Background: Chronic liver disease is a worldwide problem with many causes, and there are varying degrees of fibrosis that can develop into cirrhosis. Many methods have been used to evaluate the grading of fibrosis, such as liver stiffness measurement by ultrasound-based transient elastography and the newly-developed shear wave elastography, including point shear wave and 2D shear wave elastography.
Objective: To compare the use of mean and median values in liver stiffness measurements made by two shear wave elastography modalities: point shear wave and 2D shear wave elastography.
Material and Method: This was a retrospective study of 90 patients with liver disease in Rajavithi Hospital between March 2016 and January 2017, evaluated by means of transient elastography, point shear wave elastography and 2D shear wave elastography. Correlations between the mean and the median values of each study were examined using transient elastography (TE) as the reference method.
Results: Ninety patients with liver disease were included, with mean age+SD of 49.49+12.75 years (range 24 to 97). The ratio of males to females was 2: 3. The correlation (r) values of mean and median of point shear wave elastography were 0.675 and 0.635 respectively, while for 2D shear wave elastography they were 0.854 and 0.844 respectively.
Conclusion: There was no significant difference between correlations arrived at using mean and median values for liver
stiffness measurement. The correlation between TE and 2D shear wave was more accurate than that of point shear wave elastography and TE.

Keywords: Liver stiffness, Shear wave elastography, Point shear wave elastography, 2D shear wave elastography, Mean, Median