Radiographic Evaluation of Ileal Pouch Disorders: A Systematic Review

BACKGROUND

Radiographic imaging of the abdomen and pelvis plays an important role in the diagnosis and management of ileal pouch disorders with modalities including CT, MRI, contrasted pouchography, and defecography.

OBJECTIVES

To perform a systematic review of the literature and describe applications of cross-sectional imaging, pouchography, defecography, and ultrasonography.

DATA SOURCES

PubMed, Google Scholar, and Cochrane database.

STUDY SELECTION

Relevant articles on endoscopy in ileal pouches published between January 2003 and June 2023 in English were included on the basis of Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

INTERVENTION

Main abdominal and pelvic imaging modalities and their applications in the diagnosis of ileal pouch disorders were included.

MAIN OUTCOME MEASURES

Accuracy in characterization of ileal pouch disorders.

RESULTS

CT is the test of choice for the evaluation of acute anastomotic leaks, perforation, and abscess(es). MRI of the pelvis is suitable for the assessment of chronic anastomotic leaks and their associated fistulas and sinus tracts, as well as for the penetrating phenotype of Crohn's disease of the pouch. CT enterography and magnetic resonance enterography are useful in assessing intraluminal, intramural, and extraluminal disease processes of the pouch and prepouch ileum. Water-soluble contrast pouchography is particularly useful for evaluating acute or chronic anastomotic leaks and outlines the shape and configuration of the pouch. Defecography is the key modality to evaluate structural and functional pouch inlet and outlet obstructions. Ultrasonography can be performed to assess the pouch in experienced IBD centers.

LIMITATIONS

This is a qualitative, not quantitative, review of mainly case series and case reports.

CONCLUSIONS

Abdominopelvic imaging, along with clinical and endoscopic evaluation, is imperative for accurately assessing structural, inflammatory, functional, and neoplastic disorders. See video from symposium .

Ouch, my pouch! a clinician's guide to pouchitis

Pouchitis is defined as inflammation of the ileal pouch created during a restorative proctocolectomy with ileal pouch-anal anastomosis. Although the incidence of this inflammatory condition is high, the exact etiology often remains unclear and the management challenging. In this review, we summarize the clinical presentation, pathogenesis, diagnosis, and management of this common complication.

MR Enterography in Ulcerative Colitis: Beyond Endoscopy

Ulcerative colitis (UC) is a chronic idiopathic inflammatory bowel disease (IBD) that progressively affects mucosa and submuccosa of the colon and rectum in a continual pattern. In comparison, Crohn disease (CD), the other type of IBD, is a chronic transmural inflammatory disorder that can involve any part of the gastrointestinal tract. MR enterography (MRE) has emerged as an important imaging modality for the diagnosis and detection of disease activity and complications in CD, with comparable results to those of endoscopy. But MRE has been underused for assessment of UC in recent years, and clinicians heavily rely on endoscopic findings for management of UC. Despite UC being considered an endoscopically assessable disease, MRE can provide useful information beyond that obtained with endoscopy about mural or extramural abnormalities, inaccessible parts of the colonic lumen, associated extraintestinal diseases, and superimposed pathologic conditions. Moreover, endoscopy might be contraindicated in some clinical settings due to the risk of colonic perforation. In addition to depicting the features of UC activity in different phases, MRE demonstrates findings of disease chronicity that cannot be achieved with endoscopy, particularly in a patient with colitis of unknown cause. The valuable diagnostic role of MRE to exclude undiagnosed CD in patients with UC who have refractory disease or those with postproctocolectomy complications is also emphasized. Radiologists can play a crucial role in the management of UC with MRE by addressing what is beyond endoscopy. ©RSNA, 2023 Test Your Knowledge questions are available in the supplemental material.

A step-by-step guide to ileoanal J-pouch MRI interpretation

BACKGROUND

Multidisciplinary management of patients with an ileoanal pouch requires dedicated imaging to identify structural problems of the pouch associated with dysfunction. The purpose of this study is to provide a framework for interpretation of magnetic resonance imaging (MRI) scan of the ileoanal pouch to enable surgeons and radiologists to work cohesively, optimise diagnosis and ultimately improve patient care.

METHODS

We propose a protocol for structured MRI assessment of the ileal pouch, aiming to provide surgeons a systematic report of the anatomy, its variations and pouch complications. This guide consists of studying the characteristics of the bowel, mesentery and anal canal.

RESULTS

The presented checklist is designed to systematically interpret and identify abnormalities of the ileoanal pouch on MRI. It focuses on the characteristics of the bowel (encompassing pre-pouch ileum, pouch and rectal cuff), mesentery and anal canal. The different elements of the checklist are presented in the associated supplementary video.

