A study on the inconsistency of arterial phase hypervascularity detection between contrast-enhanced ultrasound using sonazoid and gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid magnetic resonance imaging of hepatocellular carcinoma lesions

Purpose By analyzing possible factors contributing to imaging misevaluation of arterial phase (AP) vascularity, we aimed to provide a more proper way to detect AP hypervascularity of hepatocellular carcinomas (HCCs) using the noninvasive imaging modalities magnetic resonance imaging (MRI) and contrast-enhanced ultrasound (CEUS). Methods We retrospectively recruited 164 pathologically confirmed HCC lesions from 128 patients. Using CEUS with Sonazoid (SCEUS) and gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid MRI (EOB-MRI), AP vascularity of the lesions was evaluated and inconsistencies in interpretation were examined. Indicators of margin, echogenicity, and halo and mosaic signs of lesions on grayscale US; depth of lesions on SCEUS; and tumoral homogeneity, signal contrast ratio of lesions to the surrounding area on precontrast and AP images on EOB-MRI, and histological grade were investigated. Results When precontrast images were used to adjust the AP enhancement ratio, the proportion of inconsistent interpretations of AP vascularity declined from 26.2% (43/164; 29 non-hypervascularity instances using EOB-MRI and 14 using SCEUS) to 16.5% (27/164; 7 using EOB-MRI and 20 using SCEUS). Greater lesion depth (P = 0.017), ill-defined tumoral margin (P = 0.028), absence of halo sign (P = 0.034), and histologically early HCC (P = 0.007) on SCEUS, and small size (P = 0.012) and heterogeneity (P = 0.013) of lesions and slight enhancement (low AP enhancement ratio) (P = 0.018 and 0.009 before and after adjustment) on EOB-MRI, may relate to undetectable hypervascularity. Conclusions SCEUS and EOB-MRI may show discrepancies in evaluating AP vascularity in the case of deep, ill-defined, heterogeneous, slightly enhanced lesions, and histologically early HCCs. We recommend adjusting AP with precontrast images in EOB-MRI, and combining both modalities to detect hypervascularity.