Usefulness of Acoustic Radiation Force Impulse Imaging in the Differential Diagnosis of Benign and Malignant Liver Lesions

Abstract

Acoustic radiation force impulse imaging (ARFI) is a newly developed technique for the evaluation of tissue stiffness. It has been applied to evaluate liver fibrosis, but only limited data for liver lesions are available. The aim of this study was to evaluate the tissue stiffness of liver lesions by using ARFI to differentiate benign from malignant liver lesions. ARFI was performed in 116 consecutive patients who had 128 liver lesions (60 benign, 68 malignant). The elastographic images of virtual touch tissue imaging (VTI) and the values of virtual touch tissue quantification (VTQ) were obtained and analyzed. The area under the curve and cutoff value for VTQ value, both of which were obtained by using a receiver operating characteristic curve analysis, were used to assess diagnostic performance. On the elastographic images of VTI, 57 (83.8%) malignant liver lesions and 33 (55.0%) benign liver lesions appeared stiffer compared with the surrounding liver parenchyma. There were statistical differences between malignant and benign liver lesions (P<.05). The VTQ median value of malignant and benign liver lesions were 3.14 m/sec (average value 3.16 ± 0.80 m/sec, range 1.17‒4.45 m/sec) and 1.35 m/sec (average value 1.47 ± 0.53 m/sec, range 0.74‒3.26 m/sec), respectively (P < .001). With a cutoff value of 2.22 m/sec for VTQ value, the sensitivity, specificity, and accuracy for malignancy were 89.7%, 95.0%, and 92.2%, respectively. ARFI can provide the elastographic images and elastographic values of liver lesions by VTI and VTQ, which is helpful in the differentiation between benign and malignant liver lesions and might become the imaging modality of the future.