Predicting the need for surgery in Crohn's disease with contrast harmonic ultrasound

Harmonic flash echo imaging (H-FEI), an intermittent scanning method using injection of Levovist, enables the evaluation of microperfusion of the gastrointestinal wall. The aim of this study was prospectively to investigate the relationship between bowel blood flow and the likelihood of the need for surgery in 70 patients with active Crohn's disease (CD), using conventional ultrasonography (US) and H-FEI.

For H-FEI, Levovist injection was followed by scanning of the bowel segment of interest with intermittent harmonic imaging for 2 min (interval, 4 s; transmission pulse at 2.3 MHz; reception at 4.6 MHz). We calculated the mean echo-intensity for the bowel wall showing strongest opacity in the FEI series for each patient. Maximum bowel-wall thickness, wall stratification, maximum echo-intensity obtained by H-FEI, CD activity index, and C-reactive protein concentration were compared between patients treated successfully with medication after H-FEI (group M) and those who proved to need surgery (group S).

No significant differences in clinical variables were evident between groups M (n=45) and S (n=25). The subsequent need for surgery was significantly indicated by multivariate analysis, showing loss of stratification in the bowel wall (odds ratio (OR)=5.98, 95% confidence interval (CI)=1.4-25.1, p=0.015) and high echo-intensity according to H-FEI (OR=1.02, CI=1.005-1.034, p=0.007).

In active CD, patients with bowel segments showing a loss of stratification and rich perfusion by H-FEI are likely to need surgical treatment.