Abstract Background Radiological healing of fistulae on MRI is the ultimate therapeutic goal in Class 2a perianal fistulising Crohn’s disease (pfCD), yet its definition is often vague and inconsistent. The TOpClass consortium recently established an international consensus definition of a radiologically healed fistula (TOpClass-Radiologically Healed) in pfCD (Figure 1)(1). This study aimed to validate that definition in real-world clinical practice. Methods VALIDATE-PERIANAL was a retrospective, multi-centre study conducted across three international expert centres. Patients with pfCD with a baseline MRI scan showing active disease and follow-up MRI evidence of radiological fistula healing between 2021–2023 were identified. Paired scans were independently reviewed by three gastrointestinal radiologists using TOpClass-Radiologically Healed criteria, with consensus adjudication. A minimum of 12-months clinical follow-up was required. The primary outcome was sustained clinical remission; secondary outcomes included inter-rater reliability, which was assessed via Cohen’s kappa, and rates of proctectomy and stoma formation. Results Of 977 patients screened, 40 patients with pfCD met the inclusion criteria. Only 14/40 (35%) fulfilled TOpClass-Radiologically Healed criteria. Sustained clinical remission was achieved in 93% of patients who met the stringent TOpClass-Radiologically Healed criteria. Clinical recurrence occurred in 1/14 (7%) of TOpClass-Radiologically Healed patients versus 8/26 (30.8%) in the non-Radiologically Healed group (RR 4.3 0.60–31.0, p = 0.12), with a median follow-up of 28 months. Inter-rater agreement was excellent (κ 0.89–0.95) (Table 1). There was a trend toward lower rates of proctectomy and stoma formation in Radiologically Healed compared to non-Radiologically Healed patients. Conclusion The TOpClass-Radiologically Healed definition predicted sustained clinical remission in 93% of cases and demonstrated excellent inter-rater reliability. It was easy to use, practical and not reliant on contrast. These results support TOpClass-RH as a robust, clinically meaningful radiological endpoint, providing a reliable benchmark for international trials and diagnostic stratification in pfCD. References: 1. Anand E, Devi J, Ballard DH, Joshi S, Tozer P, Hart A, et al. Defining radiological healing in perianal fistulising Crohn’s Disease: a TOpClass global expert Delphi consensus. Clinical Gastroenterology and Hepatology: The Official Clinical Practice Journal of the American Gastroenterological Association. 2025; S1542-3565(25)00248-4. https://doi.org/10.1016/j.cgh.2025.02.009. Conflict of interest: Mr. Anand, Easan: No conflict of interest van Croonenburg, Thirza: No conflict of interest Samaan, Sami: No conflict of interest Tozer, Philip: No conflict of interest Hart, Ailsa: No conflict of interest Deepak, Parakkal: Grant: Johnson and Johnson, Pfizer, AbbVie, Arena Pharmaceuticals, Bristol Myers Squibb, Takeda Pharmaceuticals, Prometheus Biosciences, Teva Pharmaceuticals, Merck, ExeGI Pharmaceuticals, AGMB, Landos Pharmaceuticals, Tr1X, and Boehringer Ingelheim. Personal Fees: AbbVie, Bristol Myers Squibb, CorEvitas LLC, Sandoz, Takeda Pharmaceuticals, Merck, Celltrion, Eli Lilly Ballard, David: David H. Ballard, MD. Consulting Direct Biologics, Merck. Stoker, Jaap: No conflict of interest Lung, Phillip FC: No conflict of interest Figure 1. TOpClass-Radiologically Healed definition Table 1. Inter-rater reliability and agreement of TOpClass-Radiologically Healed definition
Anand et al. (Thu,) studied this question.