Background: The purpose of this study was to determine the enhancement patterns of focal liver lesions on triphasic CT and to evaluate the role of Acoustic Radiation Force Impulse (ARFI) elastography in the differentiation of benign from malignant liver lesions.
Methods: A total of 38 patients (15 male, 23 female with mean age of 49.4 years) with focal liver lesions underwent triphasic CT and the enhancement patterns of the lesions were recorded. The patients were also evaluated with ARFI elastography using Virtual Touch Tissue quantification (VTQ) technique and shear wave velocity (SWV) values were obtained for quantification of their stiffness. The area under the curve and cut-off value for SWV were obtained using a receiver operating characteristic curve analysis. The findings were correlated with fine needle aspiration cytology or histopathology results.
Results: Triphasic CT correctly diagnosed 96.2% of the malignant lesions (n=26) and 100% of the benign lesions (n=12). On ARFI elastography, there was a significant difference (p< 0.0001) between the SWV of the benign (mean ± SD = 1.775 ± 0.488 m/s) and malignant (mean ± SD = 3.271 ± 0.561 m/s) liver lesions. With a cut-off value of 2.44 m/s for shear wave velocity, the sensitivity, specificity, and area under the receiver operating characteristic curve for malignancy were 92.3 %, 91.7%, and 0.968 respectively.
Conclusions: ARFI elastography is a promising technique that can non-invasively provide information regarding the tissue stiffness which along with triphasic CT is helpful in differentiating benign and malignant focal liver lesions.