W1049 Quantification of Microvascular Activation in Ileal Crohn's Disease By Software Elaboration Data Applied to CEUS: Correlation with Biological Activity Indexes

Abstract

PURPOSE Microvascular activation and angiogenesis induced by inflammation in ileal loops affected by Crohn's disease (CD) can be demonstrated by contrast-enhanced wideband harmonic imaging ultrasound (CEUS) with second-generation intravascular contrast media (blood-pool). Aim of the present perspective study was to evaluate if Time To Peak (TTP), Maximum Peak Intensity (MPI) and Slope (Coefficient of the wash-in slope) (β ) are able to predict and quantify inflammatory activity in ileal CD. METHOD AND MATERIALS The study was performed by means of digital US scanner Philips iU22 with dedicated software for low-mechanical-index studies and a 4 to 8 MHz linear-array probe. Fifthy-four transabdominal US examinations with second generation contrast agent (SonoVue® i.v. 4,8 ml) were performed. After informed consent, between 2005 and 2007, fifthy-four consecutive patients (M38, F16, age range 18-69 years; mean 35) affected by ileal CD without colonrectal disease or with inactive colonic disease, were studied by CEUS. According to Montreal classification 16 patients had inflammatory, 17 stricturing and 21 penetrating disease The US data obtained after SV administration allow to draw up time-intensity curves through software-assisted HDI-QLab and to obtain following parameters: time to peak (TTP), maximum peak intensity (MPI) coefficient of the wash-in slope (β ). Through ROC curve analysis, quantitative data were correlated with Biological Activity as Gold Standard, that is the positivity of at least 3 beetweenCDAI, laboratory parameters, endoscopy, radiology. RESULTS In distinguish active disease, TTP (seconds) with a cut-off >8.1 showed sensitivity 97.2% specificity 77.7% (p=0.0001, AUC 0.86); MPI (Db), cut-off >24, sensitivity 97.2%, specificity 83.3% (p=0.0001, AUC 0.927); Slope (Db/sec), cut-off >4.5, sensitivity 86.1%, specificity 83.3%, (p=0.0001, AUC 0.891). CONCLUSION This study demonstrates that TTP, MPI and Slope are able to predict and quantify inflammatory activity in ileal CD. Quantitative CEUS and definite cut-off could improve the reliability of conventional US to detect active bowel wall inflammation in CD. Quantitative data could objectivate the response to the therapies. CEUS could be used in the follow-up because of lack of radiation exposure.