Atypical course of fistulas and intramural abscesses in patients with perianal fistula on magnetic resonance imaging: predictive signs for Crohn's disease?

KURU ÖZ D., Yılmazer Zorlu S., Ergüden R., ERDEN G. A., AKYOL C.

Clinical Radiology, cilt.92, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 92
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.crad.2025.107198
  • Dergi Adı: Clinical Radiology
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, CINAHL, EMBASE
  • Ankara Üniversitesi Adresli: Evet

Özet

AIM The aim of this study is to investigate the relationship between Crohn’s disease (CD) and atypical fistula characteristics, including their course within the external anal sphincter (EAS) and concurrent intramural abscesses, and to assess their role in distinguishing CD-associated fistulas. MATERIALS AND METHODS A retrospective analysis of 624 patients with perianal fistulas was conducted via magnetic resonance imaging (MRI). Fistulas were classified by type, complexity, activity, course within the EAS, and presence of intramural abscesses. Logistic regression analyses identified factors differentiating CD-associated fistulas from idiopathic fistulas. RESULTS Among the 624 patients, 109 had CD. Fistulas coursing within the EAS were observed in 10 % of patients, primarily of cryptoglandular origin (87.3 %), with a minority associated with CD (7.9 %). Intramural abscesses, which are significantly more prevalent in CD patients ( P <.001), increased the likelihood of CD by 9.4-fold (95 % CI: 3.08-28.70, P <.001). Additionally, complex fistulas (OR = 2.46, P <.001) and internal orifice localisation in the proximal anal canal or distal rectum (OR = 2.26, P =.002) were identified as independent predictors of CD. CONCLUSION Intramural abscesses, complex fistulas, and specific internal orifice locations are strong indicators of CD in patients with perianal fistulas. Furthermore, the course of fistulas within the EAS, although not strongly associated with CD, is a critical feature for treatment planning. Multidisciplinary studies are essential to refine classification systems and assess the prognostic implications of EAS-involving fistulas.