Assessing quality of magnetic resonance enterography and its impact on disease assessment of ileal Crohn's disease.

BACKGROUND/AIMS: Assessment of quality of magnetic resonance enterography (MRE) in small bowel Crohn's disease (CD) activity evaluation has received little attention. We assessed the impact of bowel distention and motion artifact on MRE activity indices in ileal CD. METHODS: A cohort of patients who underwent contemporaneous MRE and colonoscopy for ileal CD assessment between 2014 and 2021 at 2 centers were audited. An abdominal radiologist blinded to clinical data reviewed each MRE, graded bowel distention and motion artifact upon a pre-specified 3-point scale and calculated the original magnetic resonance index of activity (MaRIA) and simplified MaRIA (sMaRIA), London index and CD MRE index (CDMI). Ileal endoscopic activity was graded via the Simplified Endoscopy Score for CD (SES-CD). The performance of MRE indices in discriminating active disease (SES-CD ≥3) stratified by MRE quality was measured by receiver operator characteristic analyses. RESULTS: One hundred and thirty-seven patients had MRE and colonoscopy within a median of 16 days (range, 0-30 days) with 63 (46%) exhibiting active disease (SES-CD ≥3). Forty-four MREs (32%) were deemed low quality due to motion artifact and/or moderate to poor distention. Low-quality MREs demonstrated reduced discriminative performance between ileal SES-CD ≥3 and MRE indices (MaRIA 0.838 vs. 0.634, sMaRIA 0.834 vs. 0.527, CDMI 0.850 vs. 0.595, London 0.748 vs. 0.511, P<0.05 for all). Individually the presence of any motion artifact markedly impacted the discriminative performance (e.g., sMaRIA area under the curve 0.544 vs. 0.814, P<0.05). CONCLUSIONS: Image quality parameters can significantly impact MRE disease activity interpretation. Quality metrics should be reported, enabling cautious interpretation in lower-quality studies.

Development of a Simple, Serum Biomarker-based Model Predictive of the Need for Early Biologic Therapy in Crohn's Disease.

BACKGROUND: Early or first-line treatment with biologics, as opposed to conventional immunomodulators, is not always necessary to achieve remission in Crohn's disease [CD] and may not be cost-effective. This study aimed to develop a simple model to predict the need for early biologic therapy, in order to risk-stratify CD patients and guide initial treatment selection. METHODS: A model-building study using supervised statistical learning methods was conducted using a retrospective cohort across two tertiary centres. All biologic-naïve CD patients who commenced an immunomodulator between January 1, 2004 and December 31, 2016, were included. A predictive score was derived using Cox regression modelling of immunomodulator failure, and was internally validated using bootstrap resampling. RESULTS: Of 410 patients [median age 37 years, 47% male, median disease duration 4.7 years], 229 [56%] experienced immunomodulator failure [39 required surgery, 24 experienced a new stricture, 44 experienced a new fistula/abscess, 122 required biologic escalation] with a median time to failure of 16 months. Independent predictors of treatment failure included raised C-reactive protein [CRP], low albumin, complex disease behaviour, younger age, and baseline steroids. Highest CRP and lowest albumin measured within the 3 months preceding immunomodulator initiation outperformed baseline measurements. After model selection, only highest CRP and lowest albumin remained and the resultant Crohn's Immunomodulator CRP-Albumin [CICA] index demonstrated robust optimism-corrected discriminative performance at 12, 24, and 36 months (area under the curve [AUC] 0.84, 0.83, 0.81, respectively). CONCLUSIONS: The derived CICA index based on simple, widely available markers is feasible, internally valid, and has a high utility in predicting immunomodulator failure. This requires external, prospective validation.