OBJECTIVETo investigate the clinical value of acoustic radiation force impulse (ARFI) elastography in the differential diagnosis of focal liver lesions.

METHODSARFI elastography was performed for 169 lesions from 163 patients with focal liver lesions and 15 healthy volunteers, and the virtual touch tissue imaging (VTI) findings and measured value of shear wave velocity (SWV) of liver lesions were obtained and compared between groups. The t-test was applied for comparison of means between two groups; the one-way analysis of variance was applied for comparison of means between multiple groups, and the Student-Newman-Keuls test was applied for further comparison between any two groups.

RESULTSBenign focal liver lesions were stiffer or softer than or had the same stiffness as the surrounding liver parenchyma. These lesions had a uniform texture, and the ratio between their diameters on elastographic images and two-dimensional images was close to 1. The typical VTI finding of hemangioma lesions was"honeycomb"pattern. Most malignant focal liver lesions were stiffer than the surrounding liver parenchyma, and the ratio between their diameters on elastographic images and two-dimensional images was greater than 1. The typical VTI finding of metastatic lesions was"bull's eye"sign. With a measured SWV of 2.08 m/s as the diagnostic threshold for malignant liver lesions, its sensitivity, specificity, and accuracy were 90.3%, 76.9%, and 84.2%, respectively. Poorly differentiated hepatocellular carcinoma (HCC) showed a significant increase in stiffness compared with moderately differentiated HCC (t = 5.319, P = 0.025) and well-differentiated HCC (t = 6.372, P = 0.011).

CONCLUSIONARFI elastography can reflect changes in the stiffness of focal liver lesions accurately, and is useful for the differential diagnosis of benign and malignant focal liver lesions.