CT imaging of chronic radiation enteritis in surgical and non surgical patients

CT imaging of chronic radiation enteritis in surgical and non surgical patients Poster No.: C-0334 Congress: ECR 2017 Type: Educational Exhibit Authors: M. Zappa, S. Kemel, C. Bertin, M. Ronot, D. Cazals-Hatem, Y. 1 1 1 1 2 1 1 1 1 2 Panis, F. Joly, V. Vilgrain ; Clichy/FR, Paris/FR Keywords: Small bowel, CT, Diagnostic procedure, Toxicity, Obstruction / Occlusion DOI: 10.1594/ecr2017/C-0334 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 36

Learning objectives 1. To describe and illustrate CT findings in patients with chronic radiation enteritis (CRE) 2- To highlight those associated with surgery Page 2 of 36

Background Radiation therapy plays an important role in the treatment of many pelvic cancers, but, despite advances in treatment techniques, healthy tissue toxicity remains the most important radiation-dose-limiting factor. During radiation therapy of pelvic cancers, parts of the small bowel, colon or rectum are inevitably included in the treatment field and may often be injured [1]. The terminal ileum and the recto-sigmoid colon are more commonly injured because of their fixed position and proximity to pelvic organs. Most factors which could influence the development of CRE are either patient-related factors such as age, gender, body mass index, and concomitant comorbidities, or treatment-related factors such as radiation dose, fractionation schedule, volume of small bowel in the radiation field, and concomitant use of chemotherapy[2, 3]. Because of its rapid cellular turnover, the small bowel mucosa is the most radiosensitive tissue in the GI tract. Early intestinal injury is primarily a result of cell death in the rapidly proliferating crypt epithelium and a protracted acute inflammatory reaction in the lamina propria. Crypt cell death results in insufficient replacement of the villus epithelium, breakdown of the mucosal barrier and mucosal inflammation [1]. In some patients, this inflammatory process becomes exaggerated and inflammatory process runs a chronic course. Atrophy of the mucosa, fibrosis of the intestinal wall and progressive obliterative endarteritis are prominent and are currently irreversible features[1, 4]. This transmural process is mainly complicated by stricture formation and obstruction. Chronic radiation enteritis typically develops between 6 months and 6 years after radiation therapy, but has been reported to occur up to 20-30 years. CRE is a diagnosis problem as most symptoms (partial small bowel obstruction and malabsorption) are non specific and can also be seen in cancer recurrence, carcinosis or adhesions. One-third of patients will require surgery, although it's associated with high postoperative morbidity and mortality. Imaging may play an important role to help diagnosis in these patients, and to help surgical decision. Because of its good spatial resolution and availability, CT scan should be the modality of choice. Page 3 of 36

Findings and procedure details A-CT scan imaging Sixty one patients who had a CT scan performed for CRE between 2006 and 2016 were reviewed. Forty-four patients had non emergency CT performed after small bowel distension (27 had CT enteroclysis and 17 had oral CT enterography). CT scans were performed before and after an intravenous bolus injection iodinated contrast agent, with a late arterial phase and a portal venous phase acquisitions obtained 35 and 80 seconds after injection of the contrast covering abdomen and pelvis. Seventeen patients had a CT performed in emergency for occlusive episode, with spontaneous small bowel distension. All CT examinations were contrast-enhanced. B- Small bowel CT findings All abnormal small bowel segments were in the ileum. Low distensibility was seen in all abnormal small bowel segments with a mean bowel luminal diameter of 8 mm in abnormal loops and 30 mm in upstream loops, with a mean reduction of 73% (fig.1). Page 4 of 36

Fig. 1: Figure 1: Coronal reconstruction showing marked loss of distensibility of abnormal loop (green arrow) compared to distended upper small bowel (yellow arrows) References: Radiology, Hôpital Beaujon - Clichy/FR Length of the abnormal small bowel was the most of the time at least 20 cm with a continuous disease. Some patients (11%) had several short (1 to 5 cm) strictures separated by normal-appearing bowel (fig.2 and fig.3). Page 5 of 36

Fig. 2: Figure 2: Extended and continuous disease (green arrow), associated with reduction of distensibility + retraction of bowel loops + homogeneous bowel wall enhancement (pattern1) References: Radiology, Hôpital Beaujon - Clichy/FR Page 6 of 36

