Magnetic resonance index of activity (MaRIA) and Clermont score are highly and equally effective MRI indices in detecting mucosal healing in Crohn's disease

Magnetic Resonance Enterography and Intestinal Ultrasound for the Assessment and Monitoring of Crohn's Disease

Magnetic resonance enterography [MRE] and intestinal ultrasound [IUS] have developed rapidly in the past few decades, emerging as the primary non-invasive options for both diagnosing and monitoring Crohn's disease [CD]. In this review, we evaluate the pertinent data relating to the use of MRE and IUS in CD. We summarise the key imaging features of CD activity, highlight their increasing role in both the clinical and the research settings, and discuss how these modalities fit within the diagnostic pathway. We discuss how they can be used to assess disease activity and treatment responsiveness, including the emergence of activity scores for standardised reporting. Additionally, we address areas of controversy such as the use of contrast agents, the role of diffusion-weighted imaging, and point-of-care ultrasound. We also highlight exciting new developments, including the applications of artificial intelligence. Finally, we provide suggestions for future research priorities.

Reporting of Magnetic Resonance Enterography in Inflammatory Bowel Disease: Results of an Italian Survey

Background/Objectives: Inflammatory bowel diseases (IBDs) are chronic disorders that require close monitoring with imaging techniques such as magnetic resonance enterography (MRE). Standardization of radiological reports is crucial for the optimal management of IBD. We surveyed Italian radiologists regarding their experiences with MRE examinations and reporting for IBD. Methods: All members of the Italian Society of Medical and Interventional Radiology (SIRM) were invited to complete an anonymous questionnaire in April 2023. Comparison tests between variables were assessed using the χ2 test or Fisher exact test according to the least frequency group. Significance level was set for p-value < 0.05. Results: A total of 253 radiologists responded to the survey. Around 70% of the respondents declared personal clinical experience with IBD. Great agreement with the items included and described for both disease activity (i.e., intestinal wall thickness, presence of mucosal ulcers, presence of edema, mucous enhancement) and complications was reported. One-third of the respondents regularly used a structured MRE report. Centers with a high number of IBD patients per year (>1000) mostly used 3 T scanners or both 1.5 T and 3 T scanners (p < 0.001). The incorporation of scores of disease activity was associated with university and high-volume hospitals (p < 0.001). Conclusions: This survey highlighted the current routine practice and experience of MRE reports of IBD patients among Italian radiologists. We found deficiencies in the use of radiological scores in MRE reports and attendance at IBD multidisciplinary meetings.

Establishing a machine learning model based on dual-energy CT enterography to evaluate Crohn's disease activity

OBJECTIVES

The simplified endoscopic score of Crohn's disease (SES-CD) is the gold standard for quantitatively evaluating Crohn's disease (CD) activity but is invasive. This study aimed to develop and validate a machine learning (ML) model based on dual-energy CT enterography (DECTE) to noninvasively evaluate CD activity.

METHODS

We evaluated the activity in 202 bowel segments of 46 CD patients according to the SES-CD score and divided the segments randomly into training set and testing set at a ratio of 7:3. Least absolute shrinkage and selection operator (LASSO) was used for feature selection, and three models based on significant parameters were established based on logistic regression. Model performance was evaluated using receiver operating characteristic (ROC), calibration, and clinical decision curves.

RESULTS

There were 110 active and 92 inactive bowel segments. In univariate analysis, the slope of spectral curve in the venous phases (λHU-V) has the best diagnostic performance, with an area under the ROC curve (AUC) of 0.81 and an optimal threshold of 1.975. In the testing set, the AUC of the three models established by the 7 variables to differentiate CD activity was 0.81-0.87 (DeLong test p value was 0.071-0.766, p > 0.05), and the combined model had the highest AUC of 0.87 (95% confidence interval (CI): 0.779-0.959).

CONCLUSIONS

The ML model based the DECTE can feasibly evaluate CD activity, and DECTE parameters provide a quantitative analysis basis for evaluating specific bowel activities in CD patients.

CRITICAL RELEVANCE STATEMENT

The machine learning model based on dual-energy computed tomography enterography can be used for evaluating Crohn's disease activity noninvasively and quantitatively.

KEY POINTS

Dual-energy CT parameters are related to Crohn's disease activity. Three machine learning models effectively evaluated Crohn's disease activity. Combined models based on conventional and dual-energy CT have the best performance.

AI-luminating Artificial Intelligence in Inflammatory Bowel Diseases: A Narrative Review on the Role of AI in Endoscopy, Histology, and Imaging for IBD

Endoscopy, histology, and cross-sectional imaging serve as fundamental pillars in the detection, monitoring, and prognostication of inflammatory bowel disease (IBD). However, interpretation of these studies often relies on subjective human judgment, which can lead to delays, intra- and interobserver variability, and potential diagnostic discrepancies. With the rising incidence of IBD globally coupled with the exponential digitization of these data, there is a growing demand for innovative approaches to streamline diagnosis and elevate clinical decision-making. In this context, artificial intelligence (AI) technologies emerge as a timely solution to address the evolving challenges in IBD. Early studies using deep learning and radiomics approaches for endoscopy, histology, and imaging in IBD have demonstrated promising results for using AI to detect, diagnose, characterize, phenotype, and prognosticate IBD. Nonetheless, the available literature has inherent limitations and knowledge gaps that need to be addressed before AI can transition into a mainstream clinical tool for IBD. To better understand the potential value of integrating AI in IBD, we review the available literature to summarize our current understanding and identify gaps in knowledge to inform future investigations.

