Young Investigator: Is Contrast-Enhanced Ultrasonography the Best Non-invasive Method to Evaluate Ileal Crohnʼs Disease Activity?

Abstract

BACKGROUND: Contrast-enhanced ultrasonography (CEUS) is an imaging technique that has been used to monitor patients with Crohn's Disease (CD). Our aim was to determine the performance of conventional US and CEUS and other non-invasive parameters such as clinical activity and analytical biomarkers to detect ileal CD inflammatory activity assessed by ileocolonoscopy. METHODS: Thirty patients with known ileal CD were evaluated. All patients underwent a conventional US followed by a CEUS using a microbubble contrast agent (SonoVue®). US examinations was performed using a Hitachi HI VISION Avius®, employing a linear abdominal transducer. Qualitative and quantitative parameters from the sonographic analysis included maximum bowel wall thickness, vascularity pattern by Doppler US and quantitative measurements of contrast bowel wall enhancement using CEUS (peak intensity and time to peak). Disease small bowel activity was assessed by ileocolonoscopy (reference) and patients were graded as inactive (normal or mild disease) or active (moderate or severe inflammation). Clinical disease activity was assessed by the Harvey–Bradshaw Index (HBI). Fecal calprotectin (FC) and C reactive protein (CRP) were performed within 1 week from CEUS and correlated with ileal inflammatory activity assessed by ileocolonoscopy. RESULTS: Endoscopic disease severity was as follow: normal or mild in 14 patients (46.7%), moderate or severe in 16 patients (53.3%). Sixteen patients (53.3%) had significant clinical activity (HBI≥5 points). No association was found between clinical activity by HBI and endoscopic disease activity (P=0.77). In patients with moderate and severe endoscopic activity, mean FC tended to be higher than in patients with inactive disease, but the difference was not statistically significant (878.6 μg/L vs 809.6 μg/L, P=0.78). No association was found between mean CRP and endoscopic activity (23.1 vs 23.9, P=0.95). In patients with active endoscopic disease, wall bowel thickness of the terminal ileum was higher than in patients with inactive disease, but this result was not statistically significant (6.5 mm vs 5.7 mm, P=0.33). No association was found between the presence of moderate to severe vascularity by Doppler (P=0.15), loss of normal stratification of the bowel wall (P= 0.596), mesentery hypertrophy (P= 0.69), mesenteric lymph nodes (P= 0.34) and disease activity. For CEUS, the peak intensity was related with disease severity (19.2 vs 8.7, P=0, 01) with a good capability to predict endoscopic activity in ileoscopy (area under the ROC curve 0.8, 95% CI 0.63-0.96). The time to peak could not predict endoscopic activity in ileoscopy (21.4 sec vs 20.9 sec, P=0.78). CONCLUSION(S): Clinical and analytical parameters are not sufficient to predict endoscopic activity in the terminal ileum. Conventional US is also not capable to predict endoscopic activity, being contrast-enhanced US an excellent non-invasive method for this purpose. CEUS peak intensity is a non-invasive and valuable parameter for an accurate detection of ileal inflammatory activity in CD leaving open, in the future, the possibility to monitor the therapeutic response.