Harald Kramer MD, Presenter: Nothing to Disclose

Mark A. Kliewer MD, Abstract Co-Author: Nothing to Disclose

Perry J. Pickhardt MD, Abstract Co-Author: Co-founder, VirtuoCTC, LLC Stockholder, Cellectar Biosciences, Inc

Diego Hernando PhD, Abstract Co-Author: Nothing to Disclose

Guang-Hong Chen PhD, Abstract Co-Author: Research funded, General Electric Company Research funded, Siemens AG Research funded, Varian Medical Systems, Inc Research funded, Hologic, Inc

Scott Brian Reeder MD, PhD, Abstract Co-Author: Institutional research support, General Electric Company Institutional research support, Bracco Group

The hallmark feature of non-alcoholic fatty liver disease (NAFLD) is the accumulation of triglycerides within hepatocytes (steatosis), which can lead to inflammation, fibrosis, and cirrhosis. Magnetic resonance spectroscopy (MRS) is widely considered to be the reference standard for accurate non-invasive quantification of fat content in the liver. The purpose of this study was to evaluate the accuracy of quantitative confounder-corrected chemical shift-encoded MRI, dual-energy computed tomography (CT) and ultrasound (US) to quantify hepatic steatosis in comparison to MRS.

44 patients (57±5 years, 19m/25f, 27±7 BMI) scheduled for non-contrast enhanced screening CT colonography (CTC) were recruited for this prospective comparative study. All patients underwent MRS, MRI and US within 2 hours of CTC. 3 MRS voxels were placed in the left and right lobes of the liver; CT, MRI and US measurements were subsequently co-localized. For CT (DECT, 80/140kV) attenuation (HU) and fat-density (FD) derived material decomposition images were reconstructed and HU and FD recorded. For MRI, proton density fat-fraction (PDFF) measured from the quantitative chemical shift-encoded method (IDEAL-IQ) were recorded and for US, shear-wave velocity was recorded. Data were analyzed using linear regression for each technique compared to MRS. 2-sided paired Student t-tests (0.05 significance level) were used to test the hypothesis that the slope coefficient is zero.

There was excellent correlation and agreement between MRS-PDFF vs MRI-PDFF (r2=0.88-0.97, p0.05, slope -0.01±0.02, intercept 1.66±0.174).

In this comparative effectiveness study of three advanced non-invasive biomarkers of hepatic steatosis quantitative chemical shift encoded MRI and CT attenuation showed excellent correlation to MRS and can serve as accurate biomarkers for steatosis. Material decomposition with DECT (CT-FD) did not improve the accuracy of fat quantification over conventional attenuation. US is accepted as a biomarker for quantifying liver fibrosis but had poor accuracy for liver-fat quantification. A major benefit of MRI and CT is the evaluation of the entire liver tissue instead of only small samples like in biopsy and MRS.

Because fatty liver disease affects an increasing number of patients there is a need for accurate quantitative biomarkers to access this disease.

Kramer, H, Kliewer, M, Pickhardt, P, Hernando, D, Chen, G, Reeder, S, Accuracy of Liver Fat Quantification by CT, MRI and US: A Prospective Comparison with Magnetic Resonance Spectroscopy (MRS).  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010351.html