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

Local Assessment and Small Bowel Crohn's Disease Severity Scoring using AI

RATIONALE AND OBJECTIVES

We present a machine learning and computer vision approach for a localized, automated, and standardized scoring of Crohn's disease (CD) severity in the small bowel, overcoming the current limitations of manual measurements CT enterography (CTE) imaging and qualitative assessments, while also considering the complex anatomy and distribution of the disease.

MATERIALS AND METHODS

Two radiologists introduced a severity score and evaluated disease severity at 7.5 mm intervals along the curved planar reconstruction of the distal and terminal ileum using 236 CTE scans. A hybrid model, combining deep-learning, 3-D CNN, and Random Forest model, was developed to classify disease severity at each mini-segment. Precision, sensitivity, weighted Cohen's score, and accuracy were evaluated on a 20% hold-out test set.

RESULTS

The hybrid model achieved precision and sensitivity ranging from 42.4% to 84.1% for various severity categories (normal, mild, moderate, and severe) on the test set. The model's Cohen's score (κ = 0.83) and accuracy (70.7%) were comparable to the inter-observer agreement between experienced radiologists (κ = 0.87, accuracy = 76.3%). The model accurately predicted disease length, correlated with radiologist-reported disease length (r = 0.83), and accurately identified the portion of total ileum containing moderate-to-severe disease with an accuracy of 91.51%.

CONCLUSION

The proposed automated hybrid model offers a standardized, reproducible, and quantitative local assessment of small bowel CD severity and demonstrates its value in CD severity assessment.

Assessment of intestinal luminal stenosis and prediction of endoscopy passage in Crohn's disease patients using MRI

BACKGROUND

Crohn's disease (CD) is an inflammatory disease of the gastrointestinal tract. The disease behavior changes over time, and endoscopy is crucial in evaluating and monitoring the course of CD. To reduce the economic burden of patients and alleviate the discomfort associated with ineffective examination, it is necessary to fully understand the location, extent, and severity of intestinal stenosis in patients with CD before endoscopy. This study aimed to utilize imaging features of magnetic resonance enterography (MRE) to evaluate intestinal stenosis in patients with CD and to predict whether endoscopy could be passed.

METHODS

MRE data of patients with CD were collected, while age, gender, disease duration, and laboratory test parameters were also gathered. Two radiologists analyzed the images and assessed whether endoscopy could be passed based on the imaging performance. Imaging features of MRE were analyzed in groups based on endoscopy results.

RESULTS

The readers evaluated the imaging performance for 86 patients to determine if endoscopy could be passed and performed a consistency test (compared between two readers k = 0.812, p = 0.000). In the univariate analysis, statistical differences were observed in the degree of T1WI enhancement, thickness of the intestine wall at the stenosis, and diameter of the upstream intestine between the two groups of whether endoscopy was passed. In multivariate logistic regression, the diameter of the upstream intestine was identified to be an independent factor in predicting whether endoscopy was passed or not (OR = 3.260, p = 0.046).

CONCLUSIONS

The utilization of MRE signs for assessing the passage of an endoscope through the narrow segment revealed that the diameter of the upstream intestine emerged as an independent predictor of endoscopic passage. Before performing an endoscopy, MRE can aid in evaluating the passage of the endoscope.

CRITICAL RELEVANCE STATEMENT

This retrospective study explored the imaging features of MRE to evaluate intestinal stenosis in patients with Crohn's disease and determined that the diameter of the upstream intestine of the stenotic segment was an independent predictor in assessing endoscopic passage.

KEY POINTS

• Endoscopy is crucial in evaluating and monitoring the course of Crohn's disease. • The diameter of the upstream intestine of the stenotic segment was an independent predictor in assessing endoscopic passage. • MRE can aid in evaluating the passage of the endoscope in stenotic segments of Crohn's disease.

Defining Magnetic Resonance Imaging Treatment Response and Remission in Crohn's Disease: A Systematic Review

BACKGROUND

Magnetic resonance imaging is increasingly used to assess treatment response in Crohn's disease clinical trials. We aimed to describe the definition of MRI response and remission as assessed by magnetic resonance enterography [MRE] to evaluate treatment efficacy in these patients.

METHODS

Electronic databases were searched up to May 1, 2023. All published studies enrolling patients with inflammatory bowel disease and assessment of treatment efficacy with MRE were eligible for inclusion.

RESULTS

Eighteen studies were included. All studies were performed in patients with Crohn's disease. The study period ranged from 2008 to 2023. The majority of studies used endoscopy as the reference standard [61.1%]. MRE response was defined in 11 studies [61.1%]. Five scores and nine different definitions were proposed for MRE response. MRE remission was defined in 12 studies [66.7%]. Three scores and nine different definitions for MRE remission were described. The MaRIA score was the most frequent index used to evaluate MRE response [63.6%] and remission [41.7%]. MRE response was defined as MaRIA score <11 in 63.6% of studies using this index. In 60% of studies using the MaRIA score, MRE remission was defined as MaRIA score <7. In addition, 11 different time points of assessment were reported, ranging from 6 weeks to years.

CONCLUSION

In this systematic review, significant heterogeneity in the definition of MRE response and remission evaluated in patients with Crohn's disease was observed. Harmonization of eligibility and outcome criteria for MRE in Crohn's Disease clinical trials is needed.

