Abstract Background Intestinal ultrasound (IUS) is a non-invasive, point-of-care modality to assess disease activity and extent in inflammatory bowel disease (IBD). A longstanding concern is that higher body mass index (BMI) may impair visualization due to increased abdominal wall thickness and ultrasound beam attenuation, and real-world IUS studies have identified abdominal adiposity as a contributor to inconclusive examinations. However, systematic evidence quantifying the effect of BMI on IUS performance in IBD is limited. We aimed to assess whether BMI affects bowel visualization in clinical IUS practice. Methods We retrospectively analyzed IUS scans at a tertiary IBD centre (August 2021-August 2025). Successful visualization was defined by the ability to obtain a bowel wall thickness (BWT) measurement, which considered one of the most reliable indicators of active inflammation. Scans were acquired by three experienced bowel sonographers using standardized protocols. Rectal visualization was assessed in a predefined subgroup (n = 135). Visualization rates of bowel segment and BMI category (18, 18–25, 25–30, ≥30 kg/m²) were compared using the Freeman-Halton test. Results A total of 748 scans from 516 patients (median age 43 years IQR 32-59, 50% female, median BMI 24.9 22.1–28.6) were included. Among those with native anatomy (n = 589), the terminal ileum (TI), colonic segments, and rectum were visualized consistently across BMI groups with no significant difference. Among patients with prior ileocecal resection (n = 159), there was no significant difference in anastomosis visualization across BMI groups (p = 0.05). In patients with ileal Crohn’s disease (n = 269), TI visualization was ³93.6% across all BMI groups (p = 0.63). In IBD patients without ileal disease (n = 318), visualization did not differ significantly across BMI groups (p = 0.15). However, a significant difference was observed in the overweight group between IBD cases involving the TI and those sparing it (97.7% vs 85.5%, p = 0.005). Analysis using only the last scan per patient (n = 516) confirmed these findings. Conclusion IUS visualization of bowel segments and anastomoses was consistent across BMI categories. Visualization was more influenced by disease location than BMI, underscoring the robustness of IUS across body habitus. Conflict of interest: Maracle, Brooke: No conflict of interest Hazra, Deepan: No conflict of interest Novak, Kerri L.: Consultant for Pfizer, Abbvie, Eli Lilly and Pendopharm, and speaker for Takeda. Lu, Cathy: Advisory board - Abbvie, JnJ, Takeda, Ferring, Merck, Celltrion, Pfizer Research Funding - Abbvie, JnJ Besney, Jonathan: No conflict of interest Reji, Rohita: No conflict of interest Aldarwish, Alia: No conflict of interest Kaplan, Gilaad: Grant: Dr. Kaplan received grants for research from Ferring and for educational activities from AbbVie, Bristol Myers Squibb, Ferring, Fresenius-Kabi, Janssen, Pfizer, Takeda. Personal Fees: Dr. Kaplan has received honoraria for speaking or consultancy from AbbVie, Amgen, Janssen, Pfizer, and Takeda. Seow, Cynthia: Travel support from AbbVie, advisory board from Pfizer and speaker’s fees from Takeda. Ma, Christopher: Consulting fees: AbbVie, Alimentiv, Amgen, Anaptys Bio, AVIR Pharma Inc, Bristol Myers Squibb, Celltrion, Domain Therapeutics, Eupraxia, Eli Lilly, Ferring, Forte Biosciences, Fresenius Kabi, Gilead, Janssen, McKesson, Merck, Mirador Therapeutics, Pendopharm, Pfizer, Roche, Sanofi, Takeda, Tillotts Pharma Speaker’s fees: AbbVie, Amgen, AVIR Pharma Inc, Alimentiv, Bristol Myers Squibb, Eli Lilly, Ferring, Fresenius Kabi, Janssen, Merck, Organon, Pendopharm, Pfizer, Sanofi, Takeda, Tillotts Pharma Royalties: Springer Publishing Research Support: AbbVie, Eli Lilly, Ferring, Pfizer Ingram, Richard James Michael: Consultant for Pfizer, Abbvie, Eli Lilly and Pendopharm, and speaker for Takeda. Panaccione, Remo: Grant: Abbvie, Janssen, Pfizer, Takeda Other: Consultant for: Abbott, AbbVie, Abbivax, Alimentiv (formerly Robarts), Amgen, AnaptysBio, Arena Pharmaceuticals, AstraZeneca, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Celltrion, Cosmos Pharmaceuticals, Eisai, Elan, Eli Lilly, Ferring, Galapagos, Fresenius Kabi, Genentech, Gilead Sciences, Glaxo-Smith Kline, JAMP Bio, Janssen, Merck, Mylan, Novartis, Oppilan Pharma, Organon, Pandion Pharma, Pendopharm, Pfizer, Progenity, Prometheus Biosciences, Protagonist Therapeutics, Roche, Sandoz, Satisfai Health, Shire, Sublimity Therapeutics, Spyre Therapeutics, Takeda Pharmaceuticals, Theravance Biopharma, Trellus, Union Biopharma, Viatris, Ventyx, UCB Speaker’s Fees for: AbbVie, Amgen, Arena Pharmaceuticals, Bristol-Myers Squibb, Celgene, Eli Lilly, Ferring, Fresenius Kabi, Gilead Sciences, Janssen, Merck, Organon, Pfizer, Roche, Sandoz, Shire, Takeda Pharmaceuticals Advisory Boards for: AbbVie, Alimentiv (formerly Robarts), Amgen, Arena Pharmaceuticals, AstraZeneca, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Eli Lilly, Ferring, Fresenius Kabi, Genentech, Gilead Sciences, Glaxo-Smith Kline, JAMP Bio, Janssen, Merck, Mylan, Novartis, Oppilan Pharma, Organon, Pandion Pharma, Pfizer, Progenity, Protagonist Therapeutics, Roche, SandozShire, Sublimity Therapeutics, Takeda Pharmaceuticals, Ventyx. Dr. St-Pierre, Joelle: Consulting: Pfizer, Abbvie, Pendopharm, Eli Lilly. Speaker fees: Takeda, Pfizer.
Maracle et al. (Thu,) studied this question.