Background and Aims: The submucosa is the most responsive bowel wall layer on intestinal ultrasound (IUS) when assessing treatment response in ulcerative colitis (UC). Submucosal thickening with hyper-echogenicity is observed. This study aimed to quantify echogenicity and understand transmural changes in UC. Methods: In total, 118 patients were studied in two cohorts. Cohort 1 included colectomy patients: 19 UC patients and 52 controls without inflammatory bowel disease. Cohort 2 included 47 UC patients in a prospective cohort starting anti-inflammatory treatment. In Cohort 1, submucosal inflammation, and fat and collagen deposition were scored by two pathologists using a semi-quantitative scale (0–3). For UC patients in Cohort 1, histopathology and IUS of the sigmoid were location matched. Relative submucosal echogenicity (RSE) was assessed, quantified in grayscale values. In Cohort 2, baseline sigmoid RSE was compared between endoscopic responders (≥1 point decrease in endoscopic Mayo score after 8–26 weeks) and non-responders. Results: In all colectomized UC patients with preserved wall layer stratification (n = 12, 63%), submucosal fat (score ≥1) was present; in those with loss of stratification (n = 7, 37%), fat was absent (score = 0). RSE was higher when fat was present [95.5 (IQR 86.5–116.9) vs 8.1 (IQR 5.8–23.0) grayscale values, P < .001], with no significant differences for inflammation and collagen. In Cohort 2, RSE was higher in non-responders (n = 17) compared to responders (137.1 ± 50.9 vs 88.3 ± 49.6 grayscale values, P = .003). An RSE of >108 grayscale values predicted non-response [OR: 0.07 (95% CI: 0.01–0.44), P = .004]. Conclusion: Submucosal hyper-echogenicity on IUS indicates fat deposition and predicts non-response in UC.

Background & Aims: Endoscopic healing (EH) is recognized as a long-term treatment goal for patients with ulcerative colitis (UC). We investigated whether transmural healing (TH) in UC as assessed by intestinal ultrasound (IUS) is associated with improved outcomes compared to EH alone. Methods: We performed a retrospective study in a tertiary center on patients with left-sided or extensive UC on stable maintenance treatment who had EH [Mayo Endoscopic Subscore (MES) ≤1) and an IUS performed within 6 months of an endoscopy with no treatment alterations between IUS and endoscopy. TH was defined as bowel wall thickness (BWT) <3 mm. The primary outcome was relapse-free survival in patients with and without TH. Results: A total of 61 patients (MES 0: 44.3%; MES 1: 55.7%) with a median follow-up of 20 months were included. On IUS, 72% of patients had TH. Twenty-three patients had a relapse (first-year relapse risk: TH: 7.5% vs no TH: 29.4%, P = .004; MES 0: 3.7% vs MES 1: 20.8%, P = .059). In multivariate Cox regression, female gender [hazard ratio (HR), 2.63; 95% CI 1.05–6.58; P = .039], two or more previous advance therapies (HR, 4.06; 95% CI 1.08–15.28; P = 0.038), and non-TH (HR, 3.99; 95% CI 1.31–12.20; P = .015) were associated with a relapse whereas EH level (MES 0 vs MES 1) was not an associated factor (HR, 1.06; 95% CI 0.32–3.55; P = .924) Conclusions: In UC patients TH is associated with lower relapse risk compared to EH alone. These findings imply that IUS is a non-invasive, low-cost alternative to endoscopy for stratifying UC patients for risk of relapse.

Background and Aims: Perianal complications such as fistulas and abscesses are common in Crohn’s disease (CD) and contribute to significant morbidity. Transperineal ultrasonography (TPUS) has emerged as a non-invasive and accurate method for perianal fistulizing CD (pfCD). This review evaluates the diagnostic accuracy of TPUS compared with magnetic resonance imaging (MRI), transrectal ultrasonography (TRUS), and examination under anesthesia (EUA) for detecting and classifying perianal fistulas and abscesses. Methods: A comprehensive literature search was conducted across multiple databases through January 2025 to identify studies evaluating TPUS accuracy in detecting perianal fistulas and abscesses compared with MRI, TRUS, or EUA as the reference standard. Meta-analysis was performed to assess TPUS accuracy for fistula detection (FD), fistula classification (FC), internal opening (IO) detection, and abscess detection (AD). The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to evaluate risk of bias. Results: Of 1059 studies identified, 29 were included in this review. Pooled sensitivities for FD (18 studies, 1474 patients), FC (11 studies, 585 patients), IO detection (six studies, 481 patients), and AD (16 studies, 1276 patients) were 97.5%, 80.3%, 89.6%, and 93.5% respectively while pooled specificities for FD, IO detection, and AD were 69.0%, 66.3%, and 94.5% respectively. The overall TPUS accuracy for FD, FC, IO detection, and AD was 88.0%, 88.6%, 77.8%, and 91.8% respectively. Subgroup analysis on CD patients showed an accuracy of 86.4%, 87.6%, and 83.3% for FD, FC, and AD respectively. Conclusions: TPUS demonstrates high accuracy in detecting perianal fistulas and abscesses, supporting its use as a non-invasive, first-line diagnostic tool.

