Test Characteristics of Cross-sectional Imaging and Concordance With Endoscopy in Postoperative Crohn's Disease

Endoscopic Assessment of Postoperative Recurrence in Crohn's Disease: Evolving Concepts

Endoscopic assessment within 6 to 12 months of ileocolonic resection has been the mainstay of management of postoperative Crohn's disease. The original Rutgeerts score to grade endoscopic recurrence was designed for predicting prognosis after resection. However, it is increasingly recognized that the clinical course of disease varied based on anatomic location of lesion rather than only severity of endoscopic lesions. It is also important to recognize several anatomic landmarks around surgical anastomosis, given the vast technical modifications in surgical technique over the past few decades. It is important to understand the changing paradigm of assessing endoscopic recurrence as it considerably influences subsequent therapeutic management.

Computed tomography enterography radiomics and machine learning for identification of Crohn's disease

BACKGROUND

Crohn's disease is a severe chronic and relapsing inflammatory bowel disease. Although contrast-enhanced computed tomography enterography is commonly used to evaluate crohn's disease, its imaging findings are often nonspecific and can overlap with other bowel diseases. Recent studies have explored the application of radiomics-based machine learning algorithms to aid in the diagnosis of medical images. This study aims to develop a non-invasive method for detecting bowel lesions associated with Crohn's disease using CT enterography radiomics and machine learning algorithms.

METHODS

A total of 139 patients with pathologically confirmed Crohn's disease were retrospectively enrolled in this study. Radiomics features were extracted from both arterial- and venous-phase CT enterography images, representing both bowel lesions with Crohn's disease and segments of normal bowel. A machine learning classification system was constructed by combining six selected radiomics features with eight classification algorithms. The models were trained using leave-one-out cross-validation and evaluated for accuracy.

RESULTS

The classification model demonstrated robust performance and high accuracy, with an area under the curve of 0.938 and 0.961 for the arterial- and venous-phase images, respectively. The model achieved an accuracy of 0.938 for arterial-phase images and 0.961 for venous-phase images.

CONCLUSIONS

This study successfully identified a radiomics machine learning method that effectively differentiates Crohn's disease bowel lesions from normal bowel segments. Further studies with larger sample sizes and external cohorts are needed to validate these findings.

Diagnostic value of MR and CT enterography in post-operative recurrence of Crohn's disease: a systematic review and meta-analysis

Post-operative recurrence is a critical issue in the surveillance of Crohn's disease after ileocecal resection. This meta-analysis aims to assess the diagnostic yield of enterography techniques in post-operative recurrence of Crohn's disease. A systematic electronic bibliographic databases search was conducted. The inclusion criteria of original articles were: Utilized MR enterography or CT enterography after ileocolonic resection; Documented recurrence by ileo-colonoscopy (Rutgeerts' score ≥ i2); Provided crude data of diagnostic performance. A random-effect method was used for analysis. Relative risk and diagnostic value of each imaging feature were calculated. Eleven studies (11 populations and 589 patients) were included (4 CTE and 7 MRE with 248 and 341 patients, respectively). The pooled sensitivity and specificity of the enterography were 91% (95% CI: 0.85-0.95) and 75% (95% CI: 0.56-0.87), respectively. The pooled sensitivity and specificity of CTE were 93% (95% CI: 0.87-0.96) and 67% (95% CI: 0.35-0.90), respectively. MRE revealed pooled sensitivity and specificity of 90% (95% CI: 0.78-0.96) and 78% (95% CI: 0.57-0.90), respectively. The inter-study heterogeneity was low for sensitivity (I2 = 29%, p-value = 0.17) and high for specificity (I2 = 85%, p-value < 0.01). Wall enhancement, anastomosis wall thickening, anastomosis stenosis, pre-anastomotic dilatation, penetrating lesion, comb sign, and perivisceral edema were significantly higher in POR patients. Wall thickening and penetrating lesion were the most sensitive (81%) and specific (97%) findings, respectively. MRE and CTE exhibit high sensitivity and acceptable specificity (especially MRE) for detection of recurrence in Crohn's disease which makes them an effective initial screening tool and reserves ileo-colonoscopy for those patients with inconclusive enterography results.