ADC Values for Detecting Bowel Inflammation and Biologic Therapy Response in Patients With Crohn Disease: A Post Hoc Prospective Trial Analysis

BACKGROUND. New biologic agents for Crohn disease (CD) create a need for noninvasive disease markers. DWI may assess bowel inflammation without contrast agents. OBJECTIVE. The purpose of this study was to evaluate ADC values for identifying bowel inflammation and therapeutic response in patients with CD treated with biologic therapy. METHODS. This study entailed post hoc analysis of prospective trial data. Analysis included 89 patients (median age, 37 years; 49 women, 40 men) with CD treated by biologic therapy who underwent MR enterography (MRE) at baseline and 46 weeks after therapy, from March 2013 to April 2021; 43 patients underwent ileocolonoscopy at both time points. Analysis was conducted at the level of small-bowel and colorectal segments (586 segments analyzed). MR index of activity (MaRIA) score and presence of endoscopic ulcers were determined at both time points. One observer measured bowel wall ADC. Diagnostic performance was evaluated. Dichotomous ADC assessments used a threshold of 1301 × 10-6 mm2/s based on initial ROC analysis; dichotomous MaRIA score assessments used a threshold of 11 (moderate to severe inflammation). A second observer repeated ADC measurements in 15 patients. RESULTS. At baseline, ADC had AUC of 0.92, sensitivity of 78.6%, specificity of 91.4%, and accuracy of 88.2% for detecting segments with MaRIA score 11 or greater. At baseline, AUC for detecting endoscopic ulcers was 0.96 for MaRIA score versus 0.87 for ADC (p < .001); sensitivity, specificity, and accuracy were 70.8%, 90.2%, and 85.1% for ADC and 86.2%, 96.2%, and 93.6% for MaRIA score. At follow-up, ADC had AUC of 0.87, sensitivity of 75.4%, specificity of 83.6%, and accuracy of 80.0% for detecting improvement in MaRIA score to less than 11. At follow-up, AUC for detecting endoscopic ulcer healing was 0.94 for MaRIA score versus 0.84 for ADC (p = .01); sensitivity, specificity, and accuracy were 70.7%, 95.8%, and 84.4% for ADC and 90.2%, 100.0%, and 95.6% for MaRIA score. Interobserver agreement for ADC, based on intraclass correlation coefficient, was 0.70 at baseline and 0.65 at follow-up. CONCLUSION. The findings do not support use of ADC rather than MaRIA scores for detecting biologic therapy response. CLINICAL IMPACT. ADC may have an adjunct role in assessing bowel inflammation in CD, but showed limited performance for detecting biologic therapy response.

Wall Thickness Ratio-A New Magnetic Resonance Parameter-Is Associated With the Outcome of Biological Therapy in Patients With Ileal and Ileocolonic Crohn's Disease

GOALS

The present study was aimed at identifying a new magnetic resonance enterography (MRE) parameter assessing the clinical outcome of biological therapy in patients with active ileal/ileocolonic Crohn's disease (CD).

BACKGROUND

Transmural healing (TH) has been associated with improved outcomes in CD. However, some patients with clinical remission and inactive disease at endoscopy do not achieve TH.

MATERIALS AND METHODS

Ileal/ileocolonic CD patients scheduled for biological therapy were prospectively evaluated, at baseline (T0) and after 1 year of treatment (T1), with Harvey Bradshaw Index score, blood tests, ileocolonscopy, and MRE. Clinical activity was assessed after 2 years of treatment (T2). Wall thickness ratio (WTR) was calculated in the same affected ileal segment, as the ratio between the ileum wall thickness value at T1 and the ileum wall thickness value at T0.

RESULTS

A total of 103 patients were included. Mean WTR at T1 in nonresponders was significantly higher than in responders. At receiver operating characteristic analysis, WTR values were significantly associated to biological therapy responsiveness. A WTR cutoff value of 0.77 mm was identified to discriminate responders from nonresponders (sensitivity: 79%; specificity: 67%). In responders, the proportion of patients with a WTR<0.77 was significantly higher than the proportion of patients achieving TH at T1. Among patients achieving endoscopic remission, 11/29 (37.9%) presented TH, while 20/29 (68.9%) presented WTR<0.77 ( P : 0.035). At multivariate logistic regression analysis, WTR<0.77 was significantly associated to biological therapy response.

CONCLUSION

WTR index represents an easy-to-calculate MRE parameter and seems to be a promising tool for monitoring therapeutic response in CD patients during biological therapy.

MR Enterography Scores Correlate with Degree of Mucosal Healing in Pediatric Crohn's Disease: A Pilot Study

Objectives

MR enterography (MRE) Index of Activity (MaRIA) and Clermont are validated scores that correlate with Crohn's disease (CD) activity; however, the Clermont score has not been validated to correlate with the degree of change in mucosal inflammation post induction treatment in children. This pilot study evaluated if MaRIA and Clermont scores can serve as surrogates to ileocolonoscopy for assessing interval change in mucosal inflammation in pediatric CD post-induction treatment.

Methods

Children with known or newly diagnosed ileocolonic CD starting or changing therapy underwent ileocolonoscopy, scored with simple endoscopic score for Crohn's disease (SES-CD), and MRE on the same day at two time points (Week 0 and 12). Accuracy of global MaRIA and Clermont indices relative to ileocolonoscopy in detecting degree of post-treatment interval change in mucosal inflammation was assessed through correlational coefficients (r). Inter-reader agreement was calculated for imaging scores through intraclass correlation (ICC).

Results

Sixteen children (mean age 11.5 ± 2.8) were evaluated. Global MaRIA/Clermont correlated with SES-CD in detecting the degree of change in mucosal inflammation (r = 0.676 and r = 0.677, P < 0.005, respectively). Correlation for pooled timepoint assessments between SES-CD and global MaRIA/Clermont was moderate (r = 0.546, P < 0.001 and r = 0.582, P < 0.001, respectively). Inter-rater reliability for global MaRIA and Clermont was good (ICC = 0.809 and ICC = 0.768, respectively, P < 0.001).

Conclusions

MRE-based global scores correlate with endoscopic indices and may be used to monitor disease changes in children with CD undergoing induction treatment, which can advise the physician if treatment changes should be made.

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.

Inflammatory bowel disease cross-sectional imaging: What's new?

Cross-sectional imaging-ultrasonography, computed tomography enterography, and magnetic resonance enterography-is a routine and indispensable tool for patients with Crohn's disease (CD) that helps to detect or monitor disease characteristics before, during, and after CD treatment. New emerging radiological technologies may have further clinical applications in the management of CD. In this review article, we focus on the latest developments in cross-sectional imaging in CD research, including its role in intra- and extra-luminal lesion detection, intestinal inflammation and fibrosis grading, therapeutic response assessment and outcome prediction, postoperative recurrence detection and prediction, and the gut-brain axis.

