Parametric imaging with contrast-enhanced ultrasound: Usefulness for characterization of dynamic effects of microvascularization for hepatocellular carcinoma and focal nodular hyperplasia.

OBJECTIVE: To evaluate whether parametric imaging with contrast-enhanced ultrasound (CEUS) is equal to experienced radiologists after review of CEUS in differentiating hepatocellular carcinoma (HCC) from focal nodular hyperplasia (FNH). METHODS: An image processing software was used to quantitatively analyze the CEUS clips of 30 HCCs (mean diameter, 3.4 ± 0.9 cm; range, 1.8-5.0 cm) and 30 FNHs (mean diameter, 3.0 ± 1.1 cm; range, 1.1-5.0 cm). Low mechanical index contrast specific imaging modes and contrast agent of SonoVue® were applied for CEUS. Fourteen HCCs were pathologically diagnosed and 16 were clinically diagnosed, whereas all the FNHs were confirmed by pathological examination. Quantitative parameters of HCC and FNH were compared. The diagnostic performance between parametric imaging and two experienced readers was compared using the receiver operating characteristic (ROC) curve analysis. RESULTS: On parametric imaging, the rise time, time to peak and mean transit time for HCC and FNH were 16.7 ± 11.1 s vs. 21.9 ± 9.0 s (P = 0.052), 29.9 ± 14.1 s vs. 33.2 ± 11.1 s (P = 0.322), 115.0 ± 90.9 s vs. 271.5 ± 147.6 s (P < 0.001), respectively. The ROC analysis showed that, for the differentiation between HCC and FNH, the cut-off point for mTT was 107.93 s with the Az value of 0.817 (95% CI: 0.703-0.931), and the Az value was 0.834 (95%CI: 0.728-0.941) for two experienced readers (P = 0.417 compared with mTT). The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were 96.7%, 66.7%, 81.7%, 74.4%, and 95.2%, respectively, for parametric imaging, and 86.7%, 76.7%, 81.7%, 78.8%, and 85.2%, respectively, for two experienced readers (all P > 0.05 compared with parametric imaging). CONCLUSION: Parametric imaging with CEUS is helpful for characterization the typical dynamic effects of microvascularization of HCC and FHH and is equal to experienced readers in the differential diagnosis between HCC and FNH. [ABSTRACT FROM AUTHOR]