Evidence-Based Review of Current Cross-Sectional Imaging of Inflammatory Bowel Disease

CT and MR enterography are cross-sectional imaging examinations used in the assessment of inflammatory bowel disease. Consistent reporting and standardized nomenclature are important for clear communication with referring clinicians. Enterography has not only been used to depict inflammation in the small bowel, but it has also been used to quantify disease activity, assess distribution of disease, and detect complications including penetrating disease. This article reviews cross-sectional imaging findings in inflammatory bowel disease, including the current literature focusing on small bowel Crohn's disease and ulcerative colitis, with evidence-based guidelines on appropriate protocols and imaging procedures.

Histologic Activity From Neoterminal Ileal Biopsies in Patients With Crohn's Disease in Endoscopic Remission is Associated With Postoperative Recurrence

INTRODUCTION

Following ileocolic resection (ICR), the clinical importance and prognostic implications of histologic activity on biopsies in Crohn's disease (CD) patients with endoscopic remission are not well defined. The aim of this study was to determine if histologic activity in patients with endoscopic remission is associated with future risk of endoscopic and/or radiologic postoperative recurrence (POR).

METHODS

In this multicenter retrospective cohort study, adult patients with CD who underwent ICR between 2009 and 2020 with endoscopic biopsies of ileal mucosa from Rutgeerts i0 on index colonoscopy were included. The composite rate of endoscopic (Rutgeerts score ≥i2b) and radiologic (active inflammation on imaging) recurrence was compared in patients with and without histologic activity using a Kaplan-Meier survival analysis. A multivariable Cox proportional hazard regression model including clinically relevant risk factors of POR, postoperative biologic prophylaxis, and histology activity was designed.

RESULTS

A total of 113 patients with i0 disease on index colonoscopy after ICR were included. Of these, 42% had histologic activity. Time to POR was significantly earlier in the histologically active versus normal group ( P = 0.04). After adjusting for clinical risk factors of POR, histologic activity (HR 2.37, 95% CI 1.17-4.79; P = 0.02) and active smoking (HR 2.54, 95% CI 1.02-6.33; P = 0.05) were independently associated with subsequent composite POR risk.

DISCUSSION

In patients with postoperative CD, histologic activity despite complete endoscopic remission is associated with composite, endoscopic, and radiographic recurrence. Further understanding of the role of histologic activity in patients with Rutgeerts i0 disease may provide a novel target to reduce disease recurrence in this population.

Postoperative Crohn's Disease Recurrence Risk and Optimal Biologic Timing After Temporary Diversion Following Ileocolic Resection

BACKGROUND

Postoperative recurrence of Crohn's disease (CD) is common. While most patients undergo resection with undiverted anastomosis (UA), some individuals also have creation of an intended temporary diversion (ITD) with an ileostomy followed by ostomy takedown (OT) due to increased risk of anastomotic complications. We assessed the association of diversion with subsequent CD recurrence risk and the influence of biologic prophylaxis timing to prevent recurrence in this population.

METHODS

This was a retrospective cohort study of CD patients who underwent ileocolic resection between 2009 and 2020 at a large quaternary health system. Patients were grouped by continuity status after index resection (primary anastomosis or ITD). The outcomes of the study were radiographic, endoscopic, and surgical recurrence as well as composite recurrence postoperatively (after OT in the ITD group). Propensity score-weighted matching was performed based on risk factors for diversion and recurrence. Multivariable regression and a Cox proportional hazards model adjusting for recurrence risk factors were used to assess association with outcomes. Subgroup analysis in the ITD group was performed to assess the impact of biologic timing relative to OT (no biologic, biologic before OT, after OT) on composite recurrence.