Recent advances in clinical practice: advances in cross-sectional imaging in inflammatory bowel disease

Endoscopy remains the reference standard for the diagnosis and assessment of patients with inflammatory bowel disease (IBD), but it has several important limitations. Cross-sectional imaging techniques such as magnetic resonance enterography (MRE) and intestinal ultrasound (IUS) are better tolerated and safer. Moreover, they can examine the entire bowel, even in patients with stenoses and/or severe inflammation. A variety of cross-sectional imaging activity scores strongly correlate with endoscopic measures of mucosal inflammation in the colon and terminal ileum. Unlike endoscopy, cross-sectional techniques allow complete visualisation of the small-bowel and assess for extraintestinal disease, which occurs in nearly half of patients with IBD. Extramural findings may predict outcomes better than endoscopic mucosal assessment, so cross-sectional techniques might help identify more relevant therapeutic targets. Coupled with their high sensitivity, these advantages have made MRE and IUS the primary non-invasive options for diagnosing and monitoring Crohn's disease; they are appropriate first-line investigations, and have become viable alternatives to colonoscopy. This review discusses cross-sectional imaging in IBD in current clinical practice as well as research lines that will define the future role of these techniques.

Inflammatory Bowel Disease Treatments and Predictive Biomarkers of Therapeutic Response

Inflammatory bowel disease (IBD) is a chronic immune-mediated inflammation of the gastrointestinal tract with a highly heterogeneous presentation. It has a relapsing and remitting clinical course that necessitates lifelong monitoring and treatment. Although the availability of a variety of effective therapeutic options including immunomodulators and biologics (such as TNF, CAM inhibitors) has led to a paradigm shift in the treatment outcomes and clinical management of IBD patients, some patients still either fail to respond or lose their responsiveness to therapy over time. Therefore, according to the recent Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE-II) recommendations, continuous disease monitoring from symptomatic relief to endoscopic healing along with short- and long-term therapeutic responses are critical for providing IBD patients with a tailored therapy algorithm. Moreover, considering the high unmet need for novel therapeutic approaches for IBD patients, various new modulators of cytokine signaling events (for example, JAK/TYK inhibitors), inhibitors of cytokines (for example IL-12/IL-23, IL-22, IL-36, and IL-6 inhibitors), anti-adhesion and migration strategies (for example, β7 integrin, sphingosine 1-phosphate receptors, and stem cells), as well as microbial-based therapeutics to decolonize the bed buds (for example, fecal microbiota transplantation and bacterial inhibitors) are currently being evaluated in different phases of controlled clinical trials. This review aims to offer a comprehensive overview of available treatment options and emerging therapeutic approaches for IBD patients. Furthermore, predictive biomarkers for monitoring the therapeutic response to different IBD therapies are also discussed.

Radiology plus ileocolonoscopy versus radiology alone in Crohn's disease: prognosis prediction and mutual agreement

BACKGROUND/AIMS

The optimal tools for monitoring Crohn's disease (CD) are controversial. We compared radiology plus ileocolonoscopy and radiology alone in terms of prognosis prediction and evaluated the agreement between radiologic and ileocolonoscopic findings in patients with CD.

METHODS

Patients with CD who were followed up with computed tomography enterography (CTE) or magnetic resonance enterography (MRE) alone or CTE or MRE plus ileocolonoscopy were retrospectively recruited. Time to relapse was investigated to evaluate the difference in prognosis using the log-rank and Cox regression tests, and the agreement between radiologic and ileocolonoscopic findings was determined using a kappa value.

RESULTS

A total of 501 patients with CD in clinical remission who underwent CTE or MRE and/or ileocolonoscopy were analyzed. Of these, 372 (74.3%) patients underwent CTE or MRE alone and 129 (25.7%) patients underwent CTE or MRE plus ileocolonoscopy. The cumulative maintenance rate of clinical remission between the two groups was not significantly different (p = 0.526, log-rank test). In multivariate analysis, age <40 years (hazard ratio [HR], 2.756; 95% confidence interval [CI], 1.263 to 6.013) and a history of steroid use (HR, 2.212; 95% CI, 1.258 to 3.577) were found to independently predict an increased risk for clinical relapse in patients with CD in clinical remission. Radiologic and ileocolonoscopic findings had a moderate degree of agreement (κ = 0.401, -0.094 to 0.142). The comparison of agreement between radiologic and ileocolonoscopic findings was the highest in the anastomotic site (κ = 0.749, -0.168 to 0.377).

CONCLUSION

Radiology plus ileocolonoscopy was not superior to radiology alone in predicting the prognosis of CD.

Current noninvasive modalities in Crohn's disease monitoring

Crohn’s disease (CD) is characterized by a remitting and relapsing course. Longstanding active CD may result in accumulating intestinal damage and disease-related complications. In contrast, mucosal healing is associated with significant improvement in the health-related quality of life, longer periods of disease remission and lower risk of disease progression, complications, hospitalizations, intestinal surgeries, as well as a lower risk of developing colorectal cancer. Mucosal healing, the new treatment endpoint in CD, made necessary the development of noninvasive, accurate, objective and reliable tools for the evaluation of CD activity. Ileocolonoscopy with biopsies remains the reference standard method for the evaluation of the colonic and terminal ileal mucosa. However, it is an invasive procedure with a low risk of complications, allowing the investigation of only a small part of the small bowel mucosa without being able to assess transmural inflammation. These disadvantages limit its role in the frequent follow up of CD patients. In this review, we present the currently available biomarkers and imaging modalities for the noninvasive assessment of CD activity.

Can the simplified magnetic resonance index of activity be used to evaluate the degree of activity in Crohn's disease?

Background and aims

A simplified magnetic resonance index of activity (MaRIAs) was recently proposed. Our aim was to verify whether MaRIAs can accurately assess the activity degree of CD.

Methods

We retrospectively analyzed the MRI, ileocolonoscopy, fecal calprotectin (FC), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) data of 93 CD patients. With the SES-CD as the gold standard, MaRIAs’ accuracy, the correlation of MaRIAs and SES-CD, FC, ESR, CRP, and interevaluator reliability were assessed.

