The value of pre- and post-contrast-enhanced ultrasound in evaluation of malignant potential of gastrointestinal stromal tumors

Background: Contrast-enhanced ultrasound (CEUS) permits evaluation of intratumoral vascularity in real time. The purpose of the present study was to compare the performance of conventional ultrasound (US) and CEUS in the evaluation of malignancy risk in patients with gastrointestinal stromal tumors (GISTs).Methods: In this retrospective study, we included patients with suspected GISTs who underwent conventional US and CEUS preoperatively. Fifty patients with pathologically confirmed GISTs were enrolled. Tumor risk stratifications were determined according to the 2008 NIH criteria. Pre- and post-CEUS findings were reviewed. Tumor size, lobular border, heterogeneity, cystic areas, calcification and intratumoral gas on US, irregular vessels, heterogeneous enhancement, and non-enhancing areas on CEUS were compared among different risk groups of GISTs. The relationship between time-intensity curve parameters and risk stratification was also analyzed.Results: Larger lesion size, lobulation, and cystic areas were associated with higher risk (P<0.05); however, margin, heterogeneity, calcification or intratumoral gas on US did not show significant association with tumor risk (P>0.05). Visualization of intratumoral irregular vessels and non-enhancing areas on CEUS were significantly correlated with higher risk classification (P<0.001), but heterogeneous enhancement was not. Quantitative analysis of time-intensity curve by CEUS showed that higher enhanced intensity (EI) was correlated with higher tumor risk, whereas arrival time (AT), time to peak enhancement (TTP), and area under the curve (AUC) were not correlated with tumor risk.Conclusions: The combination of conventional US and CEUS provides valuable information for preoperative risk stratification of GISTs.