RESULTS

A total of 793 CD patients were included (mean age 38 years, body mass index 23.7 kg/m2, 52% female, 23% active smoker, 50% penetrating disease). Primary anastomosis was performed in 67.5% (n = 535) and ITD in 32.5% (n = 258; 79% loop, 21% end) of patients. Diverted patients were more likely to have been males and to have had penetrating and perianal disease, prior biologic use, lower body mass index, and lower preoperative hemoglobin and albumin (all P < .01). After a median follow-up of 44 months, postoperative recurrence was identified in 83.3% patients (radiographic 40.4%, endoscopic 39.5%, surgical 13.3%). After propensity score matching and adjusting for recurrence risk factors, no significant differences were seen between continuity groups in radiographic (adjusted hazard ratio [aHR], 1.32; 95% confidence interval [CI], 0.91-1.91) or endoscopic recurrence (aHR, 1.196; 95% CI, 0.84-1.73), but an increased risk of surgical recurrence was noted in the ITD group (aHR, 1.61; 95% CI, 1.02-2.54). Most (56.1%) ITD patients started biologic prophylaxis after OT, 11.4% before OT, and 32.4% had no postoperative biologic prophylaxis. Biologic prophylaxis in ITD was associated with younger age (P < .001), perianal disease (P = .04), and prior biologic use (P < .001) but not in recurrence (P = .12). Despite higher rates of objective disease activity identified before OT, biologic exposure before OT was not associated with a significant reduction in composite post-OT recurrence compared with starting a biologic after OT (52% vs 70.7%; P = 0.09).

CONCLUSIONS

Diversion of an ileocolic resection is not consistently associated with a risk of postoperative recurrence and should be performed when clinically appropriate. Patients requiring diversion at time of ileocolic resection are at high risk for recurrence, and biologic initiation prior to stoma reversal may be considered.

Crohn's disease

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract that might lead to progressive bowel damage and disability. The exact cause of Crohn's disease is unknown, but evidence points towards multifactorial events causing dysregulation of the innate immune system in genetically susceptible people. Commonly affecting the terminal ileum and proximal colon, Crohn's disease inflammation is often discontinuous and patchy, segmental, and transmural. Identification of characteristic findings on ileocolonoscopy and histology remains the diagnostic gold standard, but complete assessment involves laboratory abnormalities, including micronutrient deficiencies, cross-sectional imaging to identify transmural disease extent, severity and complications, and a psychosocial assessment. Treatment strategies for patients with Crohn's disease now go beyond achieving clinical remission to include deeper targets of endoscopic healing and consideration of adjunctive histological and transmural targets to alter disease progression potentially further. The use of early effective advanced therapies and development of therapies targeting alternative novel pathways with improved safety profiles have resulted in a new era of healing in Crohn's disease management. Future combination of advanced therapies with diet or other biological drugs and small molecules, together with improvements in tight control monitoring tools and predictive biomarkers might continue to improve outcomes for patients with Crohn's disease.

Results of the Eighth Scientific Workshop of ECCO: Diagnosing Postoperative Recurrence of Crohn's Disease After an Ileocolonic Resection With Ileocolonic Anastomosis

Despite the introduction of potent biologic therapies, many patients with Crohn's disease [CD] still require an ileocolonic resection [ICR] during the course of their disease. Furthermore, the need of redo ICR has not decreased over the past few decades, highlighting the need for better strategies to prevent and treat postoperative recurrence [POR]. The first step to develop such a strategy would be to define and standardise the description of POR with adequate diagnostic instruments. In this article, we will describe the different methodologies used to report POR [endoscopic, histological, radiological, biochemical, clinical, and surgical], and review their potential benefits and limitations, as well as the optimal timing of evaluation.

Small bowel imaging in inflammatory bowel disease: updates for 2023

INTRODUCTION

Cross-sectional imaging techniques including MR and CT enterography and ultrasound are integral to Crohn's disease management, accurate, responsive, and well tolerated. They assess the full thickness of the bowel wall, perienteric environment, and distant complications. As we strive toward tighter disease control, imaging's role will expand further with transmural healing becoming an increasingly important therapeutic target.

