the colostomy with sac < 5 cm Ib Hernia containing bowel loop forming the colostomy with sac < 5 cm II Hernia containing omentum III Hernia containing other intestinal loop than the bowel forming the stoma to assess the depth of the hypo- or nonenhancing ischae- occurs in approximately 3% of ileostomies and 2% of mic bowel conduit [12, 13]. colostomies, in association with risk factors such as ad- vanced age, obesity and obstruction at time of creation. Stomal retraction Sometimes associated with a PH, prolapse may either Retraction occurs in 1.4–9% of patients with both ileo- fixed or sliding (intermittent, related to increased ab- and colostomies. During the early postoperative period, dominal pressure and reducible). Prolapse may be identi- retraction is caused by excessive tension on the con- fied at cross-sectional imaging (Figs. 8C, 11), tends to nected bowel loop, and if untreated may cause involve the efferent limb of loop stomas, and may re- long-term stricture. Later, retraction may develop with quire surgical revision, resection or relocation . or without a coexisting PH, and should be suggested when imaging shows loss of the normal external bulging Stomal recurrence of Crohn’s disease or cutaneous depression (Fig. 9). A not-unusual diagnosis at CT- and MR-enterography in operated patients, recurrent Crohn’s disease at an ileos- Stomal abscess tomy shows the usual cross-sectional features of the Most usually developing within the first weeks after sur- treated IBD along the stomal tract, such as circumferen- gery, at cross-sectional imaging abscesses show the tial mural thickening with intense or stratified enhance- well-known appearance as mixed fluid and gaseous col- ment (Fig. 12)[8, 14]. lections of variable size with enhancing periphery, lo- cated in the subcutaneous tissue abutting the stomal Parastomal hernia tract, usually surrounded by inflammatory fat stranding A subtype of incisional hernia, PH is defined by the (Fig. 10)[3, 12, 13]. European Hernia Society (EHS) as an abnormal protru- sion of contents of the abdominal cavity through the ab- Long-term stomal complications dominal wall defect created during placement of a Stomal prolapse colostomy or ileostomy . Prolapse refers to excessive, full-thickness protrusion of Although difficult to assess due to lack of a uniform the stomal tract bowel at the cutaneous opening and definition and inadequacy of physical examination, the Fig. 13 Elongated, patent permanent descending colostomy (arrows) containing feces in a patient with history of abdomino-perineal resection, without formation of hernia sac, consistent with type 0 PH Tonolini Insights into Imaging (2019) 10:41 Page 11 of 15 prevalence of PH progressively increases over time. peristomal bulging during cough, pain, discomfort, Within 5 years, some degree of PH is reported in 48% of difficulty holding the stoma appliance in place, leak- end colostomies and 28.3% of end ileostomies. The inci- age of bowel contents and peristomal dermatitis. Indi- dence is much lower in loop ileostomies (6.2%) since cations for surgical repair include obstruction, they are generally temporary stomas and PH has not incarceration, prolapse, stenosis and malfunctioning, sufficient time to develop. Risk factors include ad- large size and patient preference due to pain, intract- vanced age, obesity, cancer, diabetes, malnutrition, in- able dermatitis or cosmetic reasons [13, 16, 17]. creased intra-abdominal pressure and chronic Nowadays, CT is recognised as the technique of choice obstructive lung disease. Nowadays, primary preven- to 1) detect smaller, clinically non-apparent PH, 2) con- tion with prophylactic mesh placement during stoma firm the clinical diagnosis and 3) characterise content creation is the established measure to decrease the and stage the PH. Aiming to decrease uncertainty rate of PH development. The majority (75%) of pa- among different surgical classifications, the EHS catego- tients complain from PH-related symptoms such as rises PH according to the size of the abdominal wall Fig. 14 Three cases of uncomplicated PH. a, b CT type Ib PH measuring approximately 6 cm in size containing a redundant ileostomy tract (arrows). c, d Larger PH containing a large portion of the right colon. e, f Type III PH following recent Hartmann’s surgery containing the oedematous colostomy tract (arrows) and some small bowel loops Tonolini Insights into Imaging (2019) 10:41 Page 12 of 15 defect and on the coexistence of another incisional her- patients with ileostomies and colostomies, CT generally nia (Table 1). allows identification of the transition point and is there- Additionally, a CT-based staging system (Table 2)has fore useful to differentiate local (stoma-related) causes been proposed, which relies on the size and content of such as a twisted stomal tract (Fig. 16A) or entrapment the hernia sac. A long, redundant stomal tract in within a PH (Fig. 16B,C), from more proximal obstruc- long-standing PH (grade 0, Fig. 13) is considered a nor- tion causes such as intra-abdominal adhesions or other mal appearance. The key differentiation provided by CT hernia (Fig. 16D) and alternative diagnoses such as bowel is between grade I and grade III hernias, the latter con- encasement of loops by neoplastic tissue (Fig. 16E,F) [3, taining other bowel loops than the stomal tract (Fig. 14) 8]. [18, 19]. Closed-loop obstruction refers to obstruction with two Furthermore, the presence of a PH is commonly in- adjacent transition points and may be further complicated volved in the development of further complications such by strangulation. Findings consistent with ischaemia in- as stomal retraction, abscess (Fig. 10), prolapse, clude C-shaped loop, thickened walls, absent or dimin- closed-loop obstruction and strangulation (Fig. 15)[13, ished mural enhancement, mesenteric fluid (Fig. 15). 