Sonazoid Contrast-Enhanced Ultrasound Hypoenhancement Characteristics and Influencing Factors of Hepatic Hemangiomas:...

Given the high hypoenhancement prevalence of hepatic hemangiomas (HHs) during the transitional phase and Kupffer phase (KP) of Sonazoid contrast-enhanced ultrasound (CEUS), this study aimed to investigate the hypoenhancement phenomenon pattern and its influencing factors.

This was a prospective multicenter study. A total of 136 patients with HHs were enrolled from 26 medical centers, including 76 cases in the KP hypoenhancement group and 60 cases in the KP non-hypoenhancement group. Enhancement characteristics and patterns at different time points during the transitional phase were analyzed between the two groups. Statistical analyses included Mann-Whitney U test for two independent samples, chi-square test or Fisher's exact test for categorical variables and Spearman's rank correlation analysis for the relationship between hypoenhancement prevalence and time points. Survival analysis was used to compare differences in the start time of hypoenhancement among HHs with different characteristics. Multivariate Cox regression analysis was performed to identify the influencing factors of KP hypoenhancement.

The hypoenhancement prevalence of HHs in the KP was 55.9% (76/136). The proportions of hyperenhancement, isohyperenhancement, mild hypoenhancement and marked hypoenhancement were 5.9% (8/136), 38.2% (52/136), 41.9% (57/136) and 14.0% (19/136), respectively. There was a significant positive correlation between the hypoenhancement prevalence and time points (r_s = 0.993, p < 0.001). The main start time of hypoenhancement was 4 min (p < 0.001). The median hypoenhancement time in the KP hypoenhancement group was 5.5 min. Two-dimensional ultrasound (2-D-US) echo type and maximum diameter were independent influencing factors for Sonazoid KP hypoenhancement: hypoechoic lesions were more likely to present hypoenhancement compared with hyperechoic ones (HR = 1.80, 95% CI: 1.10-2.95, p = 0.020); both lesions ≥5 cm and those between 2 and 5 cm had a higher likelihood of hypoenhancement compared with lesions <2 cm, with HR = 2.58 (95% CI: 1.18-5.65, p = 0.018) and HR = 2.32 (95% CI: 1.35-3.97, p = 0.002), respectively.

More than half of HHs show hypoenhancement in the KP of Sonazoid CEUS, and mild hypoenhancement is the main enhancement pattern among hypoenhancement cases. Hypoenhancement mostly occurs after 4 min, and the hypoenhancement prevalence gradually increases over time. The independent influencing factor for KP hypoenhancement is 2-D-US hypoechogenicity and maximum diameter greater than 2 cm.