Abstract Background Mucosal healing (MH) is widely recognized as the therapeutic target in treat-to-target strategies for ulcerative colitis (UC). Although colonoscopy is the gold standard for evaluating MH, its invasiveness and limited cost-effectiveness restrict frequent monitoring. Intestinal ultrasound (IUS) offers a non-invasive advantage, its sensitivity for evaluating MH remains limited. In this study, we integrated photoacoustic/ultrasound (PA/US) imaging with IUS as a novel approach to improve the accuracy of ultrasound assessment of MH. Methods This diagnostic accuracy study was conducted at PUMCH from June 2024 to October 2025. Consecutive adult patients (aged 18–75 years) with an established diagnosis of UC and documented disease extent of left-sided and extensive colitis were eligible for recruitment. Exclusion criteria included pregnancy, lactation, and a history of colectomy or intestinal malignancy. Within a 7-days window, all enrolled patients underwent a standardized assessment protocol consisting of colonoscopy, IUS and PA/US imaging. The Mayo endoscopic score (MES) was documented for each colon segment. MH was defined as a MES of 0. The index tests were the Milan Ultrasound Criteria (MUC) and MUC combined with PA imaging. The PA score was scored 1-3, based on the percentage of the bowel wall area occupied by the PA signal. The diagnositc value of the MUC alone and in combination with PA score for diagnosing MH were evaluated. Results A total of 32 patients with UC were included in the study, yielding 121 colonic segments for analysis. Seven segments were excluded from the final analysis: 1 was unobservable on ultrasound and 6 were unreachable during colonoscopy. The cohort consisted of 14 (43.8%) females, with a median age of 38 years (range 18–63). Across all assessed segments, 53 segments were scored MES of 0, 29 segments were scored 1, 13 and 12 segments were scored 2 and 3 respectively. The combination of MUC and PA score demonstrated showed a stronger correlation with MES compared to MUC alone (r = 0.56 vs r = 0.52). Receiver operating characteristic (ROC) curve analysis was performed to differentiate between a MES of 0 and score of 1. The model combining MUC and PA score showed superior diagnostic performance, with an area under the curve (AUC) of 0.68, compared to an AUC of 0.67 for MUC alone. Furthermore, the combined approach significantly increased the sensitivity for identifying MH from 44.8% to 65.5%, representing a 20.7% improvement. Conclusion The integration of PA imaging with established MUC strengthens its correlation with endoscopic disease activity and improves sensitivity for detecting MH. This multimodal, non-invasive approach shows promise for enhancing the clinical monitoring and management of UC. References: 1. Boal Carvalho P, Cotter J. Mucosal Healing in Ulcerative Colitis: A Comprehensive Review. Drugs. 2017;77(2):159-173. doi:10.1007/s40265-016-0676-y. 2. Attia ABE, Balasundaram G, Moothanchery M, et al. A review of clinical photoacoustic imaging: Current and future trends. Photoacoustics. 2019;16:100144. Published 2019 Nov 7. doi:10.1016/j.pacs.2019.100144. 3. Allocca M, Fiorino G, Bonovas S, et al. Accuracy of Humanitas Ultrasound Criteria in Assessing Disease Activity and Severity in Ulcerative Colitis: A Prospective Study. J Crohns Colitis. 2018;12(12):1385-1391. doi:10.1093/ecco-jcc/jjy107. 4. Allocca M, Filippi E, Costantino A, et al. Milan ultrasound criteria are accurate in assessing disease activity in ulcerative colitis: external validation. United European Gastroenterol J. 2021;9(4):438-442. doi:10.1177/2050640620980203. Conflict of interest: Prof. Dr. Li, Yue: No conflict of interest Zhu, Yalong: No conflict of interest Zhang, Rui: No conflict of interest Yun, Longxi: No conflict of interest Yang, Meng: No conflict of interest
Li et al. (Thu,) studied this question.