Diagnostic Performance of Greyscale Ultrasound in Detecting Fatty Liver Disease in a Type 2 Diabetes Population Using FibroScan as the Reference Standard

Introduction Brightness mode ultrasound (B-mode US) and FibroScan (Echosens, Paris, France) are the two ultrasound methods often recommended for screening non-alcoholic fatty liver disease (NAFLD) in persons with type 2 diabetes mellitus (T2DM). This study assessed the diagnostic performance of B-mode US using FibroScan as the reference standard. Methods Persons with a known history of T2DM were invited to screen for NAFLD using B-mode US and FibroScan on separate days within a one-month period. Assessors of B-mode US and FibroScan were blinded to each other’s findings. Both B-mode US and FibroScan independently assessed and graded each participant for the presence of NAFLD. Using the diagnostic test findings of FibroScan as a reference standard, the sensitivity and specificity of B-mode US were analyzed. The area under the receiver operating characteristic curve (AUROC) was analyzed using Jamovi (version 2.3.21). A multinomial logistic regression of the B-mode US and FibroScan in predicting NAFLD grade was also analyzed. Results A total of 171 participants were assessed. B-mode US detected NAFLD in T2DM patients with 63.6% sensitivity, 65.6% specificity, and 0.646 AUROC. Sensitivity and specificity in overweight and obese participants were 36-43% and 76-85%, respectively. Multinomial logistic regression demonstrated an insignificant statistical relationship between FibroScan and B-mode US in predicting grade 1 steatosis (p-value = 0.397), which was significantly affected by a higher BMI (p-value = 0.034) rather than a higher liver fibrosis level (p-value = 0.941). The logistic regression further showed a significant relationship between B-mode US and FibroScan in predicting steatosis grade 2 (p-value = 0.045) and grade 3 (p-value < 0.001), which was not significantly affected by BMI (p-value = 0.091). Conclusion B-mode US can replace FibroScan for severe steatosis; however, it cannot be used to screen for NAFLD in T2DM patients due to lower sensitivity for early detection in the overweight.