Results

MaRIAs ≥ 1 detected segments with active CD with 90.80% specificity and 81.37% sensitivity (area under the curve was 0.91, 95% confidence interval 0.87–0.94). MaRIAs score of 2 or more detected severe lesions with 88.89% specificity and 95.12% sensitivity (AUC was 0.96, 95% confidence interval was 0.94–0.98). The MaRIAs score showed a high correlation with the SES-CD in the terminal ileum, transverse colon, right colon, and left colon (r = 0.85, 0.91, 0.88, 0.86, P < 0.001) and a moderate correlation with the SES-CD in the rectum (r = 0.74, P < 0.001). The global MaRIAs score was highly correlated with the global SES-CD (r = 0.90, P < 0.001). The global MaRIAs score was positively correlated with the fecal calprotectin (FC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) (r = 0.77, r = 0.64, and r = 0.68). The intragroup correlation coefficient (ICC) of the two physicians was nice in the terminal ileum, the right colon, the transverse colon, the left colon and was moderately good in the rectum.

Conclusion

MaRIAs can accurately evaluate the disease activity level of CD and are highly correlated with SES-CD and biomarkers. The interrater reliability of the two physicians was moderately good to nice.

Ultrasonographic Evaluation of Intestinal Fibrosis and Inflammation in Crohn's Disease. The State of the Art

The evaluation of the degree of inflammation and fibrosis, intrinsic elements in intestinal wall damage of Crohn’s disease, is essential to individuate the extent of the lesions and the presence of strictures. This information will contribute to the choice of the appropriate therapeutic approach, the prediction of the response to therapy and the course of the disease. The accurate evaluation of the extent and severity of inflammation and/or fibrosis in Crohn’s disease currently requires histopathological analysis of the intestinal wall. However, in clinical practice and research, transmural assessment of the intestinal wall with cross sectional imaging is increasingly used for this purpose. The B-mode ultrasonograhic characteristics of the intestinal wall, the assessment of its vascularization by color Doppler and I.V. contrast agents, and the evaluation of the mechanical and elastic properties by sonoelastography, may provide useful and accurate information on the severity and extent of inflammation and intestinal fibrosis in Crohn’s disease. The purpose of this review is to provide an update on current sonographic methods to discriminate inflammation and fibrosis in Crohn’s disease.

The value of magnetic resonance enterography in diagnostic difficulties associated with Crohn's disease

Purpose

The diagnosis of Crohn’s disease (CD), one of the inflammatory bowel diseases (IBD), along with ulcerative colitis (UC), is often challenging due to the limitations of small intestine visualisation. Magnetic resonance enterography (MRE) enables imaging of intraluminal and extraintestinal complications without ionizing radiation. The objective of this study is to select CD-related MRE features and determine the feasibility of this technique to indicate a group of patients that should be subjected to more invasive diagnostic procedures.

Material and methods

A total of 131 patients (mean age 25) underwent MRE, 60 of whom had been previously diagnosed with CD and 17 with UC. Additionally, 26 patients with suspected IBD and 28 with other or unknown pathologies were included in the study. Radiological reports of MRE examinations, effectuated using a 1.5-T field strength, were retrospectively analysed regarding radiological features of IBD, such as the following: bowel wall thickening, enhancement, comb sign, stricture, enlarged mesenteric nodes, inflammatory infiltration, and abnormal diffusion restriction in diffusion-weighted imaging. The statistical model was based on machine learning of the Kohonen map, together with univariate and multivariate analysis.

Results

The selected neuron (Neuron 3) incorporated 23 cases of CD, 9 of suspected IBD, 2 patients with UC, and 4 with other pathologies. The statistical analysis identified bowel wall thickening, intestinal stricture, and lymphadenopathy as the 3 MRE findings most associated with Neuron 3 (AUC = 0.919, p = 0.031).

Conclusions

Bowel wall thickening, stricture, and enlarged mesenteric lymph nodes in MRE are independent predictive factors for CD diagnosis; thus, patients presenting these features should undergo further examinations. MRE constitutes a powerful imaging modality in cases of suspected IBD.

Crohn disease: magnetic resonance enterocolonography features of endoscopic ulcer stages reclassified with the healing process and the relationships to prognoses

PURPOSE

This study aimed to compare magnetic resonance enterocolonography (MREC) features among the endoscopic ulcer stages reclassified to include healing ulcers and to assess the prognoses in Crohn disease (CD).

METHODS

Altogether, 89 consecutive patients with CD who had undergone MREC and ileocolonoscopy or balloon-assisted enteroscopy were retrospectively studied. Patients were reclassified into 38 patients with no deep ulcer, seven with healing deep ulcer, and 44 with active deep ulcer stage. MREC score derived from a 5-point MR classification and MR index of activity (MaRIA) were evaluated, and patients were followed-up. The primary endpoint was hospitalization.

RESULTS

Healing deep ulcers had higher values in MREC score and MaRIA than no deep ulcers (p < 0.001), and lower values than active deep ulcers (p < 0.001). The 5-year cumulative rates of hospitalization for no deep ulcer, healing deep ulcer, and active deep ulcers were 24.9, 0, and 52.4% (p < 0.05), respectively. MREC score or MaRIA-positive patients had a higher 5-year cumulative rate of hospitalization than the negative patients (p < 0.01 and p < 0.05, respectively).

CONCLUSION

MREC could reflect the healing stages, and the identification was revealed to be important because of the good prognosis. MREC might be useful to predict prognosis of CD.

Pre-treatment magnetic resonance enterography findings predict the response to TNF-alpha inhibitors in Crohn's disease

BACKGROUND

Identifying predictors of therapeutic response is the cornerstone of personalised medicine.

AIM

To identify predictors of long-term healing of severe inflammatory lesions based on magnetic resonance enterography (MRE) findings in patients with Crohn's disease (CD) treated with tumour necrosis factor alpha (TNF-α) inhibitors.

METHODS

This prospective longitudinal single-centre study included patients with clinically active CD requiring treatment with TNF-α inhibitors with at least one intestinal segment with a severe inflammatory lesion detected by MRE (segmental MaRIA ≥11). MRE data were obtained at baseline, and at weeks 14 and 46. The primary endpoint was healing of severe inflammatory lesions (MaRIA <11) in each segment. The secondary endpoint was healing of all severe inflammatory lesions on a per-patient analysis.

