Intestinal ultrasound (IUS) may help predict treatment response early in inflammatory bowel disease (IBD) — both in Crohn’s disease and ulcerative colitis. Findings from a systematic review and pooled analysis published in the Journal of Crohn’s and Colitis suggest that the noninvasive, cost-effective, point-of-care imaging modality could support clinical decision-making.
“Choosing the right treatment in an early stage of disease is pivotal to prevent disease progression and long-term complications,” wrote lead author Johanna M.B.W. Vos, BSc, of the University of Amsterdam, the Netherlands, and colleagues.
“There are no predictive markers of treatment response, and therefore the choice of treatment is often based on a trial-and-error approach," noted researchers. IUS has shown promise as an objective indicator, although the relevance of different parameters, thresholds, and their predictive values had not been previously specified.
In the pooled analysis of their study, decreases in bowel wall thickness of at least 25% after four to eight weeks and 12 to 16 weeks of anti–tumor necrosis factor (TNF) therapy appeared to accurately predict response in patients with Crohn’s disease, elucidating the value of B-mode IUS parameters.
Study details
The researchers searched PubMed, MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and CINAHL from database inception through May 2025 for studies assessing treatment response in IBD using IUS. Of 3,703 records identified, 31 studies (18 Crohn’s disease, 9 ulcerative colitis, and 4 acute severe ulcerative colitis) were included.
Data were analyzed separately by disease category. Pooled analysis of bowel wall thickness was performed in patients with Crohn’s disease initiating anti-TNF therapy (n=236); raw data on bowel wall thickness and treatment response were obtained from studies including at least five such patients.
Predictive value of IUS
In 8 of 10 Crohn’s disease studies, IUS at four to eight weeks showed predictive value in distinguishing future responders, with bowel wall thickness changes between −43% and −14.6% in responders and between −14% and +2% in nonresponders. Based on the pooled analysis of anti-TNF–treated patients with Crohn’s disease, a 23% decrease from baseline in bowel wall thickness at four to eight weeks (area under the receiver operating characteristic curve [AUROC]=0.82) and a 27% decrease at 12 to 16 weeks (AUROC=0.78) appeared to be associated with future response.
In both ulcerative colitis studies examined, the researchers found that IUS after four to eight weeks could predict future endoscopic remission, with reductions in bowel wall thickness ranging from −55% to −49% in patients who achieved this outcome and from −38% to −17% in those who did not.
Changes in bowel wall thickness after one to three days seemed to be associated with the need for salvage therapy in acute severe ulcerative colitis (−34% vs −10%).
Clinical considerations
The researchers noted several limitations, including substantial heterogeneity across studies, particularly in IUS timing and outcome definitions. While all studies reported bowel wall thickness, fewer assessed other IUS parameters (e.g., color Doppler signal, bowel wall stratification, inflammatory fat), limiting broader evaluation. They were also unable to correct for treatment type, disease location, or duration.
To better define the optimal thresholds and time points of IUS to predict response, the researchers noted the need for large, multicenter studies in Crohn’s disease and ulcerative colitis. These studies should include multiple therapies, account for disease location, use predefined time points and uniform outcome definitions, and analyze outcomes by treatment type, they explained. Incorporating standardized IUS parameters and implementing IUS scores may improve predictive value.
In summarizing their findings, the researchers concluded, “This systematic review provides a comprehensive overview of the predictive role of IUS following treatment initiation in IBD, showing that IUS can predict response already at an early stage after treatment initiation, both in Crohn’s disease as well as in ulcerative colitis," the researchers concluded.
Ms. Vos reported no conflicts of interest. Full disclosures for the remaining authors are available in the published study.