Diffusion-weighted magnetic resonance enterography for prediction of response to tumor necrosis factor inhibitors in stricturing Crohn's disease

Deep learning in magnetic resonance enterography for Crohn's disease assessment: a systematic review

Crohn's disease (CD) poses significant morbidity, underscoring the need for effective, non-invasive inflammatory assessment using magnetic resonance enterography (MRE). This literature review evaluates recent publications on the role of deep learning in improving MRE for CD assessment. We searched MEDLINE/PUBMED for studies that reported the use of deep learning algorithms for assessment of CD activity. The study was conducted according to the PRISMA guidelines. The risk of bias was evaluated using the QUADAS-2 tool. Five eligible studies, encompassing 468 subjects, were identified. Our study suggests that diverse deep learning applications, including image quality enhancement, bowel segmentation for disease burden quantification, and 3D reconstruction for surgical planning are useful and promising for CD assessment. However, most of the studies are preliminary, retrospective studies, and have a high risk of bias in at least one category. Future research is needed to assess how deep learning can impact CD patient diagnostics, particularly when considering the increasing integration of such models into hospital systems.

Predicting Treatment Response in Inflammatory Bowel Diseases: Cross-Sectional Imaging Markers

Therapeutic options for inflammatory bowel diseases (IBD) have largely expanded in the last decades, both in Crohn's disease and ulcerative colitis, including multiple biological drugs targeting different inflammation pathways. However, choosing the best treatment and timing for each patient is still an undeniable challenge for IBD physicians due to the marked heterogeneity among patients and disease behavior. Therefore, early prediction of the response to biological drugs becomes of utmost importance, allowing prompt optimization of therapeutic strategies and thus paving the way towards precision medicine. In such a context, researchers have recently focused on cross-sectional imaging techniques (intestinal ultrasound, computed tomography, and magnetic resonance enterography) in order to identify predictive markers of response or non-response to biologic therapies. In this review, we aim to summarize data about imaging factors that may early predict disease behavior during biological treatment, potentially helping to define more precise and patient-tailored strategies.

Infliximab response associates with radiologic findings in bio-naïve Crohn's disease

OBJECTIVES

Since a reliable model for predicting infliximab (IFX) benefits in bio-naïve Crohn's disease (CD) is still lacking, we constructed a magnetic resonance enterography (MRE)-based model to predict the risk of loss of response to IFX in bio-naïve patients with CD.

METHODS

This retrospective multicenter study enrolled 188 bio-naïve patients with CD who underwent MRE before IFX therapy. Therapeutic outcomes were determined based on clinical symptoms and endoscopic findings within 52 weeks. The areas of bowel wall segmentation were decided by two experienced radiologists in consensus. Texture features were extracted using the least absolute shrinkage and selection operator, and a radiomic model was built using multivariate logistic regression. The model performance was validated by receiver operating characteristic, calibration curve, and decision curve analysis.

RESULTS

The area under the curve of radiomic model was 0.88 (95% confidence interval: 0.82-0.95), and the model provided clinical net benefit in identifying the loss of response to IFX and exhibited remarkable robustness among centers, scanners, and disease characteristics. The high-risk patients defined by the radiomic model were more likely to develop IFX nonresponse than low-risk patients (all p < 0.05).

CONCLUSIONS

This novel pretreatment MRE-based model could act as an effective tool for the early estimation of loss of response to IFX in bio-naïve patients with CD.

KEY POINTS

• Magnetic resonance enterography model guides infliximab therapy in Crohn's disease. • The model presented significant discrimination and provided net clinical benefit. • Model divided patients into low- and high-risk groups for infliximab failure.