AREAS COVERED

MEDLINE and Web of Science were searched from 2012 to 2023 inclusive. We review the evidence for cross-sectional imaging in assessing disease activity, phenotyping, and therapeutic response assessment. Emerging novel imaging applications such as quantifying enteric motility and fibrosis, prognostication, and potential utility of artificial intelligence will be covered. Recent international consensus statements highlight the need for standardized imaging reporting and definitions of transmural healing and remission. We will discuss how recent advances may be best integrated into patient care and highlight key outstanding research questions.

EXPERT OPINION

Cross-sectional imaging is established in Crohn's disease management. Research emphasis should be placed on optimal integration of imaging modalities in clinical care pathways, workforce training, definitions, and evidence for use of imaging based therapeutic targets such as transmural healing, better phenotyping of stricturing disease, and developing novel techniques, including integration of artificial intelligence.

Intestinal ultrasound as a non-invasive tool to monitor inflammatory bowel disease activity and guide clinical decision making

Intestinal ultrasound (IUS) is a non-invasive, real-time, cross-sectional imaging tool that can be used at the point-of-care to assess disease activity in patients with Crohn’s disease or ulcerative colitis. IUS promotes quick and impactful treatment decisions that can modify disease progression and enhance patient compliance. This review will summarize the technical aspects of IUS, the evidence to support the use of IUS in disease activity monitoring, the comparison of IUS to current standard of care monitoring modalities such as colonoscopy and calprotectin, and the optimal positioning of IUS in a tight-control monitoring strategy.

Replacing Endoscopy with Magnetic Resonance Enterography for Mucosal Activity Assessment in Terminal Ileal Crohn’s Disease: Are We There Yet?

Crohn’s disease (CD) is a chronic immune mediated disorder that most commonly affects the small bowel and/or the large bowel. Treatment targets in CD include mucosal healing assessed via ileocolonoscopy and transmural healing assessed through cross-sectional imaging modalities such as magnetic resonance enterography (MRE). More recently, histological healing in CD has emerged as a treatment target, though it is made cumbersome given its reliance on frequent endoscopic examinations. With expert guidelines now recommending regular objective assessments as part of a treat-to-target approach, accurate non-invasive assessment will become increasingly critical. MRE has an established role in the assessment of small bowel CD, with growing data supportive of its ability in detecting disease activity at mucosal and histological levels. This could therefore potentially reduce the need for serial endoscopic assessment. Thus, this review will assess the capacity of individual MRE parameters and MRE indices for detecting mucosal and histological small bowel CD activity. Furthermore, challenging scenarios, such as CD activity detection in post-operative clinical scenarios and abnormal findings in the context of a normal ileocolonoscopy, will be explored.

Contemporary Management of Postoperative Crohn's Disease after Ileocolonic Resection

Surgery remains an important treatment modality in the multidisciplinary management of patients with Crohn's disease (CD). To illustrate the recent advances in the management of postoperative CD we outline the contemporary approach to treatment: diagnosing disease recurrence using endoscopy or noninvasive methods and risk stratification underlying decisions to institute treatment. Endoscopic scoring indices are being refined to guide treatment decisions by accurately estimating the risk of recurrence based on endoscopic appearance. The original Rutgeerts score has been modified to separate anastomotic lesions from lesions in the neoterminal ileum. Two further indices, the REMIND score and the POCER index, were recently developed with the same intention. Noninvasive monitoring for recurrence using a method with high negative predictive value has the potential to simplify management algorithms and only perform ileocolonoscopy in a subset of patients. Fecal calprotectin, intestinal ultrasound, and magnetic resonance enterography are all being evaluated for this purpose. The use of infliximab for the prevention of postoperative recurrence is well supported by data, but management decisions are fraught with uncertainty for patients with previous exposure to biologics. Data on the use of ustekinumab and vedolizumab for postoperative CD are emerging, but controlled studies are lacking.

Crohn's disease active inflammation assessment with iodine density from dual-energy CT enterography: comparison with endoscopy and conventional interpretation

PURPOSE

To compare terminal ileum (TI) mucosal iodine density obtained at dual-energy CT enterography (DECTE) with conventional CT interpretation and endoscopy in patients with Crohn's disease (CD).