Fig. 3: Figure 3: Oblique reconstruction showing short strictures (green arrows) separated by distended normal-appearing bowel (yellow arrow) References: Radiology, Hôpital Beaujon - Clichy/FR Small bowel wall thickness was not marked, ranged from 2 to 7 mm (mean, 4 mm), larger than 3 mm in 47.5% of patients (fig.4, fig.5 and fig.6). Enhancement may be marked (69% of patients) or normal for the others, compared to normal loop (fig.5, fig.6 and fig.7). Page 7 of 36

Enhancement was layered for half of patients and homogeneous for the other half (fig.5, fig.6, fig.7 and fig.8). Of course, layered pattern was always associated with marked enhancement, as homogeneous enhancement could be normal or marked. Fig. 4: Figure 4: Small bowel wall thickness measured at less than 4 mm (3 mm) References: Radiology, Hôpital Beaujon - Clichy/FR Page 8 of 36

Fig. 5: Figure 5: Small bowel wall thickness measured at more than 4 mm (6 mm) with normal and homogeneous enhancement References: Radiology, Hôpital Beaujon - Clichy/FR Page 9 of 36

Fig. 6: Figure 6: Small bowel wall thickness measured at more than 4 mm (6 mm) with marked and layered wall enhancement References: Radiology, Hôpital Beaujon - Clichy/FR Page 10 of 36

Fig. 7: Figure 7: Marked and layered small bowel wall enhancement (green arrow) References: Radiology, Hôpital Beaujon - Clichy/FR Page 11 of 36

Fig. 8: Figure 8: Marked and homogeneous small bowel wall enhancement (green arrow) References: Radiology, Hôpital Beaujon - Clichy/FR Valvulae conniventes were most often atrophic (48% of patients), or thickened for 26% of patients; for the others, they were considered as normal (fig.9 and fig.10). Page 12 of 36

Fig. 9: Figure 9: Atrophic valvulae conniventes References: Radiology, Hôpital Beaujon - Clichy/FR Page 13 of 36

Fig. 10: Figure 10: Thickened valvulae conniventes References: Radiology, Hôpital Beaujon - Clichy/FR Involvement of mesentery resulted in retraction of bowel loops (with angulations and tethered loops) in about 60% of patients, associated in half of case to a mesentery thickening (fig.7, fig.8, fig.11 and fig.12) Page 14 of 36

Fig. 11: Figure 11: Retraction of bowel loops (with angulations, green arrow) References: Radiology, Hôpital Beaujon - Clichy/FR Page 15 of 36

Fig. 12: Figure 12: Mesentery thickening (green arrow) with adhesion and retraction of bowel loops (yellow arrow) References: Radiology, Hôpital Beaujon - Clichy/FR C- Frequent associations of CT findings The two most common CT patterns, depicting in 59% of patients, were: 1) pattern 1: extended disease (more 20cm) + continuous disease + reduction of distensibility + retraction of bowel loops + homogeneous bowel wall enhancement, found in 131% of patients (fig.2). Page 16 of 36

Fig. 2: Figure 2: Extended and continuous disease (green arrow), associated with reduction of distensibility + retraction of bowel loops + homogeneous bowel wall enhancement (pattern1) References: Radiology, Hôpital Beaujon - Clichy/FR 2) pattern 2: reduction of distensibility+ marked bowel wall enhancement + layered bowel wall enhancement + bowel wall thickening, found in 28% of patients (fig.13). Page 17 of 36

Fig. 13: Figure 13: Pattern2, with reduction of distensibility+ marked bowel wall enhancement + layered bowel wall enhancement + bowel wall thickening References: Radiology, Hôpital Beaujon - Clichy/FR D- Comparison of CT findings in surgical and non surgical patients Thirty four patients had surgical resection. Surgery was ileocaecal resection for 28 patients and ileal resection for 6 patients. Obstruction was the main symptom for 31(91%) surgical patients (whereas obstruction and diarrhoea was each the main symptom for 13(48%) non surgical patients). Ninetyfour % of patients referred for emergency occlusive episode underwent surgery. Page 18 of 36

Of the CT findings described above, three were significantly associated with surgical resection: - Retraction of bowel loop (74% of surgical patients vs. 41% of non surgical patients), - Homogeneous bowel wall enhancement (65% of surgical patients vs. 33% of non surgical patients), - Atrophic valvulae conniventes (65% of surgical patients vs. 26% of non surgical patients). The most common pattern CT associated with surgery was the pattern 1 described above, found in 50% of patients, but in only 7% of non surgical patients. The combination of the three signs significantly associated with surgery was found in 44% of surgical patients, and in only 11% of non surgical patients (fig.14). Page 19 of 36

