Crohn Disease: Correlation of Findings at Contrast-enhanced US with Severity at Endoscopy

Purpose: To evaluate the effectiveness of visualization of vascularization at contrast material-enhanced ultrasonography (US) for assessment of the activity of Crohn disease, with severity grade determined at endoscopy as the reference standard. Materials and Methods: Ethics committee approval and written informed consent were obtained. Sixty-one patients (age range, 21-67 years; median age, 36 years) who had Crohn disease underwent both colonoscopy and US, including color Doppler and contrast-enhanced US, prospectively. To assess the vascularization of the involved bowel loop in a region expected to be seen at colonoscopy, the contrast agent uptake was measured by using quantitative analysis of the enhancement in regions of interest. Measurement of contrast enhancement was assessed as the increase in wall brightness with respect to the baseline brightness. Results were compared with the severity grade determined at endoscopy by using the area under the receiver operating characteristic curve and logistic regression analysis. Results: Colonoscopy showed inflammatory lesions in 53 patients (mild disease, seven; moderate disease, 12; and severe disease, 34). Bowel wall thickness and grade at color Doppler US (P = .019 and .002, respectively) correlated with severity grade at endoscopy. Mural contrast enhancement in patients with active disease at endoscopy was markedly increased in comparison with enhancement in patients with inactive disease (P = .001). Multivariate logistic regression analysis revealed that an increase in wall brightness was a significant and independent variable predictive of severity grade at endoscopy. A threshold brightness value of percentage of increase of 46% had a sensitivity and specificity of 96% and 73%, respectively, in the prediction of moderate or severe grade for inflammation at endoscopy. Conclusion: Quantitative measurements of bowel enhancement obtained by using contrast-enhanced US correlate with severity grade determined at endoscopy. Contrast-enhanced US could be a useful technique to monitor the activity of Crohn disease. (C) RSNA, 2009