Precision medicine and drug optimization in adult inflammatory bowel disease patients

Inflammatory bowel diseases (IBD) encompass two main entities including ulcerative colitis and Crohn's disease. Although having a common global pathophysiological mechanism, IBD patients are characterized by a significant interindividual heterogeneity and may differ by their disease type, disease locations, disease behaviours, disease manifestations, disease course as well as treatment needs. Indeed, although the therapeutic armamentarium for these diseases has expanded rapidly in recent years, a proportion of patients remains with a suboptimal response to medical treatment due to primary non-response, secondary loss of response or intolerance to currently available drugs. Identifying, prior to treatment initiation, which patients are likely to respond to a specific drug would improve the disease management, avoid unnecessary side effects and reduce the healthcare expenses. Precision medicine classifies individuals into subpopulations according to clinical and molecular characteristics with the objective to tailor preventative and therapeutic interventions to the characteristics of each patient. Interventions would thus be performed only on those who will benefit, sparing side effects and expense for those who will not. This review aims to summarize clinical factors, biomarkers (genetic, transcriptomic, proteomic, metabolic, radiomic or from the microbiota) and tools that could predict disease progression to guide towards a step-up or top-down strategy. Predictive factors of response or non-response to treatment will then be reviewed, followed by a discussion about the optimal dose of drug required for patients. The time at which these treatments should be administered (or rather can be stopped in case of a deep remission or in the aftermath of a surgery) will also be addressed. IBD remain biologically complex, with multifactorial etiopathology, clinical heterogeneity as well as temporal and therapeutic variabilities, which makes precision medicine especially challenging in this area. Although applied for many years in oncology, it remains an unmet medical need in IBD.

Monotherapy with thiopurines in stricturing Crohn's disease: A real-life experience from low- and middle-income countries

BACKGROUND

Stricturing Crohn's disease (CD) is difficult to manage medically with limited treatment options, anti-tumor necrosis factor (TNF) therapy being the first-line therapy. Although thiopurines are also recommended first-line treatment option for maintenance of remission in steroid-dependent CD, evidence on their use in stricturing CD is lacking. We evaluated the efficacy of azathioprine (AZA) in patients with stricturing CD.

METHODS

In this retrospective cohort study (January 2005 to July 2020), patients with stricturing CD who were managed with AZA as a primary therapy for at least 6 months, and had a follow-up of at least 6 months after AZA initiation were included. Disease characteristics, complications, long-term response, and adverse events were noted.

RESULTS

One hundred and fifteen patients were included (mean age 33.8±14 years, 67.8% males, median disease duration 98 months [IQR: 60-158], median follow-up duration 60 months [IQR: 50-96]). 46.1% (n=53) patients had significant anemia at presentation, and 73% (n=84) had isolated small bowel involvement. Median dose of AZA was 100 mg (equivalent to 1.5 mg/kg). Median therapy and follow-up duration (after AZA initiation) was 17 (IQR: 9-42) and 33 months (IQR 18-60), respectively. The cumulative probability of maintaining response without treatment failure at 1, 2, and 5 years was 73.1%, 40.7%, and 18.5%, respectively. Among patients with AZA failure, 15.6% received methotrexate, 13% received anti-TNFs, and 9.5% underwent surgery. Significant anemia (&lt;10 g/dL) at presentation and steroid dependence predicted AZA failure. 31.3% patients experienced adverse events, commonest being leukopenia (n=29, 25.2%).

CONCLUSION

Azathioprine demonstrated good short-term and modest long-term response rates in patients with stricturing CD.

Surgery versus Medical Therapy in Luminal Ileocecal Crohn's Disease

The deeper understanding of the inflammatory process which gradually evolves into irreversible fibrosis and tissue damage has provided a precise picture of the disease course of luminal ileocecal Crohn's disease. According to the model of progressive structural damage, ideal time windows for medical and surgical treatment have been identified. While complicated disease clearly profits from surgical treatment, uncomplicated disease has become, in the last years, the most debatable setting in terms of different approaches including early surgery. On one hand, the rationale of traditional escalating medical therapy (step-up approach) has been undermined by the top-down medical approach. Indeed, the step-up approach has the possible drawback of delaying, up to a later disease stage, the use of more effective agents such as anti-tumor necrosis factors. Conversely, the top-down approach might expose patients to an overtreatment along with side effects including hypersensitivity to biologic agents. More recently, it has been shown how early surgery could be a valid option in this subset of patients being more cost-effective than medical therapy. Involving the surgeon at an early stage is considered now a good clinical practice and, in this scenario full of possibilities, the surgeon should be included into the decision-making process from the very beginning of patient management.

