Discrimination between neoplastic and non-neoplastic lesions in cirrhotic liver using contrast-enhanced ultrasound

Objectives: To assess the value of contrast-enhanced ultrasound (CEUS) in differentiating hepatocellular carcinoma (HCC) from non-neoplastic lesion in cirrhotic liver in comparison with baseline ultrasound. Methods: A total of 147 nodules (diameter <= 5.0 cm) in 133 cirrhotic patients (mean age +/- standard deviation: 52 +/- 13 years, range 20-82 years; gender: 111 males and 22 females) were examined with CEUS. There were 116 HCCs, 26 macroregenerative nodules and 5 high-grade dysplastic nodules. CEUS was performed with a real-time contrast-specific mode and a sulphur hexafluoride-filled microbubble contrast agent. Results: Hypervascularity was observed in 94.8% (110/116) HCCs, 3.8% (1/26) macroregenerative nodules and 60.0% (3/5) high-grade dysplastic nodules during arterial phase on CEUS. Detection rates of typical vascular pattern (i.e. hypervascularity during arterial phase and subsequent washout) in HCCs with a diameter of <= 2.0 cm, 2.1-3.0 cm and 3.1-5.0 cm were 69.2% (27/39), 97.1% (33/34) and 100.0% (43/43), respectively. CEUS significantly improved the sensitivity [88.8% (103/116) vs 37.1% (43/116), p<0.001], negative predictive value [70.5% (31/44) vs 31.5% (29/92), p<0.001], and accuracy [91.2% (134/147) vs 49.0% (72/147), p<0.001] in differentiating HCCs from non-neoplastic lesions when compared with baseline ultrasound. However, the sensitivity and accuracy of CEUS for HCCs <= 2.0 cm in diameter were significantly lower than those for HCCs of 2.1-3.0 cm and 3.1-5.0 cm in diameter. Conclusions: CEUS improves diagnostic performance in differentiating HCCs from non-neoplastic nodules in cirrhotic patients compared with baseline ultrasound. Diagnosis of HCCs <= 2.0 cm diameter by CEUS is still a clinical concern, and thus needs further investigation.