Abstract: Objective To investigate the application and diagnostic value of contrast-enhanced ultrasonography (CEUS) and color Doppler flow imaging (CDFI) for hepatic focal nodular hyperplasia (FNH).Methods Thirty-two patients with FNH admitted from May 2014 to June 2015 were enrolled to receive CEUS and CDFI, and their characteristics were retrospectively analyzed.Results Among the 32 cases, CEUS showed that lesions enhancements arose at 12-16 s and quickly homogeneously perfused in arterial phase, including 24 cases of central type with spoke-like enhancements, 8 of integral type with 5 eccentric and 3 mass-like enhancements. In portal phase, most cases manifested as high echo, while a few of cases showed equal or low echo, including 1 of visible hypoechoic central scar. In delayed phase, it showed high echo in 18 cases (18/36), equal echo in 10 cases (10/32) and low echo in 4 cases (4/32). CDFI revealed 37 positive lesions in these patients, including single lesion in 28 cases (28/32) and multiple lesions in 4 cases (4/32). Most hyperplastic nodules were uniformly distributed in the right hepatic lobe. The diameter of intrahepatic nodules was 3.4 cm in average, ranging from 2.5 to 5 cm. Intrahepatic nodules were hypoechoic in 4 cases (4/32), slightly hypoechoic in 3 (3/32), hyperechoic in 8 (8/32), slightly hyperechoic in 14(14/32) and isoechoic in 2 (2/32). The nodules were roundish in 26 cases (26/32) and irregular in 6 (6/32), with clear boundaries in 19 cases (19/32), obscure in 10 (10/32) and surrounding acoustic halo in 3 cases (3/32). Color Doppler ultrasound examination showed low-resistance artery flow spectrum in all lesions, with 22 cases of typical spoke-and-wheel blood flow signals.Conclusion CEUS and CDFI dynamically demonstrates the characteristics of blood perfusion in FNH lesions, which might play crucial roles in diagnosis and differential diagnosis of FNH.

Key words: Contrast-enhanced ultrasonography; Color Doppler flow imaging; Hepatic focal nodular hyperplasia