Novel Ultrasound Liver Attenuation Imaging for Detection of Liver Steatosis: Comparison with MRI Based Imaging Methods with Liver Biopsy as A Reference Standard

PURPOSE: To evaluate the performance of the novel ultrasound attenuation imaging (ATI) with MRI-proton density fat fraction (PDFF) and proton magnetic resonance spectroscopy (proton-MRS) in detecting and grading of liver steatosis, using liver biopsy as a reference standard.
METHODS: From March 2019 to September 2021, 15 adult subjects (age: 38 years, Male/female:5/10 females, BMI: 38.5kg/m2) with morbid obesity planned for laparoscopic sleeve gastrectomy were recruited, and an intraoperative liver biopsy was performed. A control group of 8 healthy lean subjects (age: 25 years, Male/female: 4/4 females, BMI: 20.2kg/m2) was also enrolled. ATI, MRI-PDFF, and proton-MRS were performed on the same day and within two weeks before surgery.
RESULTS: Liver steatosis was present in 100% of the patients. ATI correlated with steatosis grade (r=0.833, p<0.001). MRI-PDFF correlated with steatosis grade (r=0.926, p< 0.001) and non-alcoholic steatohepatitis activity score (r=0.820, p=0.001). ATI correlated with MRI-PDFF (r=0.885, p<0.001) and proton-MRS (r=0.836, p<0.001), whereas proton-MRS correlated with MRI-PDFF (r=0.970, p<0.001). AUROCs of ATI were 0.91, 0.97, and 0.93 for detecting steatosis grades 1,2, and 3 respectively. The ATI cut-off points for detecting steatosis grades 1, 2, and 3 were 0.59, 0.60 and 0.63dB/cm/MHz, respectively. There were no significant differences of AUROCs of the imaging methods for the detection of steatosis grades 1 and 2 (All p>0.05).
CONCLUSIONS: ATI showed no significant difference in the diagnostic performance when compared to MRI-PDFF and proton-MRS.