Magnetic resonance enterography in Crohn's disease patients: current state of the art and future perspectives

INTRODUCTION

Crohn's disease (CD) is a major concern due to relatively high incidence and major complications like stricture or fistulas, often requiring surgical treatment. In recent years, magnetic resonance enterography (MRE) became a popular method of diagnosis and disease surveillance. The purpose of this review is to summarize and discuss the major and most recent advances in various aspects of MRE usage in diagnosong Crohn's disease, and to discuss advances in technique, disease activity monitoring and response to treatment.

METHODS

A literature search was performed and relevant publications were included, with emphasis on articles from the past decade.

AREAS COVERED

In this review we have presented articles with major advances in the field of MRE of CD patients such as proper sequence selection, recent advances in scoring of disease activity, differentiation between inflammation and fibrosis, response to treatment and technological advances such as the use of AI.

EXPERT OPINION

The main goal in improving MRE performance will be sequence selection aimed at differenting between inflammation and stricture while shortening the study length adjusted to patient compliance, and developing a standardized scoring system for MRE reporting assisted by artificial intelligence.

Real world analysis on the efficacy and safety of anti-tumor necrosis factor therapy in patients with stricturing Crohn's disease

Crohn’s disease (CD) is often complicated by strictures and associated with increased risk for surgery. Inflammatory strictures respond to medical therapy, and anti-tumor necrosis factor (TNF) therapy is often used after the failure of steroids. However, data on efficacy of anti-TNF therapy in stricturing CD is limited. We retrospectively analysed the records of patients with stricturing CD who were treated with anti-TNF therapy and were prospectively followed from January 2005 to July 2020. Treatment success was defined as continuation of anti-TNF without the requirement for steroids or parenteral nutrition, switch to other anti-TNF, endoscopic dilation, surgery and severe adverse events leading to the withdrawal of anti-TNF. Fifty-nine patients were included [50-infliximab, 9-adalimumab; mean age-30.1 ± 15 years; males-69.5%; median disease duration-124 (range 30–396) months; median follow-up duration-42 (range 8–180) months]. Ileum was the most common site of stricture (69.5%), 20.3% of patients had colonic strictures, and 64.4% had multiple strictures. 55.9% of patients were steroid dependent and 37.3% were steroid refractory. The median duration of anti-TNF therapy was 14 (range 2–96) months, and 54.2% (n = 32) patients received concomitant immunomodulators. 88% improved with induction (11.8% primary non-response), secondary loss of response was seen in 52.2%, and the cumulative probability of treatment success at 1, 2 and 5 years was 69%, 51%, and 28% respectively. Anaemia at presentation predicted poor response. Only 30% of patients retained biologics on long-term (lack of response, cost, adverse events). 16.9% had adverse events, the commonest being reactivation of tuberculosis (5.1%). Anti-TNF therapy is associated with good short-term treatment success with modest long-term response in stricturing CD.

Efficacy of drug and endoscopic treatment of Crohn's disease strictures: A systematic review

BACKGROUND AND AIMS

Strictures are the commonest complication in Crohn's disease. Surgery and endoscopic dilation are the mainstays of treatment, while drug therapy has often been considered contraindicated. The benefit of nonsurgical treatments, particularly drug and endoscopic therapy, need to be defined.

METHODS

Ovid MEDLINE, Embase, Emcare, PsycINFO, CINAHL and the Cochrane Library (inception until August 30, 2019) were searched. Studies with ≥ 10 patients with Crohn's disease strictures, reporting on outcomes following medication or endoscopic treatment, were included.

RESULTS

Of 3480 records, 85 studies met inclusion criteria and formed the basis of this analysis. Twenty-five studies assessed drug therapy; none were randomized trials. Despite study heterogeneity anti-tumor necrosis factor (TNF) therapy appeared effective, with 50% of patients avoiding surgery after 4 years of follow up. No other drug therapy was of demonstrable benefit. Sixty studies assessed endoscopic therapy including 56 on endoscopic balloon dilation, two assessed needle knife stricturotomy, and two stent insertion. Dilation was equally effective for de novo and anastomotic strictures ≤ 5 cm in length, with most studies reporting a subsequent surgical rate of 30% to 50%. Repeat dilation was required in approximately half of all patients.