MATERIALS AND METHODS

Twenty-three CD patients (14 men; mean[SD] age:48.1[16.7] years) with endoscopy within 30 days of DECTE were retrospectively identified. An inflammatory bowel disease gastroenterologist reviewed endoscopic images. Two radiologists qualitatively assessed the presence of active TI inflammation. Mean iodine density normalized to the aorta (I%), mean absolute iodine density (I), and iodine density standard deviation (I_SD) from the distal 2 cm ileum (TI) mucosa obtained using semiautomatic prototype software were compared with endoscopic assessment using Mann Whitney tests. The optimal threshold I% and I were determined from receiver operating curves (ROC). Sensitivity and specificity of conventional interpretation and determined iodine thresholds were compared using McNemar's test. Inter-reader agreement was assessed using kappa. A p < 0.05 indicated statistical significance.

RESULTS

Twelve (52.1%) patients had endoscopic active inflammation. I% was 37.9[13.3]% for patients with and 21.7[7.5]% for patients without endoscopic active inflammation (p = 0.001). The optimal ROC threshold 24.6% had 100% sensitivity and 81.8% specificity (AUC = 0.909, 95% CI 0.777-1). I was 2.44[0.73]mg/mL for patients with and 1.77[1.00]mg/mL for patients without active endoscopic inflammation (p = 0.0455). The optimal ROC threshold 1.78 mg/mL I had 91.7% sensitivity and 63.6% specificity (AUC = 0.75, 95% CI 0.532-0.968). I_SD was similar for patients with and without endoscopic active inflammation (0.82[0.33]mg/mL and 0.77[0.28]mg/mL, respectively, p = 0.37). Conventional interpretation sensitivity and specificity (R1/R2) were 83.3%/91.7% and 72.7%/54.5%, respectively (all p > 0.05) with moderate inter-reader agreement (Κ = 0.542[95% CI 0.0202-0.088]).

CONCLUSION

Mean normalized iodine density is highly sensitive and specific for endoscopic active inflammation. DECTE could be considered as a surrogate to endoscopy in CD patients. Despite trends towards improved sensitivity and specificity compared with conventional interpretation, future larger studies are needed.

Early Initiation of Antitumor Necrosis Factor Therapy Reduces Postoperative Recurrence of Crohn's Disease Following Ileocecal Resection

BACKGROUND

Postoperative recurrence (POR) of Crohn's disease (CD) is common after surgical resection. We aimed to compare biologic type and timing for preventing POR in adult CD patients after ileocecal resection (ICR).

METHODS

We performed a retrospective cohort study of CD patients who underwent an ICR at 2 medical centers. Recurrence was defined by endoscopy (≥ i2b Rutgeerts score) or radiography (active inflammation in neoterminal ileum) and stratified by type and timing of postoperative prophylactic biologic within 12 weeks following an ICR (none, tumor necrosis factor antagonists [anti-TNF], vedolizumab, and ustekinumab).

RESULTS

We identified 1037 patients with CD who underwent an ICR. Of 278 (26%) who received postoperative prophylaxis, 80% were placed on an anti-TNF agent (n = 223) followed by ustekinumab (n = 28, 10%) and vedolizumab (n = 27, 10%). Prophylaxis was initiated in 35% within 4 weeks following an ICR and in 65% within 4 to 12 weeks. After adjusting for factors associated with POR, compared with no biologic prophylaxis, the initiation of an anti-TNF agent within 4 weeks following an ICR was associated with a reduction in POR (adjusted hazard ratio, 0.61; 95% CI, 0.40-0.93). Prophylaxis after 4 weeks following an ICR or with vedolizumab or ustekinumab was not associated with a reduction in POR compared with those who did not receive prophylaxis.

CONCLUSION

Early initiation of an anti-TNF agent within 4 weeks following an ICR was associated with a reduction in POR. Vedolizumab or ustekinumab, at any time following surgery, was not associated with a reduction in POR, although sample size was limited.