What is Intestinal Ultrasound?
Intestinal ultrasound (IUS) is an imaging technique in which an ultrasound probe is placed on the outside of the abdomen and used to visualise the wall of the small and large intestine. Unlike colonoscopy, it does not require insertion of an instrument into the bowel, bowel preparation, or sedation; unlike CT or contrast-based MRI, it does not involve ionising radiation or contrast [1]. The bowel is examined for evidence of inflammation and complications including strictures (narrowed segments of bowel), abscesses (localised collections of infected fluid), and fistulae (abnormal channels connecting the bowel to nearby organs or skin) [2].
Intestinal Ultrasound in Inflammatory Bowel Disease Management
IUS has traditionally been used to assess inflammatory bowel disease (IBD), a group of chronic conditions in which inflammation affects the gut, the most common being Crohn's disease and ulcerative colitis. IUS has been used to guide IBD care in parts of Europe for well over a decade; in Italy and Germany, it has reportedly been incorporated into routine gastroenterology training and clinical pathways for several decades [3]. Use of IUS in the United States has grown substantially since 2020, coinciding with the availability of structured international training.
Uptake of IUS in Australia has been increasing, aided by the establishment of a national training and accrediting body, GENIUS. A 2026 survey found that 96% of Australian gastroenterologists surveyed considered IUS to represent standard of care in IBD management, with high ratings for its usefulness in both Crohn's disease and ulcerative colitis [3].
IUS is regarded as requiring fewer healthcare resources than colonoscopy or MRI, with shorter reported wait times, which may allow treatment decisions to be made sooner [3]. IUS findings also inform treatment decisions directly: a study of point-of-care IUS examinations from Amsterdam found that the scan result altered the treatment plan in 60% of consultations [4]. In a single-centre analysis of adults over 60 with IBD, introducing IUS was associated with reductions in subsequent endoscopy and contrast-enhanced CT or MRI [5].
Patient-reported experience data also favours non-invasive testing. A systematic review of people with IBD found that non-invasive tools, including IUS and faecal calprotectin (a stool-based marker of intestinal inflammation), were more often preferred over colonoscopy and other imaging [6].
IUS is an opportunity for education, with those undergoing IUS showing greater disease-related knowledge, with an associated increase in treatment adherence over time [6].
A 2026 umbrella review found that despite this growing clinical use, gaps do remain in the IUS evidence base for IBD with a need for validated, standardised disease-activity indices [7]. As always, further research is needed.
Emerging role in irritable bowel syndrome
More recently, IUS has been applied to non-IBD conditions such as irritable bowel syndrome (IBS) and related conditions now classified as disorders of gut–brain interaction (DGBI). DGBI are conditions defined by chronic gut symptoms such as abdominal pain, altered bowel habit, or bloating that occur in the absence of a structural or biochemical abnormality on standard testing. These conditions include chronic constipation and functional diarrhoea.
A 2024 systematic review identified 20 studies evaluating ultrasound in IBS, spanning bowel wall assessment, colonic motility, and gastric and gallbladder function; the authors concluded that ultrasound shows promise for distinguishing IBS from IBD and for grading symptom severity, while noting that further research is needed to standardise its use [8]. In 2021, a European expert panel recognised IUS as a tool for investigating dyspepsia, bloating, and altered bowel habit, beyond simply excluding structural disease [9]. Ultrasound assessment of colonic motility (the coordinated muscular contractions that move bowel contents along) is a newer and less-developed application [10].
In an Australian clinic that introduced ultrasound-based assessment for low-risk gastrointestinal symptoms, 86% of patients found the scan improved their understanding of their condition, and the scan was generally well tolerated [1].
Triaging low-risk patients through the ultrasound-supported clinic versus a historical cohort managed under the previous pathway was associated with a reduction in colonoscopy rate from 0.7 to 0.05 procedures per patient and a shorter median time to discharge (42 versus 125 days) [1].
In another Australian, dietitian-led clinic for DGBI, adding point-of-care IUS to standard assessment confirmed DGBI diagnosis in two thirds of patients, and prompted a change in management in 28% [11].
Symptoms do not always correlate with ultrasound findings. An Australian study of 88 patients with lower gastrointestinal symptoms, found that DGBI symptom categories predicted ultrasound findings only moderately well: 34% of patients categorised by constipation had no significant faecal loading on scan, while 27% of those with diarrhoea did [12]. In the dietitian-led clinic, IUS identified undiagnosed Crohn's disease in 3 of 97 patients, cases that would otherwise have been triaged as low risk based on the standard referral information alone [11]. IUS helped distinguish overflow diarrhoea, a pattern in which liquid stool leaks around a blockage of hardened stool, from diarrhoea due to other causes. Correctly identifying this pattern matters clinically, because treatments aimed at diarrhoea may worsen symptoms if the underlying problem is constipation with overflow [11]. An international, multidisciplinary expert panel similarly judged IUS an appropriate modality for evaluating faecal loading, useful in assessing overflow diarrhoea and other constipation-associated symptoms such as pain and bloating, while noting that supporting evidence remains limited, particularly in adults [13].
Intestinal Ultrasound Melbourne: Where does this leave us?
Taken together, the available evidence, drawn predominantly from cohort studies, clinician surveys, and expert consensus statements, with fewer randomised comparisons, suggests that IUS can provide information that changes clinical management in a meaningful proportion of patients with gut symptoms. IUS is generally well tolerated and is rated favourably by patients relative to alternative investigations, and may reduce the need for some subsequent endoscopic or cross-sectional imaging in selected settings.
IUS is well established in the assessment and monitoring of patients with inflammatory bowel disease. Its role in IBS and related disorders of gut–brain interaction is more recent and based on a smaller body of evidence, though early findings suggest it may be a useful adjunct to standard assessment. For general practitioners, this evidence may support considering referral for IUS-based assessment in patients with a change in bowel habit or suspected IBS, particularly where excluding IBD is a clinical priority, while recognising that access to IUS varies by region and by clinician training [3].