Introduction: Intestinal ultrasound (IUS) is a promising tool for predicting treatment response in inflammatory bowel disease (IBD). We aimed to systematically review existing literature on the predictive value of IUS for treatment response. Methods: A literature search was performed until May 2025. We included articles assessing treatment response in IBD using IUS. Data were analyzed separately for Crohn’s Disease (CD), ulcerative colitis (UC) and acute severe ulcerative colitis (ASUC). Pooled data analysis was performed for bowel wall thickness (BWT) in CD patients starting anti-TNF (tumor necrosis factor). Results: In total, 31 articles were included (18 CD, 9 UC, and 4 ASUC). In 8/10 CD studies, IUS at week 4-8 could distinguish future responders, with BWT change ranging from −43% to −14.6% in responders vs. −14% to + 2% in nonresponders. In the pooled data analysis of anti-TNF-treated CD patients (n = 236) a 23% decrease from baseline at week 4-8 (area under the receiver operating characteristic curve [AUROC] 0.82) and 27% decrease at week 12-16 (AUROC 0.78) could predict future response. In 2/2 UC studies, IUS after 4-8 weeks could predict future endoscopic remission vs. non-remission with a decrease in BWT ranging from −55% to −49% vs. −38% to −17% respectively. In ASUC, change in BWT after 1-3 days could predict need for salvage therapy (−34% vs. −10%). Conclusions: Intestinal ultrasound predicts response at an early stage after treatment initiation, both in CD as well as in UC. In anti-TNF-treated CD patients, 23% and 27% decrease in BWT after 4-8 weeks and 12-16 weeks of treatment initiation predicts outcomes.

Background and Aims: A reduction of bowel wall thickness (BWT) on intestinal ultrasound (IUS) predicts endoscopic response in ulcerative colitis (UC). Advanced techniques such as shear-wave elastography (SWE) might enhance response assessment. We aimed to identify early IUS parameters to predict treatment response to filgotinib in UC. Methods: This prospective observational study included UC patients with endoscopically active disease (endoscopic Mayo score [EMS] ≥2, extending beyond the rectum) starting on filgotinib. IUS parameters, including SWE, were assessed at baseline (T0), week 4 (T1), and at second endoscopy (T2). EMS of both the most-affected segment and the sigmoid was assessed at T0 and T2, and endoscopic response was defined a ≥1 point decrease in EMS. Results: A total of 23 patients were included. Six of 21 patients who underwent a second endoscopy were endoscopic responders. At T1 in the sigmoid, a BWT decrease of ≥1.33 mm or ≥24.7% (odds ratio [OR]: 32.5 [2.4-443.2], P = .009 and OR: 13.8 [1.2-156.6], P = .035) and submucosa decrease of ≥20.8% (OR: 13.8 [1.2-156.6], P = .035) predicted endoscopic response. Additionally, color Doppler signal (CDS) improvement at T1 predicted endoscopic response (OR: 20.0 [1.7-241.7], P = .018). In the sigmoid, SWE values changed differently over time between responders and non-responders (T2: 9.9 ± 15.7 vs −8.1 ± 11.4 kPa, P = .002). However, SWE values at T1 were not predictive of endoscopic response (OR: 1.07 [0.99-1.16], P = .088). Conclusions: On IUS, BWT, submucosal thickness, and CDS predict endoscopic response after 4 weeks of filgotinib treatment. SWE values in the sigmoid differ between responders and non-responders, but early assessment does not predict treatment response.

Background and Aims: Point-of-care tests (POCT) enable immediate measurement of anti-TNF blood concentrations. This study examined the association between loss of response (LOR) to infliximab (IFX) or adalimumab (ADL) and serum concentrations measured with POCT and enzyme-linked immunosorbent assay (ELISA) in inflammatory bowel disease (IBD) patients. Methods: Patients with IBD with stored IFX or ADL serum samples were recruited. POCT was conducted, agreement with ELISA was evaluated using Bland–Altman plots. The primary endpoint was LOR defined as change in therapy, IBD-related surgery, new actively draining fistula, and/or endoscopic deterioration. ROC curves and quartile analysis assessed the association between concentrations and LOR. Results: A total of 176 patients were included (92 IFX/84 ADL, 154 Crohn’s disease, and 22 ulcerative colitis). Median follow-up time was 20 months (interquartile range 9-38). LOR occurred in 37/84 (44%) ADL users and 55/92 (60%) IFX users. Median serum concentrations were significantly lower in LOR patients compared with sustained response, measured by both techniques for ADL (POCT: 6.45 vs 13.48 µg/mL, P <.001; ELISA: 4.80 vs 8.80 µg/mL, P <.001) and IFX (POCT: 2.39 vs 6.50 µg/mL, P <.001; ELISA: 1.70 vs 4.40 µg/mL, P <.001). Quartile analysis revealed that higher serum concentrations were associated with maintained response. ROC curve analysis demonstrated good or excellent discrimination for POCT and ELISA in association with LOR (AUC IFX: POCT = 0.82, ELISA = 0.76; AUC ADL: POCT = 0.82, ELISA = 0.81; all P <.0001). An overestimation of serum concentrations with POCT was observed. Conclusions: Serum ADL and IFX POCT concentrations are comparable to ELISA and associated with LOR, indicating its clinical utility.