Published online Dec 14, 2020. doi: 10.3748/wjg.v26.i46.7416
Peer-review started: September 18, 2020
First decision: October 17, 2020
Revised: October 30, 2020
Accepted: November 13, 2020
Article in press: November 13, 2020
Published online: December 14, 2020
Shear wave elastography (SWE), which could reflect tissue stiffness quantitatively, is the technologic leap of ultrasound (US) and is playing a more and more important role clinically. SWE is a convenient and cheap method with good repeatability and without any risk of radiation. The values of SWE in the differential diagnosis of thyroid and breast nodules and the assessment of liver fibrosis are significant. However, its value for the differential diagnosis between malignant and benign focal liver lesions (FLLs) was not widely accepted yet.
The World Federation for Ultrasound in Medicine and Biology guidelines 2018 did not recognize the value SWE for the differential diagnosis between malignant and benign FLLs. Previous studies about SWE application in liver usually used mean elasticity as the parameter. Considering the inhomogeneity of the stiffness of FLLs, maximal elasticity (Emax) might be the suitable parameter to reflect the stiffness of FLLs and to differentiate malignant FLLs from benign ones. So, it was necessary to explore the value of SWE with Emax in differential diagnosis of solid FLLs.
We aim to explore the value of SWE with Emax in differential diagnosis of FLLs.
This study included 104 solid FLLs and 50 healthy volunteers, who were examined using conventional US and SWE. Coefficient of variation (CV) of virtual touch tissue quantification (VTQ) values in each volunteer was calculated after 10 consecutive measurements for each liver. Each lesion was diagnosed as benign or malignant using conventional US by a radiologist with 16 years’ experience in US. The largest VTQ value was recorded as Emax after 10 consecutive measurements for each FLL. The cut-off point of Emax was calculated by a receiver operating characteristic curve. The diagnostic efficiencies of conventional US, Emax, and combined test was calculated and compared.
The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of conventional US were 80.4%, 81.3%, 83.3%, 78.0%, and 80.8%, respectively. CV of the VTQ values in each volunteer ranged from 4.5% to 14.6%. Emax of malignant FLLs (3.29 ± 0.88 m/s) was significantly higher than that of benign FLLs (1.30 ± 0.46 m/s, P < 0.01) and that of livers in healthy volunteers (1.15 ± 0.17 m/s, P < 0.01). The cut-off point of Emax was 1.945, and the area under the curve was 0.978. The sensitivity and specificity of Emax were 92.9% and 91.7%, higher (but not significantly) than those of conventional US. Combined diagnosis of conventional US and Emax using parallel testing improved the sensitivity to 100% with specificity of 75%.
SWE is a convenient and easy method that can provide accurate stiffness information of solid FLLs. Emax is useful for the differential diagnosis of malignant and benign FLLs, and combined with conventional US, the diagnostic efficiency is improved.
In this study, we demonstrated the value of SWE with Emax in differential diagnosis of FLLs. Prospective study with large numbers of patients and different kinds of FLLs will be needed to confirm the results. The application of two-dimensional SWE may be more convenient and accurate for differentiating FLLs.