Intestinal ultrasound in inflammatory bowel disease: diagnostic accuracy and impact on clinical decision making in a New Zealand tertiary centre.

AIMS: We aimed to evaluate the diagnostic correlation between intestinal ultrasound (IUS) and follow-up investigations, and to describe the impact of IUS on clinical decision making, particularly point-of-care use.

METHODS

A retrospective audit of consecutive IUS examinations in Wellington Regional Hospital for inflammatory bowel disease (IBD) from December 2021 to February 2025 was conducted. Follow-up investigations (faecal calprotectin [FCP], endoscopy, cross-sectional imaging or repeat IUS) within 6 months were collated and correlation assessed using two pre-specified composites, using two FCP thresholds: a conservative cutoff of <50mcg/g and a more liberal threshold of <150mcg/g.1 Additional outcomes included decision-altering impact and time to decision.

RESULTS

We analysed 373 IUS examinations in 253 patients (89.5% Crohn's disease [CD]; 34.6% point-of-care). IUS directly altered clinical decisions in 134/373 (35.9%), with 70/134 (52.2%) decisions made the same day. Follow-up occurred after 160/373 scans (42.9%). Excluding five "not commentable" scans, correlation was 141/155 (91.0%) using FCP <150mcg/g and 128/155 (82.6%) using FCP <50mcg/g.

CONCLUSION

In this real-world New Zealand cohort, IUS correlated strongly with follow-up investigations, particularly using an FCP <150mcg/g threshold, and frequently altered management, often on the same day. These findings support wider implementation of IUS as a radiation-sparing, point-of-care monitoring tool in New Zealand.