Predictive value of time–intensity curves obtained with contrast-enhanced ultrasonography (CEUS) in the follow-up of 30 patients with Crohn's disease

Abstract

Objectives CEUS can provide accurate quantitative estimates of intestinal wall microvascularization in Crohn's disease. We hypothesized that inflammation of the intestinal wall is correlated not with the amount of wall vascularization (study of vascularization patterns, SVP) but with the degree of wall flow during a period of time (time–intensity study, TIS). Our objective was to discover whether CEUS SPV and/or CEUS-TIS reflect(s) vascular inflammation of the intestinal wall and display(s) correlation with clinical activity of the disease at the time of the examination (T0) or at the 3- and 6-month follow-up (T3, T6). Materials and methods 30 patients with Crohn's disease (12 men, 18 women, mean age: 41.96 years; treatment: 5-ASA ( n = 8), steroids ( n = 13), anti-TNF ( n = 7), azathioprine ( n = 2) were studied with CEUS SPV and CEUS-TIS and followed for at least 6 months. The sonographic examinations were performed with SonoVue (BR1, Bracco) and a dedicated scanner (TECHNOS MPX, Esaote) equipped with software for calculation of time–intensity curves. Four vascular patterns (1: vascularization of the entire wall; 2: vascularization of >50% of the wall; 3: flow exclusively within the submucosal layer; 4: no signal). The semiquantitative analysis consisted in measurement of the area under the curve (AUC) (cut-off between active and inactive disease, 15), mean intesnity (IMA) (cut-off = 10). Each examination (180 s) was digitally recorded and analyzed. Results T0: cDAI <150 in 22 pts; cDAI > 150 in 8; T3: 22 pts. with cDAI<150, 8 with cDAI >150. At T0 CEUS SPV and CEUS-TIS both displayed low specificity, diagnostic accuracy, and negative predictive values ( p = ns). At T0, CEUS SPV produced 8 true positives (TP), 15 true negatives (TN), 8 false positives (FP), 0 false negative (FN) (sensitivity: 100%; specificity: 68.2%; diagnostic accuracy: 69.5%; Positive predictive value (PPV): 100%; negative predictive value (NPV: 53.3%), and CEUS-TIS produced 6 TP, 18 TN, 4 FP, 2 FN (sensitivity 75%; specificity: 81.8%; diagnostic accuracy: 75%; PPV: 60%; NPV: 90%). At T3, CEUS SPV produced 8 TP, 12 TN, 7 FP, 3 FN (sensitivity: 72.7%; specificity: 63.2%; diagnostic accuracy: 50%; PPV: 53.3%; NPV: 80%), and CEUS SIT produced the following results: 10 TP, 19 TN, 0 FP, 1 FN (sensitivity: 90,9%; specificity: 100%; diagnostic accuracy: 96,5%; PPV: 100%; NPV: 95%). At T3 CEUS-SVP displayed low sensitivity and low diagnostic accuracy, whereas SIT was able to predict clinical activity during follow-up in all but one case (which showed reactivation after 6 months) ( p = 0.001) Conclusion CEUS-TIS alone was found to reflect vascular inflammation of the intestinal wall in Crohn's disease and predicted clinical activity during follow-up.