VALIDATE-PERIANAL: an international real-world multi-centre exploratory validation of the TOpClass definition of a radiologically healed fistula in perianal fistulising Crohn’s disease
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Objectives:
Radiological healing on MRI is the ultimate therapeutic goal in Class 2a perianal fistulising Crohn’s disease (pfCD). The TOpClass consortium recently defined radiological healing (TOpClass-RH) by the absence of T2 hyperintensity, a completely fibrotic fistula tract, and absence of contrast enhancement when used. This study aimed to validate TOpClass-RH in real-world clinical practice.
Methods:
VALIDATE-PERIANAL was a retrospective, multi-centre international study. 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-RH 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 (Cohen’s kappa) and rates of proctectomy and stoma formation.
Results:
Of 977 patients screened, 40 with pfCD met inclusion criteria;14/40 (35%) fulfilled TOpClass-RH criteria. Sustained clinical remission was achieved in 93% of TOpClass-RH patients. Clinical recurrence occurred in 1/14 (7%) of TOpClass-RH patients versus 8/26 (30.8%) in the non-RH group (RR 4.3 [0.60–31.0], p=0.12), with a median follow-up of 28 months. Inter-rater reliability was excellent (κ 0.89–0.95). There was a trend toward lower rates of proctectomy and stoma formation in the TOpClass-RH group.
Conclusion:
TOpClass-RH was associated with sustained clinical remission, although the study was underpowered to detect statistically significant differences. The definition demonstrated excellent inter-rater reliability, supporting TOpClass-RH as a clinically meaningful radiological endpoint for trials and diagnostic stratification in pfCD. Larger prospective studies are required.
Radiological healing on MRI is the ultimate therapeutic goal in Class 2a perianal fistulising Crohn’s disease (pfCD). The TOpClass consortium recently defined radiological healing (TOpClass-RH) by the absence of T2 hyperintensity, a completely fibrotic fistula tract, and absence of contrast enhancement when used. This study aimed to validate TOpClass-RH in real-world clinical practice.
Methods:
VALIDATE-PERIANAL was a retrospective, multi-centre international study. 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-RH 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 (Cohen’s kappa) and rates of proctectomy and stoma formation.
Results:
Of 977 patients screened, 40 with pfCD met inclusion criteria;14/40 (35%) fulfilled TOpClass-RH criteria. Sustained clinical remission was achieved in 93% of TOpClass-RH patients. Clinical recurrence occurred in 1/14 (7%) of TOpClass-RH patients versus 8/26 (30.8%) in the non-RH group (RR 4.3 [0.60–31.0], p=0.12), with a median follow-up of 28 months. Inter-rater reliability was excellent (κ 0.89–0.95). There was a trend toward lower rates of proctectomy and stoma formation in the TOpClass-RH group.
Conclusion:
TOpClass-RH was associated with sustained clinical remission, although the study was underpowered to detect statistically significant differences. The definition demonstrated excellent inter-rater reliability, supporting TOpClass-RH as a clinically meaningful radiological endpoint for trials and diagnostic stratification in pfCD. Larger prospective studies are required.
Date Issued
2026-12-01
Date Acceptance
2026-03-09
Citation
Insights into Imaging, 2026, 17 (1)
ISSN
1869-4101
Publisher
SpringerOpen
Journal / Book Title
Insights into Imaging
Volume
17
Issue
1
Copyright Statement
© The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Identifier
10.1186/s13244-026-02260-1
Subjects
Fistula
Crohn's disease (perianal)
Colorectal imaging
MRI
Education
Publication Status
Published
Article Number
ARTN 90
Date Publish Online
2026-04-07