Non-Invasive Prediction of Microvessel Density in Pediatric Hepatoblastoma Using Contrast-Enhanced Ultrasound Quantitative Parameters

<b>Background</b>: The purpose of this study was to examine the relationship between qualitative characteristics and quantitative parameters from contrast-enhanced ultrasound (CEUS) and microvessel density (MVD) in hepatoblastoma (HB), as well as to investigate whether CEUS could be utilized as a non-invasive method for predicting HB progression. <b>Methods</b>: This retrospective analysis was carried out in one medical center and included 34 children with histopathologically confirmed HB. Both grayscale ultrasound and CEUS results were reviewed. Lesions were evaluated using time-intensity curve (TIC) analysis software to extract quantitative parameters. Postoperative tissue specimens were stained with CD34 immunohistochemistry, and MVD was quantified as the reference standard. Statistical analyses were conducted to assess the correlation between CEUS findings and MVD. <b>Results:</b> Lesions were separated into high (<i>n</i> = 21, 61.76%; MVD ≥ 41) and low (<i>n</i> = 13, 38.24%; MVD < 41) MVD groups, using the median microvessel density of 41 vessels per high-power field (HPF) as the cutoff. High MVD lesions exhibited a significantly higher incidence of penetrating vessels compared with low MVD lesions (<i>p</i> < 0.05). Elevated MVD levels were significantly associated with increased Adler-grade blood flow (<i>p</i> < 0.05). Both TIC-derived and relative quantitative parameters exhibited significant intergroup differences. Among the relative parameters, the relative wash-out rate (rWoR) was significantly higher in the low MVD group (<i>p</i> < 0.05). Moreover, the Receiver Operating Characteristic (ROC) curve analysis indicated that an rWoR threshold of ≥1.36 could serve as a predictor for low MVD, resulting in 76.9% sensitivity and 81.0% specificity (AUC = 0.802; 95% CI: 0.634-0.970; <i>p</i> = 0.003). <b>Conclusions</b>: CEUS revealed an association with MVD, supporting its potential as a non-invasive tool to characterize tumor vascularity.