| ObjectiveTo investigate the methodology of Acoustic Radiation Force Impulse (ARFI) technology in the measurement of liver Shear Wave Velocity (SWV) and to evaluate the SWV in the assessment of the liver fibrosis.MethodsThe study subjects were composed with 15 normal controls and 141 patients with liver diseases. The measurements of liver SWV, while the participants were in supine position and lateral position, were performed by two operators using a ultrasonic instrument named ACUSON S2000. The correlations between SWV and each parameters such as patients'gender, age, serum markers and pathological grades of the liver were analyzed. And the cutoff values of SWV for diagnosis of S≥1, S≥2, S≥3, S = 4 were determined using Receiver Operating Characteristic curve, respectively.Results1,The consistency of liver SWV's measurements were significant both in inter-operators and in different positions of participants. The Liver SWV measured by two operators was statistic significantly different, and theirs'areas under receiver operating characteristic curves (AUROC) of liver SWV between different operators were pretty much the same, and all the AUROCs were over 0.8 (differ from 0.002 to 0.019). The correlation coefficient between the SWV values and fibrosis grades was higher when subjects were in lateral position than in spine position. In order to include multiple (four) measured values, we took the average of all SWV measurements to correlate with fibrosis stage, the correlation coefficient was higher than the other four groups.2,The significant positive correlations were found between the SWV values and the parameters such as age, ALT,globulin,total bilirubin, fibrosis grade and steatosis grade, respectively (p<0.05), and the maximum correlation coefficient was found between the SWV values and the fibrosis grade in our study(β=0.615).3,This results showed that except for the SWV values between the S0 and S1, S2 and S3 stages of liver fibrosis , the SWV values between other two groups (S4 and S1, S2, S3,respectively; S3, and S0, S1, respectively; S2, and S0, S1 ,respectively) were significantly different (p <0.01). Using the cutoff values of 1.32m/s, 1.53m/s, 1.79m/s and 2.03m/s for diagnosis of S≥1, S≥2, S≥3and S = 4, the corresponding AUROCs were 0.826, 0.829, 0.845 and 0.880, respectively.Conclusions1,The measurement of SWV is repeatable, the values are not affected by subjects'position. However, due to the uneven distribution of liver fibrosis, the values may differ measured by different operators, while the difference will not affect the accuracy for diagnosis of fibrosis. To elevate the correlation between the liver SWV and fibrosis grades , we proposed that the ROI frame should be placed in the right lope of liver, beyond 2cm far from liver capsule, at the same time, measurements should performed in multiple spot and much frequency.2,Fibrosis grade is the major factor of liver SWV, the liver SWV increase with the increasing of fibrosis grades. Hepatic steatosis grade is also an independent factor for liver SWV, in addition, patients in the stage of inflammation (with the elevation of ALT, globulin and total bilirubin ) can also increase the liver SWV. Therefore, we should combine these serum marker into consideration to evaluate the fibrosis grade.3,Shear Wave Velocity measurement can directly reflect the elasticity modulus of liver; and the values were positive correlate with fibrosis grade. The operation is easy, time-saving and repeatable. It is a non-invasive method to evaluate the liver fibrosis. For further expansion of studies cases, Shear Wave Velocity measurement can be an alternative non-invasive method to evaluate the liver fibrosis.
|
PDF Full Text Request