Comparison of Computed Tomography Densitometry and Shear Wave Elastography Velocity Measurements for Evaluation of the Liver Volume in the Nonalcoholic Fatty Liver Disease

Abstract

Purpose: The aim of the present study is to evaluate and compare the values of velocities measured by the shear wave elastography (SWE), and those of the liver attenuation index (LAI) determined by the computerized tomography (CT) densitometry, in the nonalcoholic fatty liver disease (NAFLD). In other words, we aimed to compare the values of density measured by CT and the stiffness determined by elastography, in the liver steatosis. In addition, it is to investigate the effect of NAFLD on the liver volume. Materials and methods: Forty five cases with hepatosteatosis who had undergone abdominal CT and 50 individuals who did not exist with fatty liver clinically and radiologically, were investigated by ultrasonography (US) and SWE. The liver and spleen attenuation values were then measured in the images of non-contrast CT, and the LAI indices were calculated. Contrast images of abdomen were processed by the CT-Volume software and measurements of liver volume were performed using the interactive and automatic liver segmentation techniques together. Values of the liver volume, LAI, liver dimensions, and the shear wave velocities were determined and recorded in the patients with hepatosteatosis and controls; statistical comparisons were performed then. Results: In the nonalcoholic fatty liver, the mean value of velocity measured by SWE was found to be 1.08 (+/- 0.11) m/s, and that of LAI measured by CT densitometry was 13.68 (+/- 10.6). No correlation was observed between these two parameters (P>0.05). A high statistically significant difference between the patient and control groups in terms of the liver volume, LAI values and liver size has been observed (P<0.01). Direct correlations existed between the liver volume and LAI values, and the grades in US, and highly significant differences were determined (P<0.01). The mean values of the liver volume in the patient and control groups were determined to be 1917.4 (+/- 425.9) cm(3) and 1311.4 (+/- 241.4) cm(3), respectively. A high statistically significant difference between the groups in terms of liver volumes has been observed (P<0.01). Conclusion: In our study, we determined no correlation between the values of velocity measured by SWE, and the values of LAI measured by CT densitometry, in the NAFLD (P>0.05). This result indicates that there is no relation between the degree of stiffness evaluated by SWE, and the attenuation values measured by CT densitometry, in the non-alcoholic fatty liver. The liver volume was found to increase in NAFLD. We concluded that the CT densitometry can be used as an auxiliary technique associated with the US, in determining the degree of steatosis in NAFLD.