Letter: Intestinal Ultrasound: The Evidence Is Catching Up With the Technology

We read with great interest the manuscript by Lu et al. who mapped the gaps in intestinal ultrasound (IUS) research [1]. Given the growing interest in this technology and its clinical application, we would like to congratulate the authors on their timely manuscript. However, we would like to emphasise that several of the gaps described by the authors are closing faster than the literature can track, and the emerging picture is more interesting than simple equivalence with endoscopy. Standardisation is a concern the authors rightly emphasised. An international consensus of 35 experts has now codified IUS response and remission criteria for clinical trials, endorsing the Bowel Ultrasound Score (BUSS) for Crohn's disease and the Milan Ultrasound Criteria (MUC) for ulcerative colitis [2]. The 2025 ECCO-ESGAR-ESP-IBUS guidelines formally recommend validated imaging indices for monitoring [3]. The scaffolding, in other words, is largely built. The deeper question is whether endoscopy itself sets the right benchmark. In ulcerative colitis, transmural healing independently predicted reduced relapse, yet the distinction between Mayo Endoscopic Subscore 0 and 1 did not [4]. Baseline MUC outperformed the Mayo score for predicting colectomy [5]. And ultrasound remission at week 12 was the sole independent predictor of sustained mucosal healing, carrying a 96% negative predictive value [6]. Crohn's disease tells a similar story. In a multicentre study, patients with sonographic inflammation despite clinical remission had higher corticosteroid use and reduced hospitalisation-free and surgery-free survival [7]. In another study by Castiglione et al., the authors found that transmural healing outperformed mucosal healing alone for 1-year clinical outcomes [8]. In a prospective study recently published in this journal, Yzet et al. followed patients who had already achieved complete endoscopic healing [9]. At 12 months, those with IUS transmural healing had a 2% relapse rate; those without, 33%. Absence of transmural healing was the only independent predictor of relapse. The temporal resolution of IUS is equally striking. In the STARDUST trial, patients with sonographic response at week 4 achieved superior transmural healing at 48 weeks [10]. This timing enables treatment optimisation before endoscopic reassessment would typically occur. Challenges remain: training pipelines are thin, access is uneven, and rectal imaging has real limitations. But the conversation has shifted. We are no longer simply asking whether IUS correlates with endoscopy. We are asking what transmural healing adds to mucosal healing and whether combining both perspectives might serve patients better than either alone. Luisa Bertin: methodology, validation, writing – original draft, investigation. Edoardo Vincenzo Savarino: conceptualization, investigation, writing – review and editing, supervision. The authors have nothing to report. Edoardo Vincenzo Savarino has served as speaker for Abbvie, Agave, AGPharma, Alfasigma, Aurora Pharma, CaDiGroup, Celltrion, Dr. Falk, EG Stada Group, Fenix Pharma, Fresenius Kabi, Galapagos, Janssen, JB Pharmaceuticals, Innovamedica/Adacyte, Malesci, MayolyBiohealth, Omega Pharma, Pfizer, Reckitt Benckiser, Sandoz, SILA, Sofar, Takeda, Tillots, Unifarco; has served as a consultant for Abbvie, Agave, Alfasigma, Biogen, Bristol-Myers Squibb, Celltrion, DiademaFarmaceutici, Dr. Falk, Fenix Pharma, Fresenius Kabi, Janssen, JB Pharmaceuticals, Merck & Co, Nestlè, Reckitt Benckiser, Regeneron, Sanofi, SILA, Sofar, Synformulas GmbH, Takeda, Unifarco; he received research support from Pfizer, Reckitt Benckiser, SILA, Sofar, Unifarco, Zeta Farmaceutici. Luisa Bertin declares no conflicts of interest. This article is linked to Lu et al. paper. To view this article, visit https://doi.org/10.1111/apt.70449. The authors have nothing to report.