Impact of Hepatocellular Carcinoma Tumor Size on Sonazoid Contrast-Enhanced Ultrasound Enhancement Features

Objective: The aim of the work described here was to evaluate the impact of hepatocellular carcinoma (HCC) tumor size on Sonazoid contrast-enhanced ultrasound (CEUS) enhancement features, especially in tumors with diameters <= 30 mm and <10 mm.Methods: In this retrospective study, we included patients with histopathologically confirmed HCC lesions and divided them into three groups on the basis of tumor size. All patients underwent Sonazoid-enhanced CEUS examinations before surgery. B-mode ultrasound (BMUS) features and CEUS enhancement patterns were evaluated according to current World Federation for Ultrasound in Medicine and Biology Guidelines criteria. The chi(2)- and Student t-tests were used to compare differences between groups.Results: We included 132 patients with histopathologically confirmed HCC lesions from November 2020 to September 2022. On the basis of tumor size, patients were divided into group 1 (<10 mm, n = 5), group 2 (10-30 mm, n = 54) and group 3 (>30 mm, n = 73). On BMUS, most HCCs appeared heterogeneous but predominantly hypo-echoic (61.4%, 81/132) with ill-defined margins and irregular shapes. Meanwhile, iso-echoic features were more common in small HCCs <= 30 mm (15.3%, 9/59), but a mixed hyper- and hypo-echoic appearance was more common in HCCs >30 mm (17.8%, 13/73) (p = 0.003). On Sonazoid-enhanced CEUS, all HCCs presented arterial phase hyperenhancement (APHE) (100.0%, 132/132). Most HCCs >30 mm exhibited heterogeneous hyperenhancement (86.3%, 63/73), whereas nearly one-third of small HCCs <= 30 mm exhibited homogeneous hyperenhancement (35.6%, 21/59) (p = 0.003). In the portal venous phase, there was a significantly higher proportion of washout in HCCs >30 mm (84.9%, 62/73) than in small HCCs <= 30 mm (64.4%, 38/59) (p = 0.006). During the Kupffer phase, 11 additional hypo-enhanced lesions (mean size: 14.1 +/- 4.1 mm, iso-echoic on BMUS), which were also suspected to be HCC lesions, were detected in 5 patients with small HCCs <= 30 mm and 4 patients with HCCs >30 mm. All 5 cases of HCCs <10 mm exhibited APHE and late washout (>60 s). The majority (3/5, 60%) exhibited washout in the portal venous phase (70, 74 and 75 s), one case did so in the late phase (125 s) and another in the Kupffer phase (420 s).Conclusion: Tumor size had a significant impact on the washout features of HCC lesions on Sonazoid-enhanced CEUS. Small HCC lesions <= 30 mm had a higher proportion of relatively late washout in comparison to larger lesions. Sonazoid-enhanced CEUS might be helpful in the detection and characterization of HCC lesions <10 mm.

Automated summary

The impact of hepatocellular carcinoma (HCC) tumor size on Sonazoid contrast-enhanced ultrasound (CEUS) enhancement features was evaluated. The study found that tumor size had a significant impact on the washout features of HCC lesions, with smaller lesions exhibiting a later occurrence of washout.