RESULTS

We included 58 patients with 86 intestinal segments with severe inflammatory lesions. At week 46, healing of severe lesions was found in 51/86 (59.3%) segments, and complete healing of inflammatory lesions in all segments was found in 28/58 (48.6%) patients. Multivariable analysis found baseline-negative predictors of long-term healing of severe inflammation were ileal (as opposed to colonic) location (OR 0.00, [0.00-0.56] P = 0.002) and presence of creeping fat on MRE (OR 0.00 [0.00-0.57]; P = 0.001). Persistence of segmental MaRIA score >10.6 at week 14 was a negative predictor of healing at week 46 (OR 0.3 [0.04--0.38]; P < 0.001).

CONCLUSION

In patients with CD, the absence of creeping fat detected at baseline MRE and location of severe inflammatory lesions are clinically relevant predictors of long-term healing of severe inflammation under treatment with TNF-α inhibitors.

Volumetric analysis of small bowel motility in an unselected cohort of patients with Crohn's disease

BACKGROUND

Quantified terminal ileal motility during magnetic resonance enterography (MRE) has been suggested to be used as a biomarker of Crohn's disease (CD). The aim of the present study was to evaluate this method in clinical practice.

METHODS

Healthy volunteers and all consecutive patients referred to MRE during a 2-year period were asked to participate and complete the Irritable Bowel Syndrome-Symptom Severity Scale (IBS-SSS) to assess gastrointestinal symptoms. Medical records were scrutinized, and motility indices (MIs) were calculated from MR images.

KEY RESULTS

Twenty-two healthy controls and 134 examinations with CD were included (inclusion rate: 76.3%). Patients with CD had increased mural thickness of the terminal ileum, increased fecal calprotectin, and more symptoms than controls. Patients with active CD had increased mural thickness of ileum and terminal ileum, higher MR activity indices, and signs of inflammation in laboratory analyses, but similar symptoms, compared with inactive disease. After exclusion of sole colon disease (n = 13), MI inversely correlated with mural thickness in terminal ileum, and MI was lower in active disease versus controls in ileum (P = .019) and terminal ileum (P = .005), and versus inactive disease in terminal ileum (P = .044). The area under the curve of MI in terminal ileum was 0.736 for active CD against healthy controls (P = .002) and 0.682 for active against inactive CD (P = .001). MIs were similar in controls and inactive CD.

CONCLUSIONS AND INTERFERENCES

MI reflects inflammatory activity in the intestine. Alterations in MI did not explain symptomatology in inactive CD, without measurable inflammatory parameters in morphology or laboratory analyses.

Clinical-stage Approaches for Imaging Chronic Inflammation and Fibrosis in Crohn's Disease

The number of imaging-based indices developed for inflammatory bowel disease as research tools, objectively measuring ileocolonic and perianal activity and treatment response, has expanded in the past 2 decades. Created primarily to assess Crohn's disease (CD), there is increasing adoption of these indices into the clinical realm to guide patient care. This translation has been facilitated by validation in adult and pediatric populations, prompted by simplification of score calculations needed for practical application outside the research environment. The majority of these indices utilize magnetic resonance imaging (MRI), specifically MR enterography (MRE) and pelvic MRI, and more recently ultrasound. This review explores validated indices by modality, anatomic site and indication, including for documentation of the presence and extent of CD, disease progression, complications, and treatment response, highlighting those in clinical use or with the potential to be. As well, it details index imaging features used to quantify chronic inflammatory activity, severity, and to lesser extent fibrosis, in addition to their reference standards and any modifications. Validation in the pediatric population of indices primarily developed in adult cohorts such as the Magnetic Resonance Index of Activity (MaRIA), the Simplified Magnetic Resonance Index of Activity (MARIAs), and the MRE global score (MEGS), together with newly developed pediatric-specific indices, are discussed. Indices that may be predictive of disease course and investigational techniques with the potential to provide future imaging biomarkers, such as multiparametric MRI, are also briefly considered.

Which MRI Score and Technique Should Be Used for Assessing Crohn's Disease Activity?

Magnetic resonance (MR) enterography is assuming an increasingly important and central role in the management of patients with Crohn’s disease, as it is not only involved in diagnosis and staging of the disease but also allows for patients’ follow-up, evaluating the response to therapy, and predicting disease outcomes. Several MR scores have been developed but unfortunately there is no globally accepted score. The most widely used scores are the Magnetic Resonance Index of Activity (MaRIA) score, the London score, the Nancy score, and the Clermont score; however, there are multiple differences between these tools in terms of the assessed radiological items, fasting, administration of oral or intravenous contrast, and the use of diffusion-weighted images. Here we reviewed the main characteristics of each MR scoring system to clarify which is the most appropriate score for monitoring disease activity in both clinical practice and clinical trials.

Use of Cross-Sectional Imaging for Tight Monitoring of Inflammatory Bowel Diseases

A treat-to-target strategy with close monitoring of intestinal inflammation is recommended in inflammatory bowel disease (IBD). Ileocolonoscopy remains the gold standard for assessing disease activity in IBD but is a relatively invasive procedure and is impossible to repeat in the context of tight monitoring strategies. In addition to biomarkers, cross-sectional imaging increasingly is used in these patients. Computed tomography is limited by the use of radiation, while the use of magnetic resonance enterography (MRE) is limited by its cost and access. There is growing interest in bowel ultrasound that represents a cost-effective, noninvasive, and well-tolerated modality in clinical practice, but it is operator dependent. Compared with ileocolonoscopy and MRE, bowel US has been shown to have the same level of accuracy in assessing and monitoring disease activity for both CD and UC and thus can be considered a point-of-care test. Diffusion-weighted imaging (DWI) is a MR imaging technique that increasingly is used in both IBD and non-IBD conditions and has been shown to be a valuable and accurate tool for assessing and monitoring IBD activity. Compared with conventional MRE, DWI is quicker, less time consuming, may not require intravenous contrast agent, fasting, bowel cleansing, oral preparation, or rectal preparation. This review discusses the role of these cross-sectional imaging techniques for the management of patients with IBD. In the near future, the value of DWI and ultrasound in assessing IBD will require further investigation in the era of transmural healing in CD and complete mucosal healing, including histologic remission, in ulcerative colitis.