CONCLUSIONS

A combination of clinical assessment, endoscopic evaluations and imaging is fundamental to achieving accurate diagnosis of ileoanal pouch surgery complications and pouch dysfunction.

MRI of the ileal pouch

Ileal pouch surgery is the surgical gold standard treatment for patients with ulcerative colitis (UC) and familial adenomatous polyposis (FAP). However, ileal pouch surgery is a technically challenging procedure and is associated with high morbidity. Clinical presentations of pouch complications are often nonspecific but imaging can identify many of these complications and is essential in clinical management. This paper will focus on magnetic resonance imaging (MRI) of the ileal pouch, including recommended MRI protocol and approach to imaging interpretation with an emphasis on those ileal pouch complications particularly well evaluated with MRI.

Disease Monitoring of the Ileoanal Pouch: How to Utilize Biomarkers, Imaging, and Pouchoscopy

PURPOSE OF REVIEW

Restorative proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis has been associated with multiple short- and long-term complications. In this review, we examine the role of biomarkers, imaging, and pouchoscopy in the assessment of patients after ileal pouch-anal anastomosis, with a particular focus on the emergence of novel biomarkers and techniques for evaluating and risk stratifying patients after this procedure in the hopes of improving outcomes in this specific population.

RECENT FINDINGS

There are indications that that the incidence of pouchitis may be increasing in recent decades. Calprotectin and other non-invasive imaging tests such as ultrasound may offer advantages in distinguishing patients with inflammatory conditions of the pouch from other etiologies. In the search for other biomarkers that may identify patients at risk for inflammatory conditions of the pouch, the stool microbiota and metabolomics may play a key role in identifying those patients at greatest risk for complications. Advances in biomarkers, imaging, and standardized pouchoscopy scoring offer immediate improvements in clinical care and will prompt future research efforts.

Defining normal pouch function in patients with ileal pouch-anal anastomosis: a pilot study

BACKGROUND

Most patients experience good functional outcomes following ileal pouch-anal anastomosis (IPAA) for ulcerative colitis.

AIM

We aimed to determine if asymptomatic patients with an IPAA had findings consistent with normal defecation on standard objective anorectal tests.

METHODS

Patients 18-65 years old with IPAA and self-reported healthy pouch function were recruited. Patients with chronic pouchitis, Crohn's disease, anastomotic stricture, or indication for IPAA other than ulcerative or indeterminate colitis were excluded. Patients underwent an interview with an abbreviated Rome Questionnaire followed by high-resolution ano-pouch manometry, balloon expulsion test, pouch barostat, and magnetic resonance (MR) defecography.

RESULTS

Twenty patients completed all testing. Six patients were excluded from the final analysis due to symptoms suggestive of pouch evacuation disorder on the abbreviated Rome Questionnaire (n = 2), structural abnormality on MR imaging (n = 3), or both (n = 1). Of the remaining 14 patients, mean anal resting pressure during high-resolution manometry was 72 ± 16 mmHg, mean anal squeeze pressure was 247 ± 69 mmHg, and mean pouch-anal gradient during the simulated evacuation was -27 ± 37 mmHg. The meantime to balloon expulsion was 54 seconds. During dynamic MR defecography, the mean descent of ano-pouch junction was 2.6 cm, and mean pouch evacuation was 44.5% and 74.2% pre- and posttoilet phase, respectively.

CONCLUSIONS

A substantial proportion of patients with IPAA and self-reported healthy pouch function have anatomic and/or functional abnormalities of the pouch. In asymptomatic IPAA patients with an anatomically normal pouch, we have proposed normal parameters for high-resolution ano-pouch manometry, time to balloon expulsion, pouch barostat, and MR defecography.

ACR Appropriateness Criteria® Anorectal Disease

This review summarizes the relevant literature for the selection of the initial imaging in 4 clinical scenarios in patients with suspected inflammatory disease or postoperative complication of the anorectum. These clinical scenarios include suspected perianal fistula or abscess; rectovesicular or rectovaginal fistula; proctitis or pouchitis; and suspected complication following proctectomy, coloproctectomy, or colectomy with a pouch or other anastomosis. The appropriateness of imaging modalities as they apply to each clinical scenario is rated as usually appropriate, may be appropriate, and usually not appropriate to assist the selection of the most appropriate imaging modality in the corresponding clinical scenarios of anorectal disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Successful Closure of the Tip of the "J" Fistula of the Ileal Pouch With Double Over-the-Scope Clips

Ileal pouch-anal anastomosis is the surgical procedure of choice for patients who require colectomy for complicated ulcerative colitis with or without associated dysplasia and familial adenomatous polyposis. Leaks from the suture lines or anastomosis can lead to pouch failure. Treatment options have been radiographic drainage and surgical intervention. Endoscopic therapy has emerged a viable nonsurgical treatment option for some of the complications associated with J-pouch surgery. Here, we present a case of endoscopic management of a leak from the tip of the J-pouch with sequential application of 2 over-the-scope clips.