CONCLUSIONS

Anti-TNF drug therapy and endoscopic balloon dilation are effective strategies for avoiding surgery in patients with stricturing Crohn's disease. Additional endoscopic therapies require further evaluation. Early data suggest that combining these therapies may provide greater benefit than individual therapies. Optimization of current drug and endoscopic therapy, and the incorporation of newer therapies, are needed for stricturing Crohn's disease.

Early Transmural Response Assessed Using Magnetic Resonance Imaging Could Predict Sustained Clinical Remission and Prevent Bowel Damage in Patients with Crohn's Disease Treated with Anti-Tumour Necrosis Factor Therapy

BACKGROUND

Magnetic resonance imaging [MRI] is a promising tool to evaluate therapeutic efficacy in ileocolonic Crohn's disease [CD].

AIMS

We aimed to assess the feasibility of early MRI evaluation (week 12 [W12]) to predict corticosteroid-free remission [CFREM] at W52 and prevent long-term bowel damage.

METHODS

All patients with active CD needing anti-tumour necrosis factor [anti-TNF] therapy were consecutively enrolled in this multicentre prospective study. MRI was performed before starting therapy, at W12 and W52. CFREM was defined as Crohn's Disease Activity Index < 150, C-reactive protein < 5 mg/L and faecal calprotectin < 250 µg/g, with no switch of anti-TNF agents, no bowel resection and no therapeutic intensification between W12 and W52.

RESULTS

Among 46 patients, 22 [47.8%] achieved CFREM at W52. Anti-TNF agents were able to heal almost all CD lesions as soon as W12 [p < 0.05]. Early transmural response defined as a 25% decrease of either Clermont score (odds ratio [OR] = 7.7 [1.7-34.0], p < 0.001) or Magnetic Resonance Index of Activity (OR = 4.2 [1.3-13.3], p = 0.015) was predictive of CFREM at W52. Achieving at least two items on W12-MRI among ulceration healing, disappearance of enlarged lymph nodes or sclerolipomatosis, ΔADC [apparent diffusion coefficient] > +10% or ΔRCE [relative contrast enhancement] > -30% was associated with a likelihood of CFREM at W52 of 84.6% vs 37.5% in patients without transmural response [p < 0.001]. Early transmural response could prevent bowel damage progression over time using Clermont score (hazard ratio = 0.21 [0.0-0.9]; p = 0.037).

CONCLUSION

Evaluation of early transmural response by MRI is feasible and is a promising end point to monitor therapeutic efficacy in patients with CD.

Systematic review: medical therapy for fibrostenosing Crohn's disease

BACKGROUND

Medical therapy and/or endoscopic balloon dilation with intralesional therapies are options for the treatment of small bowel fibrostenotic Crohn's disease (CD).

AIM

To perform a systematic review summarising evidence for efficacy of systemic and endoscopic intralesional medical therapy in established small bowel strictures in adult CD patients.

METHODS

A systematic search of MEDLINE, EMBASE, CENTRAL and Scopus was conducted. Primary outcomes were rates of surgical resection and repeat endoscopic dilation. Pooled event rates from random effects models across studies with 95% confidence intervals were reported.

RESULTS

Ten studies describing systemic medical therapy and eight studies of intralesional injection were included. One randomised controlled trial each for systemic therapy and intrastricture injection were identified. Only observational studies were found for systemic biologic therapies, which exclusively included tumour necrosis factor (TNF) antagonists, while intralesional therapies all involved corticosteroids except for one study that evaluated infliximab. Pooled event rates for surgical resection after systemic and intralesional therapy were 28.3% (95% CI: 18.2%-41.3%) and 18.5% (95% CI: 8.3%-36.2%), respectively over a median follow-up of 23 months (range 5.5-105.8), and 21.8 months (range 5-47). Risk of repeat endoscopic balloon dilation in those with intralesional therapy was 58.3% (95% CI: 36.6%-77.3%) over a median follow-up of 21.8 months (range 5-47).

CONCLUSIONS

There are no favoured therapies for patients with stricturing small bowel CD. Data are lacking for ustekinumab and vedolizumab. No endoscopic intralesional medications provided a clear benefit for prevention of repeat EBD or surgery.