Contrast vector imaging for differential diagnosis of focal liver lesions: Analysis of tumoral vascular structures and flow characteristics.

PURPOSE

To assess the efficacy of contrast vector imaging (CVI) in detecting tumoral vascular structures and flow characteristics of focal liver lesions (FLLs) for differential diagnosis.

MATERIALS AND METHODS

In this prospective study, 65 participants with FLLs underwent CEUS using SonoVue with high-frame-rate imaging technique between July 2019 and October 2020. CVI was obtained by post-processing arterial cine imaging of CEUS. Tumoral vascular structures, velocity histogram, and mean velocities were compared among hepatocellular carcinoma (HCC), non-HCC malignancies, and benign tumors using the Chi-square and Kruskal-Wallis tests, respectively. The areas under the receiver operating characteristic curve (AUC) of CEUS in determining HCC probability was compared to that of CEUS with CVI using a z-test.

RESULTS

CVI was technically successful in 52 of 65 (80%) participants (19 HCCs, 13 non-HCC malignancies, and 20 benign tumors). The detectability of tumoral vascular structures was significantly higher in CEUS with CVI, compared to CEUS alone (46.2% [24/52] vs. 100.0% [52/52], p<0.001). On CEUS with CVI, complex intratumoral and peripheral vessels were frequent in HCCs (100% of HCCs, 46.2% of non-HCC malignancies, and 70.0% of benign tumors), while detour vessels were frequent in non-HCC malignancies (none of HCCs, 53.8% of non-HCC malignancies, and 10.0% of benign tumors) (p<0.001). The mean velocity of HCC (26.3 mm/s) was the highest, while that of non-HCC malignancy (20.6 mm/s) was the lowest (p<0.001). CEUS with CVI showed higher AUC, compared to CEUS in both reviewers (0.851 vs. 0.963, p = 0.005 for reviewer 1; 0.853 vs. 0.982, p = 0.023 for reviewer 2).

CONCLUSION

CEUS with CVI better visualized vascular structures and flow characteristics of FLLs, and showed better diagnostic performance in determining HCC probability than CEUS.