Physical and Metabolic Changes after Ileal Pouch-Anal Anastomosis: A Case Study

This case study examined changes in body composition, resting metabolic rate (RMR), aerobic capacity, and daily physical activity in a patient who had ulcerative colitis and underwent ileal pouch-anal anastomosis (IPAA) surgery. Body composition, RMR, and peak oxygen consumption (VO₂peak) were assessed prior to surgery and four, eight, and 16 weeks after IPAA surgery. Daily physical activity data were extracted from a wrist-worn activity tracker preoperatively and 16 months postoperatively. At baseline, total body mass was 95.3 kg; body fat, 11.6%; lean body mass, 81.1 kg; RMR, 2416 kcal/d; and VO₂peak, 42.7 mL/kg/min. All values decreased from baseline at four weeks postoperatively, body mass was 85.2 kg (-10.5%); body fat, 10.9% (-6.0%); lean body mass, 73.1 kg (-9.9%); RMR 2210 kcal/d (-8.5%) and VO₂peak, 25.5 mL/kg/min (-40.3%). At 16 weeks postoperatively, most parameters were near their baseline levels (within 1-7%), exceptions were VO₂peak, which was 20.4% below baseline, and RMR, which increased to nearly 20% above baseline. After the patient had IPAA surgery, his total and lean body masses, RMR, and aerobic capacity were markedly decreased. Daily physical activity decreased postoperatively and likely contributed to the decreased aerobic capacity, which may take longer to recover compared to body composition and RMR parameters.

Reporting Templates for MRI and Water-Soluble Contrast Enema in Patients With Ileal Pouch-Anal Anastomosis: Experience From a Large Referral Center

Ileal pouch-anal anastomosis (IPAA) surgery is the reference standard surgical procedure for treatment of ulcerative colitis and most patients with familial adenomatous polyposis. This procedure allows preservation of fecal continence and gastrointestinal continuity. However, it is associated with a wide variety of complications, which often have nonspecific and overlapping clinical presentations, making imaging an important part of workup for pouch dysfunction. The purpose of this article is to propose structured reporting templates for MRI and water-soluble contrast enema (WSCE), based on our referral pouch center's experience, in patients who have undergone IPAA surgery. We review salient surgical technique, pouch anatomy, and imaging protocols, with an emphasis on a systematic search pattern for evaluation of ileal pouch complications using proposed structured reporting templates for MRI and WSCE.

Imaging of Abdominal Postoperative Complications

We present a case-based review of abdominal postoperative complications, organized by organ system affected, including wound/superficial, hepatobiliary, pancreatic, gastrointestinal, genitourinary, and vascular complications. Both general complications and specific considerations for certain types of operations are described, as well as potential pitfalls that can be confused with complications. Representative cases are shown using all relevant imaging modalities, including CT, fluoroscopy, ultrasound, MRI, and nuclear medicine. Management options are also described, highlighting those that require radiologist input or intervention.

Lower fecal pH may be a novel indicator of pouchitis after IPAA in patients with FAP or metachronous Lynch syndrome

BACKGROUND AND OBJECTIVES

To assess whether fecal pH might be an indicator of pouchitis during the postoperative period in hereditary colorectal cancer (CRC) patients who have undergone ileal pouch anal anastomosis (IPAA).

METHODS

Five consecutive daily pH values of stool samples from 31 familial adenomatous polyposis (FAP) patients and 32 metachronous Lynch syndrome patients who underwent IPAA procedures were reviewed. Patients with pouchitis (pouchitis group, n = 22) were compared with patients without pouchitis (nonpouchitis group, n = 41). A receiver operating characteristic (ROC) analysis was performed to determine the indicative potential of fecal pH for pouchitis. A Mantel-Cox test was also performed to evaluate the survival status of patients with or without pouchitis.

RESULTS

Pouchitis was noted in 22 (34.9%) of 63 patients after IPAA. The significance of each daily average fecal pH value and the 5-day overall average fecal pH value was compared between the two groups (P < .01). A cutoff fecal pH value of 7.46 was determined by the ROC analysis for assessing the risk of pouchitis. No significant difference in 5-year overall survival was observed between the two groups.

CONCLUSION

A lower fecal pH value in patients with hereditary CRC after IPAA might be a new indicator of pouchitis.