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.

Avoiding contrast-enhanced sequences does not compromise the precision of the simplified MaRIA for the assessment of non-penetrating Crohn's disease activity.

OBJECTIVES: Patients with Crohn's disease (CD) require multiple assessments with magnetic resonance enterography (MRE) from a young age. Standard MRE protocols for CD include contrast-enhanced sequences. Gadolinium deposits in brain tissue suggest avoiding gadolinium could benefit patients with CD. This study aimed to compare the accuracy of the simplified Magnetic Resonance Index of Activity (sMaRIA) calculated with and without contrast-enhanced sequences in determining the response to biologic drugs in patients with CD. METHODS: This post hoc analysis of a prospective study included patients with CD with endoscopic ulceration in ≥ 1 intestinal segment starting biologic drug therapy. Two blinded radiologists used the sMaRIA to score images obtained at baseline and week 46 of treatment first using only unenhanced sequences (T2-sMaRIA) and 1 month later using both unenhanced and enhanced images (CE-sMaRIA). We calculated the rates of agreement between T2-sMaRIA, CE-sMaRIA, and ileocolonoscopy for different conceptualizations of therapeutic response. RESULTS: A total of 46 patients (median age, 36 years [IQR: 28-47]) were included. Agreement with ileocolonoscopy was similar for CE-sMaRIA and T2-sMaRIA in identifying ulcer healing (kappa = 0.74 [0.55-0.93] and 0.70 [0.5-0.9], respectively), treatment response (kappa = 0.53 [0.28-0.79] and 0.44 [0.17 - 0.71]), and remission (kappa = 0.48 [0.22-0.73] and 0.43 [0.17-0.69]). The standardized effect size was moderate for both CE-sMaRIA = 0.63 [0.41-0.85] p < 0.001 and T2-sMaRIA = 0.58 [0.36-0.80] p < 0.001. CONCLUSIONS: sMaRIA with and without contrast-enhanced images accurately classified the response according to different therapeutic endpoints determined by ileocolonoscopy. KEY POINTS: • The simplified Magnetic Resonance Index of Activity is accurate for the assessment of Crohn's disease activity, severity, and therapeutic response, using four dichotomic components that can be evaluated without the need of using contrast-enhanced sequences, representing a practical and safety advantage, but concerns have been expressed as to whether the lack of contrast sequences may compromise precision. • The simplified Magnetic Resonance Index of Activity can assess the response to biologic therapy in patients with Crohn's disease without the need for intravenous contrast agents obtaining comparable results without and with contrast-enhanced sequences. • Avoiding intravenous contrast agents could reduce the duration of the MRE examination and its cost and would increase the acceptance and safety of MRE in clinical research in patients with Crohn's disease.

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.

Differentiation of fibrotic and inflammatory component of Crohn's disease-associated strictures.

Patients with Crohn's disease (CD) commonly develop bowel strictures, which may contain various degrees of inflammation and fibrosis. While predominantly inflammatory strictures may benefit from a medical anti-inflammatory treatment approach, fibrotic strictures would require endoscopic balloon dilation or surgery. Cross-sectional imaging surpasses endoscopy for characterization of stenotic segments and potentially may contribute to the optimal clinical management of these patients. This short review aims to discuss the potentialities and limitations of cross-sectional imaging techniques for assessing bowel fibrosis in patients with CD.

Validation of the Simplified Magnetic Resonance Index of Activity [sMARIA] Without Gadolinium-enhanced Sequences for Crohn's Disease.

BACKGROUND: Gadolinium-enhanced sequences are not included in the simplified Magnetic Resonance Index of Activity [sMARIA], but in the derivation of this index readers had access to these sequences. The current study aimed to validate the sMARIA without gadolinium-enhanced sequences for assessing disease activity, severity, and response to treatment in patients with Crohn's disease. METHODS: We prospectively included patients with active Crohn's disease and at least one segment with severe inflammation [ulcers] at ileocolonoscopy, who required treatment with biologic drugs. Patients were evaluated by both magnetic resonance enterography [MRE] and ileocolonoscopy at baseline and 46 weeks after initiation of medical treatment. We compared the quantification of disease activity and response to treatment with sMARIA versus with ileocolonoscopy Crohn's Disease Index of Severity [CDEIS], considered the gold standard. RESULTS: Data from both MRE and ileocolonoscopy 46 weeks after treatment initiation were available for 39 of the 50 patients. As in the derivation study, the optimal cutoffs were sMARIA ≥1 for predicting active disease (area under the curve [AUC] 0.92) and sMARIA ≥2 for predicting the presence of ulcers at ileocolonoscopy [AUC 0.93]. In evaluating the response to treatment, the sMARIA detected endoscopic ulcer healing at the segment level [sMARIA <2] with 89.5% sensitivity and 87.5% specificity. The sMARIA decreased significantly [p <0.001] in segments achieving endoscopic ulcer healing, but did not change [p = 0.222] in segments with persistent ulceration. CONCLUSIONS: The sMARIA is accurate and reliable in quantifying disease activity and response to treatment in luminal Crohn's disease, without the need for gadolinium-enhanced sequences.

Magnetic Resonance in Crohn Disease: Imaging Biomarkers in Assessing Response to Therapy.

The management of Crohn disease (CD) has entered a new era in which it is imperative to incorporate objective data and symptoms to plan the best therapeutic approach for each patient. Magnetic resonance (MR) imaging provides powerful objective insights into the disease process, and its high sensitivity and specificity for detecting inflammation make it essential for diagnosis and management. Growing evidence indicates that MR provides reliable and accurate information that enables detection of changes after treatment with biological drugs. This article provides an overview of currently established and emerging MR biomarkers for assessing response to treatment in patients with CD.