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P149 Intestinal perfusion measurements with contrast-enhanced ultrasound and dynamic contrast-enhanced magnetic resonance imaging enterography: A comparison study

R. Wilkens*1, 2, D.A. Peters3, A.H. Nielsen1, V.P. Hovgaard1, H. Glerup1, K. Krogh2

1Silkeborg Regional Hospital, Diagnostic Centre, University Research Clinic for Innovative Patient Pathways, Silkeborg, Denmark, 2Aarhus University Hospital, Department of Hepatology and Gastroenterology, Aarhus C, Denmark, 3Aarhus University Hospital, Department of Clinical Engineering, Aarhus, Denmark

Background

Objective measures of disease activity in Crohn’s disease (CD) are necessary. Change in perfusion is a potential biomarker for treatment response, however studies confirming robustness/applicability of perfusion techniques are lacking in CD.

Study aims: repeatability assessment for dynamic contrast-enhanced ultrasound (CEUS) parameters measured within the thickened bowel wall of patients with active CD, and comparison of these initial time-intensity curve parameters with dynamic contrast-enhanced magnetic resonance imaging (MRI) enterography (DCE-magnetic resonance enterography [MRE]).

Methods

In total, 25 patients with moderate-to-severe CD underwent both DCE-MRE and CEUS within a week. SonoVue (2x2.4 ml) was injected before axial and longitudinal scans of the most inflamed bowel segment. CEUS was quantified with ‘Vuebox’ (Bracco). Up to 4 regions of interests were drawn with size > 0.1 cm2. DCE-MRE using gadolinium in a dynamic T1-sequence (VIBE) was analysed using an in-house developed programme. CEUS intensity data were log-converted before analysis, and regression analysis and limits of agreement (LoA) were computed.

Results

CEUS was successfully performed in 23 patients. In 14 patients, quality of fit > 85% allowed comparison between scan planes. Further, 95% LoA were -3.8 to 5.3 dB for peak enhancement and -3.3 to 4.6 dB/s for the area under curve. Limits were significantly improved by adding criteria that are stricter for quality of fit. Comparing CEUS and DCE-MRE, statistically significant correlation was found for the area under curve (p < 0.05) and maximum wash-in rate (p < 0.01), but not peak enhancement (p = 0.083). Good interrater variability was found between ultrasound and MRE for bowel wall thickness, intraclass correlation coefficient (ICC) = 0.71 (0.44–0.86, p < 0.0001), and length of disease, ICC = 0.89 (0.76–0.95, p < 0.0001).

Figure 1. Correlation between dynamic contrast enhanced MR enterography and contrast-enhanced ultrasound: wash-in rate.

Figure 2. Limits of agreement for bowel wall thickness. Left: Between ultrasonography and MRI enterography (MRE). Right: between two MRE observers.

Conclusion

CEUS has acceptable repeatability in active CD. The correlation CEUS and DCE-MRE suggests that CEUS could be a bedside alternative to MRI in CD treatment.