A Pilot Comparative Study of Quantitative Ultrasound, Conventional Ultrasound, and MRI for Predicting Histology-Determined Steatosis Grade in Adult Nonalcoholic Fatty Liver Disease

Abstract

OBJECTIVE The purpose of this study is to explore the diagnostic performance of two investigational quantitative ultrasound (QUS) parameters, attenuation coefficient and backscatter coefficient, in comparison with conventional ultrasound (CUS) and MRI-estimated proton density fat fraction (PDFF) for predicting histology-confirmed steatosis grade in adults with nonalcoholic fatty liver disease (NAFLD). SUBJECTS AND METHODS In this prospectively designed pilot study, 61 adults with histology-confirmed NAFLD were enrolled from September 2012 to February 2014. Subjects underwent QUS, CUS, and MRI examinations within 100 days of clinical-care liver biopsy. QUS parameters (attenuation coefficient and backscatter coefficient) were estimated using a reference phantom technique by two analysts independently. Three-point ordinal CUS scores intended to predict steatosis grade (1, 2, or 3) were generated independently by two radiologists on the basis of QUS features. PDFF was estimated using an advanced chemical shift–based MRI technique. Using histologic examination as the reference standard, ROC analysis was performed. Optimal attenuation coefficient, backscatter coefficient, and PDFF cutoff thresholds were identified, and the accuracy of attenuation coefficient, backscatter coefficient, PDFF, and CUS to predict steatosis grade was determined. Interobserver agreement for attenuation coefficient, backscatter coefficient, and CUS was analyzed. RESULTS CUS had 51.7% grading accuracy. The raw and cross-validated steatosis grading accuracies were 61.7% and 55.0%, respectively, for attenuation coefficient, 68.3% and 68.3% for backscatter coefficient, and 76.7% and 71.3% for MRI-estimated PDFF. Interobserver agreements were 53.3% for CUS (κ = 0.61), 90.0% for attenuation coefficient (κ = 0.87), and 71.7% for backscatter coefficient (κ = 0.82) (p < 0.0001 for all). CONCLUSION Preliminary observations suggest that QUS parameters may be more accurate and provide higher interobserver agreement than CUS for predicting hepatic steatosis grade in patients with NAFLD.

Novel quantitative assessment system of liver steatosis using a newly developed attenuation measurement method

“…The AUROC of ATT in this study for S ≥ 1, S ≥ 2, and S ≥ 3 was 0.79, 0.87, and 0.96, respectively, and its diagnosis accuracy of liver steatosis was comparable to those reported in previous studies using CAP; hence, the ATT measurement method appears clinically useful. Attenuation measurement methods different from ATT and CAP have also been reported . Although we cannot directly compare because the measurement method is different, our study includes more patients, and the prediction accuracy of steatosis grade is high.…”

Reader agreement and accuracy of ultrasound features for hepatic steatosis

“…As such, if more reproducible measurements of hepatic steatosis are needed, less subjective measures such as the hepatorenal index that can be applied to conventional ultrasound images may be used [20,21]. Also, quantitative ultrasound-based approaches such as the controlled attenuation parameter measured as part of vibration-controlled transient elastography [22–25] or more recent quantitative measurements of ultrasound backscatter and attenuation coefficients [26,27] may also be used. Other modalities such as advanced chemical-shift-encoded MRI may be required to quantify proton density fat fraction [27–32].…”

“…Also, quantitative ultrasound-based approaches such as the controlled attenuation parameter measured as part of vibration-controlled transient elastography [22–25] or more recent quantitative measurements of ultrasound backscatter and attenuation coefficients [26,27] may also be used. Other modalities such as advanced chemical-shift-encoded MRI may be required to quantify proton density fat fraction [27–32]. If conventional ultrasound is to be used for qualitative assessment, our findings suggest that radiologists should mainly focus on features with the highest reader agreement (e.g.…”

Optimization of region‐of‐interest sampling strategies for hepatic MRI proton density fat fraction quantification

“…This study was a single‐site secondary analysis of 391 patients (173 men, 218 women) with known or suspected NAFLD who underwent confounder‐corrected CSE 3T MRI for magnitude‐based fat quantification as part of prospective clinical studies from 2012 to 2016. Data represented in this work were obtained from subjects described in previously reported studies, but reanalyzed for the purposes outlined above. All patients signed written informed consent, and this study was approved by an Institutional Review Board and was compliant with the Health Insurance Portability and Accountability Act.…”