Abstract Background The METRIC study1 demonstrated that both intestinal ultrasound (IUS) and magnetic resonance enterography (MRE) are highly accurate in detecting small bowel (SB) disease presence (90%) and activity (92%). IUS was less sensitive for assessing disease extent (70%), particularly in patients with ‘complex disease’ (fistula, small bowel (SB) disease extent 20cm or proximal disease). We reviewed local MRE data to identify where IUS may have been an appropriate alternative based on disease distribution and predicted potential cost savings. Methods We included MREs performed for known or suspected Crohn’s Disease (CD) in 2022. Data were extracted retrospectively from CRIS®. We evaluated the proportion of patients in our cohort where IUS may have directed management. We identified a subgroup with ‘complex disease’, as defined, above and assessed whether the MRE result may have changed clinical decision making. We subsequently predicted potential cost savings. Results In 2022 our department requested 268 MREs for known (n = 177) or suspected (n = 91) CD. Disease activity was reported in 118/268 (44%) scans (13/92 14% suspected and 105/177 61% known CD). In patients with active disease, presuming similar sensitivity demonstrated in METRIC1, IUS may have detected true disease presence, extent and activity in 106/118 (90%) and 109/118 (92%) and 83/118 (70%) patients respectively. In 15/268 cases an MRE was required at the point of referral (complex disease or differential diagnosis). 35/253 remaining cases (14%) met our definition for ‘complex disease’ where IUS sensitivity is reduced. In 11/35 MRE findings altered clinical decision making (isolated proximal disease n = 7, surgical planning n = 4). 24/35 cases had active terminal ileitis (easily identifiable on IUS) where treatment escalation decisions would have been similar irrespective of disease extent. 242/253 (96%) were therefore deemed suitable for IUS at the outset with 223/242 (92% sensitivity) predicted to correctly identify activity (cost difference £11,150 vs £55,750). One incidental finding required gynaecological drainage (case identified as requiring MRE at the outset). 70% of known CD cases had several MREs (mean 2 range 1-7) over a median 4-year period reflecting cumulative cost savings over time. Conclusion We have identified potential cost savings to fund the purchase of an ultrasound machine. Without IUS access at the point of data collection, we merely predicted IUS adequacy in terms of disease distribution and have not accounted for several factors which may limit views (e.g. operator skill, BMI, pregnancy, disease severity). Prospective data collection is now underway to determine actualised cost savings. Reference: 1. Taylor SA, Mallett S, Bhatnagar G, et al. Diagnostic accuracy of magnetic resonance enterography and small bowel ultrasound for the extent and activity of newly diagnosed and relapsed Crohn’s disease (METRIC): a multicentre trial. Lancet Gastroenterol Hepatol 2018;3(8):548-558. (In eng). DOI: 10.1016/s2468-1253(18)30161-4. Conflict of interest: Dr. Davies, Isabella: No conflict of interest Meade, Susanna: Speaker fees FalkPharma, Abbvie Conference fees J and J Ad board J and J
Davies et al. (Thu,) studied this question.