Effectiveness of contrast-enhanced ultrasound for characterisation of intestinal inflammation in Crohn's disease: a comparison with surgical histopathology analysis

Background: Differentiation between predominantly inflammatory versus fibrous-predominant lesions is particularly important in order to decide the optimal therapy in patients with refractory symptoms in Crohn's disease (CD).

Objective: The purpose of this investigation was to evaluate the accuracy of several US parameters, especially of contrast-enhanced US, for evaluation of mural inflammation in CD, with histopathology as the reference.

Materials and methods: Preoperative ultrasound examination, including contrast-enhanced ultrasound (CEUS) was performed in 25 consecutive patients with Crohn's disease undergoing elective bowel resection. Ultrasound variables, such as wall thickness, transmural complications, colour Doppler grade, quantitative analysis of the enhancement and the presence and severity of strictures, were prospectively evaluated and compared with the histopathology results. Histopathology grading of acute inflammation using the acute inflammatory score and the degree of fibrostenosis was performed in each segment and the results were compared with all the US variables as well as with a previously defined ultrasound score system for inflammatory and fibrostenotic changes.

Results: 28 segments were analysed. In pathology analysis there were 12 predominantly inflammatory segments, 9 predominantly fibrostenotic and 7 compound lesions. When the pathology score was dichotomised into two groups (inflammatory and fibrostenotic) the number of stenoses correctly classified by US was 23 out 28, with a substantial agreement (kappa=0.632). There was a good correlation between the sonographic and pathology scores, both inflammation (Spearman's, r=0.53) and fibrostenosis (Spearman's, r=0.50). Transmural complications, colour Doppler grade and percentage of increase in contrast enhancement were significantly associated with the pathology inflammatory score (p=0.018, p=0.036 and p=0.005, respectively). There was a significantly negative association between the colour Doppler grade and the pathologic fibrostenotic score.

Conclusions: Ultrasound, including CEUS, can be a useful tool for distinguishing inflammatory from fibrostenotic lesions in CD. This information can be useful in the management of CD.