A Comparative Study of Ultrasound Attenuation Imaging, Controlled Attenuation Parameters, and Magnetic Resonance Spectroscopy for the Detection of Hepatic Steatosis.

OBJECTIVES: To investigate the methodology and clinical application of ultrasound attenuation imaging (ATI) and comparative analyze the diagnostic performance of ATI and controlled attenuation parameters (CAP) for detecting and grading hepatic steatosis. METHODS: A total of 159 patients with NAFLD were prospectively enrolled. CAP and ATI examinations were performed within a week before proton magnetic resonance spectroscopy (1 H-MRS). Ten liver attenuation coefficient (AC) measurements by ATI were obtained in each patient. The interclass correlation coefficients (ICCs) of the intraobserver consistencies and the ICCs between the median of the first two through the first nine measurements and all 10 measurements were calculated. The correlations between 1 H-MRS, CAP, biological data, and ATI were evaluated. The significant factors associated with ATI and the diagnostic performance of ATI and CAP for detecting hepatic steatosis was evaluated. RESULTS: The median value of AC for detecting hepatic steatosis was 0.831 dB/cm/MHz. For the intraobserver consistency of ATI, the ICC was 0.931. Compared with 10 measurements, a minimum of four ATI measurements was required. The correlation of AC with hepatic fat fraction (HFF) was significantly higher than that of CAP (0.603 vs 0.326, P = .0015). The HFF and triglyceride (TG) were the significant factors for the ATI. The area under the receiver operating characteristics (ROC) curves of ATI and CAP were 0.939 and 0.788 for detecting ≥10% hepatic steatosis; 0.751 and 0.572 for detecting >33% hepatic steatosis. The cutoff values of ATI and CAP were 0.697 dB/cm/MHz and 310 dB/m for detecting ≥10% hepatic steatosis; 0.793 dB/cm/MHz and 328 dB/m for detecting >33% hepatic steatosis. The sensitivity of ATI and CAP were 85.92% and 52.11% for detecting ≥10% hepatic steatosis; 87.50% and 82.14% for detecting >33% hepatic steatosis. The specificity of ATI and CAP were 94.12% and 100% for detecting ≥10% hepatic steatosis; 54.37% and 43.69% for detecting >33% hepatic steatosis. CONCLUSIONS: ATI technology showed excellent intraobserver consistency and the optimal minimum number of ATI measurements was 4. ATI is a promising noninvasive, quantitative and convenient tool for assessing hepatic steatosis.