Evaluating inflammatory activity in Crohn's disease by cross-sectional imaging techniques

The evaluation of inflammatory bowel activity in patients with Crohn’s disease has traditionally been a challenge, mainly because of the difficulty in gaining endoscopic access to the small bowel. Historically, barium-based contrast studies were the only option for the evaluation of inflammatory activity in Crohn’s disease. They were gradually replaced by cross-sectional imaging techniques, computed tomography enterography (CTE) and magnetic resonance enterography (MRE) now being the modalities of choice for such evaluations. Those two imaging methods have provided important information regarding intestinal wall involvement and extra-intestinal manifestations of Crohn’s disease, not only assessing lesion characteristics and complications but also quantifying inflammatory bowel activity. The objective of this article is to review the main technical aspects of CTE and MRE, together with their indications, contraindications, and limitations, as well as the CTE and MRE imaging characteristics of inflammatory activity in Crohn’s disease.

Diffusion-weighted imaging and apparent diffusion coefficient values for evaluating terminal ileitis in patients with Crohn's disease

Objective:

To determine the accuracy of diffusion-weighted imaging (DWI) in identifying terminal ileitis in patients with Crohn’s disease.

Materials and Methods:

This was a retrospective study of 38 consecutive patients with Crohn’s disease who underwent magnetic resonance enterography with DWI in a 3.0 T scanner. The patients were divided into two groups, on the basis of colonoscopy and biopsy findings: active inflammation; and inactive disease. Apparent diffusion coefficient (ADC) values were determined, as were the magnetic resonance index of activity (MaRIA) and the Clermont score.

Results:

Of the 38 patients evaluated, 18 (47%) had active inflammation. The patients with active inflammation showed greater restricted diffusion, more pronounced mucosal edema, greater wall thickening, a higher MaRIA, and a higher Clermont score than did those with inactive disease. The level of interobserver agreement (intraclass correlation coefficient) was excellent for the MaRIA and the Clermont score, whereas it was substantial for the ADC values. For identifying colonoscopy-proven inflammation, the best ADC cut-off point was 2.1 × 10⁻³ mm²/s, which had a sensitivity of 88.8% and a specificity of 95.0%, whereas DWI presented an overall accuracy of 89.4%, with a sensitivity of 88.9% and a specificity of 90.0%.

Conclusion:

Visual analysis of the DWI sequence has good accuracy in detecting terminal ileitis in patients with Crohn’s disease. In addition, low ADC values have good sensitivity for detecting colonoscopy-proven inflammation.

Crohn's disease activity before and after medical therapy evaluated by MaRIA score and others parameters in MR Enterography

AIM

Aim of this retrospective study is to evaluate the response to therapy in Crohn's disease (CD) patients studied by MR Enterography (MRE) in comparison with Harvey Bradshaw Index (HBI).

METHODS

One hundred and sixty patients with histological proved CD have undergone MRE in the last years. Forty-six patients who repeated MRE after medical therapy within six months were selected for the study. Magnetic Resonance Index of Activity (MaRIA) was evaluated for each patient and used to define the MR judgment. In MRE we also evaluated wall thickening, longitudinal extension of wall thickening, presence of stratified mural hyperenhancement and extraintestinal signs. The clinical response to therapy was judged based on HBI and classified as improved, worsened or stable disease. Clinical judgment was correlated with MRE findings and the agreement was analysed using the Cohen Kappa test.

RESULTS

Among 46 enrolled patients, 18 (39%) improved clinically, 4 (10%) worsened, 24 (51%) remained stable. MR judgment was in agreement with clinical assessment in 33 patients (72%), showing moderate significant concordance (Kappa = 0.49; p < 0.01). No agreement was observed in 13 (28%) patients. Moreover, clinical improvement was significantly correlated to reduction of wall thickening, reduction of longitudinal extension of the disease and reduction of engorged vasa recta (p < 0.05). Worsening conditions were significantly correlated to increased wall thickening (p = 0.05).

CONCLUSIONS

MRE is useful in evaluating the response to therapy in CD patients.

Magnetic resonance enterography features of small bowel Crohn's disease activity: an inter-rater reliability study of small bowel active inflammation in clinical practice setting

OBJECTIVE

The aim of this study is to determine the interrater agreement in a clinical practice environment for the most commonly used magnetic resonance enterography (MRE) features of Crohn's disease (CD).

METHODS

CD patients with MRE's before and after treatment were retrospectively identified using search queries over a 7-year period (May 2017-September 2017). MRE features of CD comprising components of multiple CD scoring indices were scored by radiologists in the same segment of bowel. Agreement for nominal categorical and continuous variables was assessed using a κ and interclass correlation coefficients, respectively.

RESULTS

80 scans comprised the study population. Moderate interrater agreement was seen in both the pre- and post-treatment MRE's for presence of diffusion restriction (к = 0.43, 0.48; pre- and post-treatment), stricturing disease (к = 0.51, 0.52), overall degree of severity (к = 0.49, 0.59). Substantial agreement was seen in pre- and post-treatment scans for length of involvement (interclass correlation coefficient = 0.67, 0.61). The presence of mucosal ulceration had no agreement (к = -0.07, -0.042).

CONCLUSION

Many MRE features of active CD comprising the major CD scoring indices are reproducible when interpreted by non-CD focused abdominal radiologists. However, the presence of mucosal ulcerations had no agreement and may need more investigation before including this feature as a driver in therapeutic decision making.

ADVANCES IN KNOWLEDGE

Demonstrates the unreliability of mucosal ulceration by non-CD focused abdominal radiologists, targeting a potential area for future education. Key Points The majority of MRE findings incorporated in to many CD scoring indices have fair to moderate inter-rater agreement even when read by non-MRE expert radiologists. Substantial agreement was seen in the length of involved bowel, but this feature is only incorporated in to one of the CD scoring indices. Presence of mucosal ulcerations had no interrater agreement in our study-a feature which is heavily weighted by several CD scoring indices. Research should be focused bridging those features which have poor interrater agreement.