Crohn's Disease: Basic Characteristics of the Disease, Diagnostic Methods, the Role of Biomarkers, and Analysis of Metalloproteinases: A Review

Crohn's disease is a chronic inflammatory bowel disease that affects the ileum and/or large intestine. At the same time, it can also affect any other part of the human body, i.e., from the mouth to the anus. In Crohn's disease, the physiology and functioning of the epithelial barrier are inhibited due to the correlation of various factors, such as the environment, genetic susceptibility or intestinal microbiota. The symptoms are very troublesome and cause a significant reduction in quality of life, sometimes occurring with paralyzing permanent damage to the digestive tract, requiring enteral or parenteral nutrition throughout life. In order to make a proper and accurate diagnosis, an appropriately selected diagnostic path in a given clinical entity is necessary. Standard diagnostic methods are: laboratory examination, histopathological examination, endoscopic examination, X-ray, computed tomography, ultrasound examination and magnetic resonance imaging. Medical biology and the analysis of metalloproteinases have also proved helpful in diagnosing changes occurring as a result of Crohn's disease. Here we provide a thorough review of the latest reports on Crohn's disease and its genetic conditions, symptoms, morphology, diagnosis (including the analysis of Crohn's disease biomarkers, i.e., metalloproteinases) and treatment.

Magnetic Resonance Imaging of the Gastrointestinal Tract: Current Role, Recent Advancements and Future Prospectives

This review focuses on the role of magnetic resonance imaging (MRI) in the evaluation of the gastrointestinal tract (GI MRI), analyzing the major technical advances achieved in this field, such as diffusion-weighted imaging, molecular imaging, motility studies, and artificial intelligence. Today, MRI performed with the more advanced imaging techniques allows accurate assessment of many bowel diseases, particularly inflammatory bowel disease and rectal cancer; in most of these diseases, MRI is invaluable for diagnosis, staging, and disease monitoring under treatment. Several MRI parameters are currently considered activity biomarkers for inflammation and neoplastic disease. Furthermore, in younger patients with acute or chronic GI disease, MRI can be safely used for short-term follow-up studies in many critical clinical situations because it is radiation-free. MRI assessment of functional gastro-esophageal and small bowel disorders is still in its infancy but very promising, while it is well established and widely used for dynamic assessment of anorectal and pelvic floor dysfunction; MRI motility biomarkers have also been described. There are still some limitations to GI MRI related to high cost and limited accessibility. However, technical advances are expected, such as faster sequences, more specific intestinal contrast agents, AI analysis of MRI data, and possibly increased accessibility to GI MRI studies. Clinical interest in the evaluation of bowel disease using MRI is already very high, but is expected to increase significantly in the coming years.

Comparison of the magnetic resonance scoring systems for Crohn's disease activity: MaRIA, simplified MaRIA, and Nancy scores

PURPOSE

The most widely used score for assessing the activity of Crohn's disease (CD) is the Magnetic Resonance Index of Activity (MaRIA) score, but it is time-consuming. The aim of this study was to compare the diagnostic accuracy of MaRIA score to the other two easily calculated scores.

METHODS

Between January 2011 and May 2021, 67 patients with CD who underwent MRE and ileocolonoscopy within 2 weeks were enrolled. The MRE-based scores including the MaRIA score, simplified MaRIA (sMaRIA) score, and Nancy score for each colonic segment and terminal ileum were calculated and correlated with the ileocolonoscopic findings. The simplified endoscopic score for Crohn's disease (SES-CD) was considered the gold standard.

RESULTS

A total of 343 intestinal segments were included in the analysis, of which 109 (31.8%) showed active inflammation on ileocolonoscopy. The areas under the receiver operating characteristic curve (AUC) of the MaRIA, sMaRIA, and Nancy scores for detecting active disease were 0.752, 0.764, and 0.765, respectively. In the sub-analysis for different indications, the MaRIA and sMaRIA scores showed a higher AUC (0.721 and 0.741) than the Nancy score (0.652) for disease monitoring.

CONCLUSION

The sMARIA and Nancy scores showed comparable diagnostic accuracy to the MaRIA score, and thus could be used as alternatives to the MaRIA score. Furthermore, considering the range of application, especially for disease monitoring, the sMaRIA score may be more suitable for use in clinical practice.

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.

MR-enterography: role in the assessment of suspected anastomotic recurrence of Crohn disease after ileocolic resection

PURPOSE

To determine the potential of magnetic resonance-enterography (MRE) in the assessment of the anastomotic status in patients with Crohn disease and prior ileocolic resection.

METHODS

A total of 62 MRE examinations obtained in 52 patients with Crohn disease who had previously undergone ileocolic resection were retrospectively reviewed by two readers in consensus. MRE features (anastomotic wall thickening, wall stratification, wall enhancement pattern and degree, DWI signal intensity, ADC values, lymph nodes, comb sign and complications) were compared to clinical, endoscopic and histological findings that served as standard of reference. Sensitivity, specificity and accuracy of MRE were calculated.

RESULTS

At univariate analysis, anastomotic wall thickening, anastomotic wall stratification, segmental wall enhancement, moderate wall enhancement, early and mucosal enhancement, and moderate/marked hyperintensity on diffusion-weighed imaging (DWI) were the most discriminative MRE features for differentiating between normal and abnormal anastomoses (p < 0.001 for all variables). Anastomotic wall thickening and segmental anastomotic wall enhancement were the two most sensitive and accurate MRE variables for the diagnosis of abnormal anastomosis with sensitivities of 82% (95% CI: 67-92%) and accuracies of 84% (95% CI: 72-92%). At univariate analysis, hyperintensity on DWI of the anastomotic site was the most sensitive finding for distinguishing between inflammatory recurrence and fibrostenosis (sensitivity, 89%; 95% CI: 67-99%).

CONCLUSIONS

MRE provides objective and relatively specific morphological criteria that help detect abnormal ileocolic anastomosis, but performances are lower when differentiating between inflammatory recurrence and fibrostenosis. DWI may be useful in identifying pathologic anastomosis and, in particular, in distinguishing between inflammatory recurrence and fibrostenosis.

Imaging Inflammation - From Whole Body Imaging to Cellular Resolution

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view.