Objective To evaluate the methodology of attenuation imaging (ATI) in liver examination.
Methods A total of 200 subjects were included and underwent the conventional ultrasound examination and ATI examination. The success rates of measuring position, the number of measurements, the inter- and intra-observer consistency were analyzed. Intraclass correlation coefficient (ICC) was used to analyze the intra-observer reproducibility and the consistency between the results of different measurements and the mean values of 10 measurements.
Results The success rates of the left and right lobes of the liver in healthy subjects were 64% and 100%, respectively, ICC of the intra-observer reproducibility in the right lobe of the liver was 0.948; the success rates of the left and right lobes of the liver in fatty liver subjects were 80% and 100%, respectively, ICC of the intra-observer reproducibility in the right lobe of the liver was 0.996. For the right lobe of the liver in healthy subjects, the ICC of 5 and 7 repeated measurements was 0.904 and 0.957, respectively, both showed no statistically significant differences as compared with 10 repeated measurements. For the right lobe of the liver in fatty liver subjects, the ICC of 2 and 5 repeated measurements was 0.975 and 0.994, respectively, both showed no statistically significant differences as compared with 10 repeated measurements. There was no statistically significant difference in measurement results between the 2 observers.
Conclusions The success rate of ATI for liver measurement is high and has good repeatability, and the best measuring position is the right lobe of the liver. For the detection of ATI in healthy subjects, 5 times should be the minimum number of measurements and 7 times should be the optimal number of measurements; and for the detection of ATI in patients with fatty liver, 2 times should be the minimum number of measurements and 5 times should be the optimal number of measurements.
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