The coefficient of determination is affected by the attenuation coefficient in attenuation imaging

Abstract

Aims: Attenuation imaging (ATI) is a new ultrasonography method of evaluating hepatic steatosis. Attenuation coefficients (ACs) in the region of interest are measured using two-dimensional ultrasonography. ATI also displays the coefficient of determination (R²) as an index of AC reliability. This study aimed to elucidate R² values in patients who underwent ATI in clinical practice and to determine factors that influence R² values.
Methods: This study included 749 patients who underwent ATI to evaluate hepatic steatosis at a single center. All abdominal ultrasound examinations were performed by one of the five experienced ultrasonographers. The AC and R² values were measured five times, and the median values were calculated. Multivariate analysis was conducted to identify factors affecting R² values.
Results: One hundred and nine (15%) patients showed R² values of < 0.80, of which 108 had non-fatty liver. Further, the R² value was strongly correlated with AC (correlation coefficient = 0.842). Uncomplicated diabetes (Odds ratio [OR], 2.68) and AC (< 0.60 dB/cm/MHz; OR, 72.76) were identified as independent factors associated with low R² values (< 0.80).
Conclusion: ATI in patients with non-fatty liver showed low R² values. Worldwide standardization of the ATI measurement method is urgently needed for consistent results.