Is Shear Wave Elastography Effective for Characterization of Hepatic Focal Lesions?

Abstract Background: Shear wave elastography (SWE) is initially developed to investigate hepatic stiffness and measures soft tissue changes that is altered by specific pathological processes. Nowadays there is great need for a noninvasive method to differentiate benign & malignant hepatic focal lesions (FLLs) without dependency on invasive method as biopsy that cause pain bleeding & even death. Aim of Study: Was to detect the diagnostic accuracy of shear wave elastography in the characterization of hepatic focal lesions. Patients and Methods: This study included 138 patients presenting with hepatic focal lesion detected by abdominal ultrasound examination. The following data was recorded: The built-in ROI of the system ranging from dark blue indi-cating the lowest stiffness, to dark red indicating the highest stiffness. The stiffness of adjacent liver parenchyma was also measured to obtain a direct reference for the SWE measure-ments of the lesion. For each focal lesion and adjacent liver parenchyma, five measurements were performed. Median kPa was chosen as the representative value for both the lesion and the parenchyma. Results: SWE acquisitions for the 138 patients (84 males 61% and 54 females 39% with age range between 25-85 years old were successfully evaluated,The sensitivity of 100% and a specificity of 80% at a cut-off value of 11.13 kPa. The positive predictive value of about (94.7%) and negative predictive value of about (100%) with total accuracy of about (95.7%). There is significant difference in stiffness between benign and malignant lesions with (p<0.001), The mean (±SD) stiffness value of malignant lesions was (22.53±9.33 kPa), and that of benign lesions was (9.36±2.48 kPa). The mean (±SD) stiffness of malignant lesions was significantly higher compared with that of benign lesions (p<0.0001). The mean (±SD) lesion to parenchyma ratio of malignant lesions was (2.53±1.31) with no significant difference from that of benign FLLs (1.86±0.62) as p-value is higher than 0.05 (p=0.174). The mean (±SD) of Hepatocellular carcinoma was the lowest in comparison to other sub-types of malignant lesions. Lym-phoma showed the highest stiffness value. The mean (±SD) lesion to parenchymal stiffness of Hepatocellular carcinoma was (1.86±0.68) KPa, with no significant difference from that of benign focal lesions (1.86±0.62) as p-value is higher than 0.05 (p=0.280). Conclusion: SWE provides information on hepatic FLLs and would help discriminate malignant from benign masses, especially for patients unsuitable for contrast-enhanced imag-ing. SWE can characterize hepatic focal lesions successfully based on the tissue elasticity values.