Fig. 14: Figure 14: Combination of the three signs significantly associated with surgery (retraction of bowel loop, homogeneous bowel wall enhancement and atrophic valvulae conniventes) References: Radiology, Hôpital Beaujon - Clichy/FR Page 20 of 36

Images for this section: Fig. 1: Figure 1: Coronal reconstruction showing marked loss of distensibility of abnormal loop (green arrow) compared to distended upper small bowel (yellow arrows) Radiology, Hôpital Beaujon - Clichy/FR Page 21 of 36

Fig. 2: Figure 2: Extended and continuous disease (green arrow), associated with reduction of distensibility + retraction of bowel loops + homogeneous bowel wall enhancement (pattern1) Radiology, Hôpital Beaujon - Clichy/FR Page 22 of 36

Fig. 3: Figure 3: Oblique reconstruction showing short strictures (green arrows) separated by distended normal-appearing bowel (yellow arrow) Radiology, Hôpital Beaujon - Clichy/FR Page 23 of 36

Fig. 4: Figure 4: Small bowel wall thickness measured at less than 4 mm (3 mm) Radiology, Hôpital Beaujon - Clichy/FR Page 24 of 36

Fig. 5: Figure 5: Small bowel wall thickness measured at more than 4 mm (6 mm) with normal and homogeneous enhancement Radiology, Hôpital Beaujon - Clichy/FR Page 25 of 36

Fig. 6: Figure 6: Small bowel wall thickness measured at more than 4 mm (6 mm) with marked and layered wall enhancement Radiology, Hôpital Beaujon - Clichy/FR Page 26 of 36

Fig. 7: Figure 7: Marked and layered small bowel wall enhancement (green arrow) Radiology, Hôpital Beaujon - Clichy/FR Page 27 of 36

Fig. 8: Figure 8: Marked and homogeneous small bowel wall enhancement (green arrow) Radiology, Hôpital Beaujon - Clichy/FR Page 28 of 36

Fig. 9: Figure 9: Atrophic valvulae conniventes Radiology, Hôpital Beaujon - Clichy/FR Page 29 of 36

Fig. 10: Figure 10: Thickened valvulae conniventes Radiology, Hôpital Beaujon - Clichy/FR Page 30 of 36

Fig. 11: Figure 11: Retraction of bowel loops (with angulations, green arrow) Radiology, Hôpital Beaujon - Clichy/FR Page 31 of 36

Fig. 12: Figure 12: Mesentery thickening (green arrow) with adhesion and retraction of bowel loops (yellow arrow) Radiology, Hôpital Beaujon - Clichy/FR Page 32 of 36

Fig. 13: Figure 13: Pattern2, with reduction of distensibility+ marked bowel wall enhancement + layered bowel wall enhancement + bowel wall thickening Radiology, Hôpital Beaujon - Clichy/FR Page 33 of 36

Fig. 14: Figure 14: Combination of the three signs significantly associated with surgery (retraction of bowel loop, homogeneous bowel wall enhancement and atrophic valvulae conniventes) Radiology, Hôpital Beaujon - Clichy/FR Page 34 of 36

Conclusion If there is no pathognomonic radiological finding of chronic radiation enteritis, there are nevertheless several CT findings significantly associated to the disease. The most frequent are reduction of distensibility, marked bowel wall enhancement, extended length disease (more than 20 cm), continuous disease and retraction of bowel loops. Two main CT patterns are evocative of the disease, which are (pattern 1) extended and continuous disease, reduction of distensibility, homogeneous enhancement and retraction of bowel loops, and (pattern 2) reduction of distensibility with layered and marked bowel wall enhancement and thickening bowel wall. Pattern 1 is highly associated with surgery. Page 35 of 36

References 1- Hauer-Jensen M, Denham JW, Andreyev HJ: Radiation enteropathy--pathogenesis, treatment and prevention. Nat Rev GastroenterolHepatol 2014;11:470-479. 2- Harb AH, AbouFadel C, Sharara AI: Radiation enteritis. CurrGastroenterol Rep 2014;16:383. 3- Hernandez-Moreno A, Vidal-Casariego A, Calleja-Fernandez A, Kyriakos G, VillarTaibo R, Urioste-Fondo A, Cano-Rodriguez I, Ballesteros-Pomar MD: Chronic enteritis in patients undergoing pelvic radiotherapy: Prevalence, risk factors and associated complications. NutrHosp 2015;32:2178-2183. 4- Shadad AK, Sullivan FJ, Martin JD, Egan LJ: Gastrointestinal radiation injury: Symptoms, risk factors and mechanisms. World J Gastroenterol 2013;19:185-198. Page 36 of 36