Enhancement characteristics of liver focal nodular hyperplasia (less than 3 cm) by contrast-enhanced ultrasound

Objective To analyze the typical contrast-enhanced ultrasound (CEUS) enhancement characteristics of hepatic focal nodular hyperplasia (FNH) within 3 cm, and to discuss the diagnostic value of CEUS in small FNH lesions. Methods Forty-eight cases of FNH were retrospectively studied. All lesions were confirmed histopathologically after surgical resection. CEUS examinations with SonoVue were performed to characterize the enhancement patterns of lesions in 5 minutes. The whole wash in and wash out enhancement procedure of lesions were recorded and analyzed. Results All FNH lesions displayed a rapid hyper-enhancement in arterial phase by CEUS, 39 lesions of which showed spring-like enhancement; 8 lesions showed spoke-like enhancement; 1 lesion showed dendritic enhancement. 6.3%(3/48) of the lesions showed central scar, and feeding arteries was found in 52.1%(25/48) lesions. According to echogenicity shift of the lesions in various phases, 20.8%(10/48) FNH showed "fast-in and slow-out" , 64.6%(31/48) showed "fast-in and synchronous-out" , and 14.6%(7/48) showed "fast-in and fast-out" . According to "fast-in and synchronous-out" or "fast-in and slow-out" by CEUS, the accuracy rate of benignity reached 85.4%(41/48). According to any of the spring-like enhancement, spoke-like enhancement, central scars or feeding arteries, the accuracy rate of diagnosis of FNH within 3 cm reached 97.9%(47/48), and 81.3%(39/48) of which were diagnosed through spring-like enhancement. Conclusions CEUS is helpful in diagnosis of FNH within 3 cm by showing various characteristic enhancement patterns, and spring-like enhancement is the most important sign in diagnosis of FNH less than 3 cm. CEUS has high diagnostic value for FNH less than 3 cm. Key words: Contrast-enhanced ultrasound; Liver focal nodular hyperplasia; Enhancement pattern