Bowel wall healing assessed using magnetic resonance imaging predicts sustained clinical remission and decreased risk of surgery in Crohn's disease

BACKGROUND

Endoscopic mucosal healing is considered as the best therapeutic target in Crohn's disease (CD) as it is associated with better long-term outcomes. We investigated whether bowel wall healing (BWH) assessed using magnetic resonance imaging (MRI) could predict favorable outcomes and could be a potential therapeutic target.

METHODS

We performed a post hoc analysis from two prospective studies (n = 174 patients). All the patients with previous objective signs of bowel inflammation and assessed by MRI for therapeutic efficacy had a standardized and blinded evaluation, and underwent MRI. Complete BWH was defined as no segmental MaRIA > 7 or no segmental Clermont score > 8.4 and BWH as no segmental MaRIA > 11 or no segmental Clermont score > 12.5. Clinical corticosteroid-free remission (CFREM) was defined as no reappearance or worsening of clinical manifestation leading to therapeutic modification, hospitalization or CD-related surgery. Multivariate analyses were performed including all the relevant parameters.

RESULTS

Overall, 63 patients with CD were included (mean follow-up = 4.8 ± 3.1 semesters). In multivariate analysis (n = 303 semesters), complete BWH or BWH was associated with sustained CFREM according to MaRIA [OR = 4.42 (2.29-26.54); p = 0.042 and OR = 3.43 (1.02-27.02); p = 0.047, respectively] or Clermont score [OR = 3.09 (1.01-12.91); p = 0.049 and OR = 3.88 (1.40-13.80); p = 0.036, respectively]. In multivariate analysis (n = 63 patients), complete BWH or BWH was associated with decreased risk of surgery using MaRIA [HR = 0.16 (0.043-0.63); p = 0.008 and HR = 0.24 (0.07-0.77); p = 0.017, respectively] or Clermont score [HR = 0.24 (0.07-0.78); p = 0.016 and HR = 0.23 (0.07-0.76); p = 0.016, respectively].

CONCLUSIONS

MRI endpoints are predictive of favorable outcomes after medical therapy and could be used as therapeutic target in daily practice and clinical trials.

Accuracy of Diffusion-weighted Magnetic Resonance Imaging in Detecting Mucosal Healing and Treatment Response, and in Predicting Surgery, in Crohn's Disease

BACKGROUND AND AIMS

The Nancy score is a luminal Crohn's disease [CD] activity index applied in diffusion-weighted magnetic resonance imaging [DW-MRI]. We assessed the accuracy of the Nancy score in detecting mucosal healing and treatment response, and in predicting surgery.

METHODS

This was a retrospective, single-centre study of all patients with active CD and serial DW-MRI before and after treatment initiation with a biologic drug, between January 2010 and September 2016. The gold standard was endoscopy. The association between the Nancy score and the cumulative probability of intestinal resection during follow-up was tested combining Kaplan-Meier curves and log-rank testing.

RESULTS

A total of 96 patients were included; 20 had concomitantly undergone endoscopy. The Nancy score correlated well with the Crohn's Disease Endoscopic Index of Severity [r = 0.60 for the total score and r = 0.63 for the segmental score]. A total Nancy score <6 and a segmental Nancy score <2 detected mucosal healing with an area under the receiver operating characteristic curve [AUROC] of 0.82 (95% confidence interval [CI] 0.69-0.94, p <0.0001) and 0.80 [95% CI 0.73-0.87, p <0.0001], respectively. The Nancy score was highly sensitive to changes [Guyatt's responsiveness indices: 1.18 for the total score and 0.85 for the segmental score]. Mucosal healing on DW-MRI after treatment initiation was associated with a lower cumulative probability of intestinal surgery (p = 0.0251, median [interquartile range: IQR] follow-up 2.2 [1.6-3.7] years).

CONCLUSIONS

In CD, the Nancy score accurately detects mucosal healing and treatment response, the latter associated with a lower likelihood of intestinal resection.

Assessment of Ileocolonic Inflammation in Crohn's Disease: Which Surrogate Marker Is Better-MaRIA, Clermont, or PET/MR Index? Initial Results of a Feasibility Trial

Our objective was to define an ¹⁸F-FDG PET/MR enterography index as a hybrid surrogate marker for active ileocolonic inflammation in Crohn's disease (CD) and assess its diagnostic performance in comparison to validated MR indices (MR index of activity [MaRIA], Clermont score). Methods: Fifty-two CD patients with recurrent symptoms underwent ileocolonoscopy and ¹⁸F-FDG PET/MR enterography. Three hundred three ileocolonic segments were assessed for inflammation using MaRIA and the Clermont score as well as the newly defined PET/MR index. On the basis of tobit regression, the PET/MR index was defined as (0.87 × wall thickness) + (1.97 × edema) + (0.83 × ulceration) + (0.55 × SUVmax ratio) + 1.14. The endoscopic activity of inflammation was determined by the simplified endoscopic activity score for CD (SES-CD). Receiver-operating-characteristic curves for each surrogate marker were created and tested against each other using the DeLong test, and diagnostic accuracies were compared using the McNemar test. Correlations between surrogate markers and SES-CD were tested with the Spearman rank correlation test. Results: The PET/MR index showed a comparable sensitivity but a significantly higher specificity and accuracy than MaRIA and the Clermont score in predicting both active and severe inflammation (active inflammation: specificities of 0.933, 0.711, and 0.707 and accuracies of 0.921, 0.739, and 0.736, P < 0.001; severe inflammation: specificities of 0.91, 0.81, and 0.785 and accuracies of 0.914, 0.818, and 0.795, P < 0.01, respectively). All surrogate markers correlated moderately with SES-CD on a segmental basis and a global level (0.5 < ρ < 0.7, all P < 0.001). Conclusion: As a hybrid surrogate marker comprising MR parameters and the PET component, the PET/MR index yielded significantly improved specificity and diagnostic accuracy compared with conventional MR indices (MaRIA and the Clermont score), demonstrating its high potential for noninvasive assessment of CD.

New cross-sectional imaging in IBD

PURPOSE OF REVIEW

Cross-sectional imaging, namely ultrasound, CT and MR enterography, complements clinical and endoscopic monitoring of activity and complications in IBD, and emerging new radiological technologies may have clinical applications in the near future. This review offers an update on the potential role of these new imaging methods in the management of IBD.

