Abstract Background Transperineal ultrasound (TPUS) is increasingly used to assess distal rectal inflammation and perianal complications in inflammatory bowel disease (IBD). However, indications, technical protocols, activity thresholds, and response criteria remain heterogeneous across centres. This study aimed to develop an international expert consensus on the clinical role, standardised technique, and reporting framework for TPUS in IBD. Methods An international multidisciplinary panel of TPUS, intestinal ultrasound, and IBD experts participated in a structured Delphi process. Two online voting rounds were followed by iterative refinement of statements. Panellists rated agreement on a 5-point Likert scale and assigned evidence levels (high/moderate/low) based on the published literature and expert experience. A priori, consensus was defined as ≥ 80% of respondents voting “agree” or “strongly agree”. Participants were allowed to abstain from voting on any statement. Statements that did not reach consensus were revised or discarded. Results In total, 40 experts from Europe, Asia, North America, and Oceania completed ≥1 voting round. Overall, 30 statements across 19 domains achieved consensus (see Table). Key domains included: (i) clinical role of TPUS in ulcerative colitis (UC), pouchitis, and perianal disease in Crohn’s disease (pCD); (ii) standardisation of probe choice, preparation, and patient positioning; (iii) required scan planes by indication; (iv) orientation conventions and rectal bowel wall thickness (BWT) measurement; (v) Doppler settings for low-flow detection; (vi) TPUS activity thresholds and remission definitions for rectal UC (including adult and paediatric cut-offs); (vii) classification and reporting of pCD (Parks/AGA ± TOpClass); (viii) integration with MRI/TRUS; (ix) pragmatic follow-up schedules; and (x) minimum reporting datasets and safety triggers. Most final statements reached ≥90% agreement, while evidence levels ranged from low (technical parameters, follow-up cadence) to high (classification frameworks, MRI indications). Conclusion This international Delphi process provides comprehensive expert consensus on TPUS in IBD, defining its clinical role and standardising core technical, interpretive, and reporting elements. These statements offer a practical framework for implementing TPUS in routine care and mulicentre studies. Conflict of interest: Sagami, Shintaro: Shintaro Sagami has served as an advisory board member, consultant, or speaker for AbbVie, Alimentiv, Bristol Myers Squibb, Celltrion, EA Pharma, Eli Lilly, Ferring Pharmaceuticals, Gilead Sciences, Janssen Pharmaceuticals, Kyorin Pharmaceutical, Mitsubishi Tanabe Pharma, Mochida Pharmaceutical, Nippon Kayaku, Pfizer, Takeda, and Zeria Pharmaceutical, and has received research funding from Bristol Myers Squibb, EA Pharma, Gilead Sciences, Helmsley Charitable Trust, JIMRO, Kyorin Pharmaceutical, Miyarisan, Mochida Pharmaceutical, Nippon Kayaku, Pfizer, Sekisui Medical, Samsung, Takeda, and Zeria Pharmaceutical. Verstockt, Bram: Shintaro Sagami has served as an advisory board member, consultant, or speaker for AbbVie, Alimentiv, Bristol Myers Squibb, Celltrion, EA Pharma, Eli Lilly, Ferring Pharmaceuticals, Gilead Sciences, Janssen Pharmaceuticals, Kyorin Pharmaceutical, Mitsubishi Tanabe Pharma, Mochida Pharmaceutical, Nippon Kayaku, Pfizer, Takeda, and Zeria Pharmaceutical, and has received research funding from Bristol Myers Squibb, EA Pharma, Gilead Sciences, Helmsley Charitable Trust, JIMRO, Kyorin Pharmaceutical, Miyarisan, Mochida Pharmaceutical, Nippon Kayaku, Pfizer, Sekisui Medical, Samsung, Takeda, and Zeria Pharmaceutical. Allocca, Mariangela: Personal Fees: consulting fees from Nikkiso Europe, Mundipharma, Janssen, Abbvie, Pfizer, Ferring, Galapagos, Sandoz, Lilly and Alfasigma Pal, Partha: Partha Pal received consultancy fees/speaker honorarium from Johnson and Johnson, Takeda Pharmaceutical Company, Cipla Ltd, Sun Pharma, Zydus Biosciences, Dr Reddy Labs, Abbott India, RPG Life sciences, La Renon Healthcare Pvt Ltd and Daewoong Pharma Dal Buono, Arianna: No conflict of interest Christensen, Britt: No conflict of interest Albshesh, Ahmad: No conflict of interest Carter, Dan: No conflict of interest Lu, Cathy: No conflict of interest de Voogd, Floris: No conflict of interest Fraquelli, Mirella: No conflict of interest Seidelin, Jakob Benedict: No conflict of interest Blunt, Heather: No conflict of interest Vitale, Elaina: No conflict of interest Winter, Michael: No conflict of interest
Sagami et al. (Thu,) studied this question.