DOP079 The impact of integrating pelvic MRI at diagnosis on early detection of perianal Crohn's disease in pediatrics
Authors: Antaya M , Hudson A , Lerner E P , Nasser K , Carroll M W , Isaac D , Wine E , Perry T , Thompson A , Huynh H Q 
Published: January 2025

Abstract

Background
Perianal Crohn’s disease (CD) can be a severe manifestation of pediatric CD.1,2 It is underrecognized, particularly if asymptomatic, with varied reported incidences (10-60%). Earlier detection by pelvic magnetic resonance imaging (pMR) may alter outcomes.3 The aim of this study was to determine if performing pMR on newly diagnosed pediatric CD patients identifies asymptomatic perianal CD and leads to earlier biologic use and less surgery.

Methods
New CD patients were prospectively enrolled into the Edmonton Pediatric Inflammatory Bowel Disease Clinic (EPIC) registry; EPIC has done baseline pMR since 2018. A retrospective review (2018-2023) collected pMR, perianal exam, symptoms, blood work, calprotectin, medication, and surgery (luminal and/or perianal) data. A blinded radiologist read pMRs using St. James and Parks criteria. Statistics included descriptive, Fisher’s exact test, multivariable logistic regression, and survival analysis.

Results
139 patients were included (63% male, median age 13 [IQR 11-16]). Ninety-six patients (69%) had no pMR perianal disease (pMR-), despite 13/96 (14%) having perianal symptoms and 26/96 (27%) with inflamed (n=6) or non-inflamed (n=14) tags or fissures (n=6). Of the 43 (31%) with pMR+ perianal disease, 27/43 (63%) were asymptomatic (ASx) and 17/43 (40%) had a normal exam. pMR+/ASx patients had physical exam findings that included inflamed (n=4) or non-inflamed (n=5) tags, fissures (n=1), and draining fistula (n=1). Compared to pMR-/ASx, pMR+/ASx patients had a relative risk of 1.40 [95% CI 1.18-1.68] and 1.32 [95% CI 1.17-1.52] of starting a biologic at 6 and 12 months, respectively. For those on biologics for initial maintenance therapy, less anti-TNF was used for pMR+/ASx (n=16/21, 76% of patients on biologics) vs. pMR+/Sx (n=14/14, 100% of patients on biologics). pMR+/Sx needed the most and earlier perianal surgery, but pMR+/ASx also had higher rates and faster time to perianal surgery than pMR-/ASx (p=0.02, Figure 1). Perianal side branch fistula was a significant predictor of perianal surgery (OR 107.6, [95% CI 16.9-2178] p&lt;0.0001).

Conclusion
The majority of pediatric patients with perianal CD identified on pMR had no perianal symptoms and a normal exam. Even with perianal disease being subclinical, these patients needed more and earlier perianal surgery compared to those with negative pMR. Furthermore, side branch fistula on imaging was a significant predictor of needing perianal surgery. Baseline imaging was also helpful for demonstrating the absence of deeper perianal disease in a quarter of patients who did have perianal symptoms and tags/fissures.

References
1.Atia O, Asayag N, Focht G, et al. Perianal Crohn’s Disease Is Associated With Poor Disease Outcome: A Nationwide Study From the epiIIRN Cohort. Clin Gastroenterol Hepatol. 2022;20(3):e484-e495. doi:10.1016/j.cgh.2021.04.007
2.de Zoeten EF, Pasternak BA, Mattei P, Kramer RE, Kader HA. Diagnosis and treatment of perianal Crohn disease: NASPGHAN clinical report and consensus statement. J Pediatr Gastroenterol Nutr. 2013;57(3):401-412. doi:10.1097/MPG.0b013e3182a025ee
3.Chidi VN, Schwartz DA. Imaging of perianal fistulizing Crohn's disease. Expert Rev Gastroenterol Hepatol. 2015;9(6):797-806. doi:10.1586/17474124.2015.1031110