Usefulness Of Acoustic Radiation Force Impulse Imaging In The Differential Diagnosis Of Benign And Malignant Liver Lesions

Background 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 is available.Objective The aim of this study was to evaluate the tissue stiffness of liver lesions by using ARFI to differentiate benign from malignant liver lesions.Methods ARFI were performed in 116 consecutive patients who had 128 liver lesions(60 benign,68 malignant).The elasticity images of virtual touch tissue imaging(VTI) and the values of virtual touch tissue quantication(VTQ) were obtained,the elasticity images of VTI and the values of VTQ were analyzed.The area under the curve and cut-off point, both of which were obtained by using a receiver operating characteristic curve analysis,were used to assess diagnostic performance.Final diagnosis was established by histopathology,CT,MRI.Results On the elasticity images of VTI, malignant liver lesions appeared stiffer for 57 (83.8%) lesions compared with the surrounding liver parenchyma.Benign liver lesions appeared stiffer for 33 (55.0%) lesions compared with the surrounding liver parenchyma.There were statistical differences between malignant and benign liver lesions(P<0.05). 49 (72.1%) malignant liver lesions and 4 (6.7%) benign liver lesions displayed a clearer margin by ARFI than by conventional ultrasonography(US).There were statistical differences between malignant and benign liver lesions(P<0.001). The range of 35 (51.5%) malignant liver lesions and 1 (1.7%) benign liver lesions was larger by ARFI than by conventional US, There were statistical differences between malignant and benign liver lesions (P<0.001).The VTQ median value of malignant liver lesions and benign liver lesions were 3.14 m/s(mean 3.16±0.80 m/s,range 1.17～4.45 m/s) and 1.35 m/s (mean 1.47±0.53 m/s, range 0.74～3.26 m/s), respectively(P<0.001).With a cut-off value of 2.22 m/s for VTQ value,the sensitivity,specificity,and accuracy for malignancy were 89.7%,95.0% and 92.2%,respectively.Conclusions ARFI can provide the elasticity images and elasticity values of liver lesions by VTI and VTQ,It is helpful in the differentiation between benign and malignant liver lesions and might become the imaging modality of the future.