16, 17]. Diversion colitis Stoma-related bowel obstruction and strangulation Initially described in 1981, diversion colitis (DC) refers Mechanical obstruction occurs in at least 5% of patients to a nonspecific mucosal inflammation of diverted rectal with a stoma and may result from a variety of causes, re- or colonic segments by a loop or end colostomy. The lated to the stoma, previous surgery or underlying dis- mechanism is poorly understood and may involve stasis, ease. In the vast majority of situations, CT represents ischaemia, loss of essential nutrients from enteric bacteria the ideal technique for investigating patients with clin- or overgrowth of harmful bacteria in the diverted segment. ical or plain radiographic signs of obstruction. In The unspecific endoscopic appearances include mucosal Fig. 15 Two surgically treated complications of PH. a, b Right-sided PH containing ileostomy tract (arrows) and another herniated small bowel (arrowheads) in a closed-loop obstructive pattern with markedly thickened walls and hypoenhancing submucosa, consistent with ischemia. c, d Strangulation with extensive small bowel infarction in a patient with PH at permanent colostomy: note dilated fluid-filled enteric loops (*), some of them with non-enhancing walls indicating necrosis Tonolini Insights into Imaging (2019) 10:41 Page 13 of 15 Fig. 16 Surgically confirmed obstructed stomas and alternative diagnoses. a Sagittal image showing sharply angulated stomal tract (arrow) causing upstream obstruction. b, c Entrapment with upstream dilatation of large bowel (arrowhead in c) within a large PH in a patient with Crohn’s disease and permanent ileostomy (arrow in b). Note peristomal fluid (+) and gas bubbles consistent with recent surgery. d Incisional hernia (arrowhead) causing obstruction, in a patient with uncomplicated ileostomy (arrow). e, f Blockage of ileostomy (arrow) from solid tissue (*) consistent with peritoneal carcinomatosis erythema, oedema, friability, granularity and erosions. Cor- are ruled out by negative stool cultures. Treatment con- responding histologic patterns include mild or moderate sists in irrigation of the diverted colon with fatty-acids chronic and acute inflammatory changes, crypt atrophy or butyrate enemas, or surgical reconstruction if feasible. and distortion, follicular lymphoid hyperplasia. At CT (Fig. 17A-C) diversion colitis should be suggested Within a few months from initial surgery, DC tends when nonspecific “proctocolitis” appearance are seen in to develop in nearly all patients with diversion cre- the closed rectal stump in patients with a colostomy, in- ated for any pathology. Features consistent with DC cluding an increased wall thickness (over 3–4 mm) with are reported in 91% of patients with pre-existing stratified “target” or “water halo” appearance corresponding IBD and 70-74% of other patients, without associ- to inflamed mucosa, oedematous hypoenhancing sub- ation with sex, age, type of stoma and surgical tech- mucosa [3, 23]. MRI even better shows mural oedema and nique. Furthermore, DC is frequently (60–70% of perivisceral inflammatory changes (Fig. 17D–F). Unfortu- patients) asymptomatic and therefore overlooked. nately, these cross-sectional imaging closely resemble those Symptoms may include pelvic discomfort, anorectal of active IBD, therefore integration with clinical and endo- pain, tenesmus, mucous or bloody discharge, and are scopic information is required when recanalisation is being unrelated with severity of histologic changes. Inter- considered in patients with underlying IBD [21, 22]. estingly, symptoms and inflammation are reversible after restoration of intestinal continuity [21, 22]. Conclusion The diagnosis of diversion colitis relies on a combin- Patients with ileostomies and colostomies are commonly ation of history, symptoms, endoscopic and histological encountered in Radiology departments, such as during findings. Infections such as pseudomembranous colitis perioperative hospitalisation following stoma creation or Tonolini Insights into Imaging (2019) 10:41 Page 14 of 15 Fig. 17 Two cases of diversion proctitis. a-c) a year after colectomy and terminal ileostomy for Crohn’s disease, initial CT (a) performed for perineal pain showed fluid-filled inflamed rectal stump with uniformly thick walls (thin arrows), mesorectal engorgement (*) and presacral fluid (arrowhead). Despite transanal drainage of fluid, repeated CT three months later (b-c) showed increased thickness and appearance of stratification at inflamed rectal walls (thin arrows). d-f) following colonic resection for indeterminate colitis, MRI including sagittal T2- (a), fat-suppressed axial T2- and post-gadolinium fat-suppressed T1-weighted (C) sequences showed markedly thickened oedematous and hypervascular rectal walls (thin arrows), perirectal fluid (*) and downwards invagination of the closed apex of rectal stump (arrowheads) before recanalisation, or during cross-sectional imaging Ethics approval and consent to participate Not applicable. studies requested for follow-up of operated tumours or chronic IBD. When interpreting cross-sectional imaging Consent for publication studies, focused attention to the stoma site and Not applicable. awareness of expected appearances and of possible com- plications are required to avoid missing significant ab- Competing interests normalities. Additionally, specific imaging studies such The author declares that he has no competing interests. as WSC-SE and combined CT plus WSC-SE may be helpful to provide surgeons the appropriate clinical in- Publisher’sNote formation required to direct management. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Abbreviations Received: 8 January 2019 Accepted: 8 February 2019 APR: Abdomino-perineal resection; CRC: Colorectal cancer; CT: Computed tomography; DC: Diversion colitis; ECCO: European Crohn’s and Colitis Organization; EHS: European Hernia Society; IBD: Inflammatory bowel diseases; MRI: Magnetic resonance imaging; PEG: Polyethylenglycole; References PH: Parastomal hernia; WSC-SE: Water-soluble contrast stomal enema 1. Martin ST, Vogel JD (2012) Intestinal stomas: indications, management, and complications. Adv Surg 46:19–49 2. 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Insights into Imaging – Springer Journals
Published: Mar 29, 2019
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