Editorial: Intestinal Ultrasound for the Assessment of Constipation—Out of the Shadows?

Abstract

Constipation is a common disorder of gut-brain interaction (DGBI) affecting both paediatric and adult populations [1, 2]. Although Rome IV criteria are the gold standard, diagnosing a patient with constipation can be challenging due to the non-specific nature of its symptoms and the overlap with other disorders. Diagnostic tools—such as digital rectal examination or radiologic modalities including abdominal X-ray, CT scan, or MRI—are invasive and come with high costs or significant radiation exposure [3]. This highlights the unmet need for a non-invasive, objective approach to assess constipation and faecal loading.

Intestinal ultrasound (IUS) is emerging as an ideal point-of-care tool, with a growing body of evidence supporting its use in monitoring inflammatory bowel disease [4]. More recently, its potential application has expanded to include the evaluation of DGBI, particularly constipation [5, 6]. However, standardised sonographic criteria for these conditions are lacking, and the diagnostic accuracy of IUS in constipation remains to be fully established.

To address this gap, a RAND/UCLA-modified Delphi consensus panel—comprising international experts in gastroenterology and radiology—integrated current evidence with expert opinion to develop guidance on the use of IUS in the evaluation of constipation [7]. The panel endorsed 43 statements supporting the use of IUS to assess luminal contents and colonic architecture. Notably, IUS was rated as an appropriate modality for detecting faecal loading across various colonic segments, including the rectum. In paediatric patients, the transverse rectal diameter was identified as a key metric: a diameter > 30 mm was considered predictive of faecal loading. This aligns with prior systematic reviews, although rectal size varies among children and is perhaps age- or sex-dependent [5]. Future implementation requires standardisation and assessment of reliability and reproducibility for adult and paediatric populations. In addition, a transperineal approach instead of an abdominal approach might increase accuracy, as has been demonstrated for ulcerative proctitis [8].

Additional sonographic features, including posterior acoustic shadowing, echogenic foci, and haustral loss, were considered useful in identifying faecal loading beyond the rectum. However, these features are not specific, as intraluminal gas may produce similar artefacts. This overlap introduces interpretation variability, particularly among less experienced operators. Although some studies have demonstrated concordance between IUS findings and CT imaging in detecting constipation-related features [9, 10], data remain limited. Further validation studies are needed to establish reliability against robust reference standards.

Despite current limitations, the potential of IUS in constipation assessment is substantial. Given the broad differential diagnosis and frequent need to exclude organic pathology, IUS could serve as an adjunctive tool to symptom-based criteria like Rome. That said, structural causes such as colonic strictures or malignancy must not be overlooked, and endoscopic evaluation remains the gold standard where clinically indicated.

In conclusion, while several questions remain regarding diagnostic accuracy and generalisability, the consensus work by Mathias et al. represents a meaningful step forward. In expert hands, IUS offers the potential for a more objective, scalable, and non-invasive approach for the assessment of constipation. Future prospective studies will be essential to refine diagnostic parameters and evaluate clinical outcomes in both paediatric and adult populations.

J. M. B. W. Vos: conceptualization, writing – review and editing, writing – original draft. M. A. Benninga: writing – review and editing. K. B. Gecse: writing – review and editing. F. A. E. De Voogd: writing – review and editing, conceptualization, writing – original draft, supervision.

This article is linked to Mathias et al. papers. To view these articles, visit https://doi.org/10.1111/apt.70250 and https://doi.org/10.1111/apt.70338.