RECENT FINDINGS

Specific MR techniques [diffusion-weighted imaging (DWI), diffusion kurtosis imaging (DKI) and magnetization transfer] allow accurate detection of inflammation (DWI and maybe DKI) and fibrosis (magnetization transfer) in Crohn's disease, without the need of intravenous gadolinium administration. ultrasonography developments (elastography, contrast-enhanced ultrasonography, small intestine contrast ultrasonography and multispectral optoacoustic tomography) are promising techniques for evaluation of fibrosis (elastography) and inflammation (contrast ultrasonography). Dose-reduction techniques in CT allow similar quality imaging and diagnostic accuracy with lower radiation exposure. Hybrid imaging (PET/MR and PET/CT) hold promise for grading inflammation in Crohn's disease.

SUMMARY

The potential benefits of new cross-sectional imaging techniques in IBD include better inflammation grading, such as identification of mild degree of activity, which may be relevant whenever assessing response to treatment and, of uttermost importance, accurate preoperative detection and grading of fibrosis in stricturing Crohn's disease, facilitating surgical vs. medical therapeutic decisions.

Small bowel imaging in Crohn's disease patients

Crohn’s disease (CD) is a lifelong, chronic inflammatory bowel disorder. The small bowel (SB) is involved to varying extents, and the clinical course may vary from an inflammatory type to a more complicated one with stricture, fistula, and abscess formation. Esophagogastroduodenoscopy and ileocolonoscopy with biopsies are the conventional endoscopic techniques that usually establish the diagnosis. On the other hand, CD may affect SB segments that cannot be reached through these procedures. Video capsule endoscopy and enteroscopy are additional endoscopic techniques that may allow further SB evaluation in such circumstances. Computed tomographic enterography, magnetic resonance enterography, and ultrasonography are radiologic techniques that serve as a crucial adjunct to endoscopic assessment. They enable the assessment of parts of the bowel that may be difficult to reach with conventional endoscopy; this allows for the detection of active inflammation, penetrating or stricturing disease, and the appreciation of extraintestinal complications. Both endoscopic and radiologic modalities play a role in establishing the diagnosis of CD, as well as determining the disease extent, activity and response to therapy. This review is intended to evaluate these modalities in terms of specificity, sensitivity, potential side-effects, and limiting factors. This should serve as a guide to the clinician for establishing the most appropriate and reliable test within a particular clinical context.

A review of magnetic resonance enterography-based indices for quantification of Crohn's disease inflammation

Magnetic resonance enterography (MRE) is a leading radiological modality in Crohn's disease (CD) and is used together with laboratory findings and endoscopic examinations for the evaluation of patients during initial diagnosis and follow up. Over the years, there has been great progress in the understanding of CD and there is a continuous strive to achieve better monitoring of patients and to develop new modalities which will predict disease course and thus help in clinical decisions making. An objective evaluation of CD using a quantification score is not a new concept and there are different clinical, endoscopies, radiological and combined indices which are used in clinical practice. Such scores are a necessity in clinical trials on CD for evaluation of disease response, however, there is no consensus of the preferred MRE score and they are not routinely used. This review presents MRE-based indices in use in the last decade: the Magnetic Resonance Index of Activity (MaRIA), the Clermont score, the Crohn's Disease Magnetic Resonance Imaging (MRI) Index (CDMI), the Magnetic Resonance Enterography Global Score (MEGS) and the Lemann index. We compare the different indices and evaluate the clinical research that utilized them. The aim of this review is to provide a reference guide for researchers and clinicians who incorporate MRE indices in their work. When devising future indices, accumulated data of the existing indices must be taken into account, as each of the current indices has its own strengths and weakness.

Faecal calprotectin and magnetic resonance imaging in detecting Crohn’s disease endoscopic postoperative recurrence

AIM

To assess magnetic resonance imaging (MRI) and faecal calprotectin to detect endoscopic postoperative recurrence in patients with Crohn’s disease (CD).

METHODS

From two tertiary centers, all patients with CD who underwent ileocolonic resection were consecutively and prospectively included. All the patients underwent MRI and endoscopy within the first year after surgery or after the restoration of intestinal continuity [median = 6 mo (5.0-9.3)]. The stools were collected the day before the colonoscopy to evaluate faecal calprotectin level. Endoscopic postoperative recurrence (POR) was defined as Rutgeerts’ index ≥ i2b. The MRI was analyzed independently by two radiologists blinded from clinical data.

RESULTS

Apparent diffusion coefficient (ADC) was lower in patients with endoscopic POR compared to those with no recurrence (2.03 ± 0.32 vs 2.27 ± 0.38 × 10^-3 mm²/s, P = 0.032). Clermont score (10.4 ± 5.8 vs 7.4 ± 4.5, P = 0.038) and relative contrast enhancement (RCE) (129.4% ± 62.8% vs 76.4% ± 32.6%, P = 0.007) were significantly associated with endoscopic POR contrary to the magnetic resonance index of activity (MaRIA) (7.3 ± 4.5 vs 4.8 ± 3.7; P = 0.15) and MR scoring system (P = 0.056). ADC < 2.35 × 10^-3 mm²/s [sensitivity = 0.85, specificity = 0.65, positive predictive value (PPV) = 0.85, negative predictive value (NPV) = 0.65] and RCE > 100% (sensitivity = 0.75, specificity = 0.81, PPV = 0.75, NPV = 0.81) were the best cut-off values to identify endoscopic POR. Clermont score > 6.4 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74), MaRIA > 3.76 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74) and a MR scoring system ≥ MR1 (sensitivity = 0.54, specificity = 0.82, PPV = 0.70, and NPV = 0.70) demonstrated interesting performances to detect endoscopic POR. Faecal calprotectin values were significantly higher in patients with endoscopic POR (114 ± 54.5 μg/g vs 354.8 ± 432.5 μg/g; P = 0.0075). Faecal calprotectin > 100 μg/g demonstrated high performances to detect endoscopic POR (sensitivity = 0.67, specificity = 0.93, PPV = 0.89 and NPV = 0.77).

CONCLUSION

Faecal calprotectin and MRI are two reliable tools to detect endoscopic POR in patients with CD.