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. 2023 Oct;128(10):1174-1180.
doi: 10.1007/s11547-023-01693-8. Epub 2023 Aug 12.

Ultrasound-derived fat fraction for detection of hepatic steatosis and quantification of liver fat content

Riccardo De Robertis  1   2 , Flavio Spoto  3   4 , Daniele Autelitano  3   4 , Daniela Guagenti  3   4 , Antonia Olivieri  3   4 , Piero Zanutto  3   4 , Greta Incarbone  3   4 , Mirko D'Onofrio  3   4
Affiliations

Ultrasound-derived fat fraction for detection of hepatic steatosis and quantification of liver fat content

Riccardo De Robertis et al. Radiol Med. 2023 Oct.

Abstract

Purpose: To compare ultrasound (US) and US-derived fat fraction (UDFF) with magnetic resonance proton density fat fraction (MRI-PDFF) for the detection of hepatic steatosis and quantification of liver fat content.

Materials and methods: Between October and December 2022, 149 patients scheduled for an abdominal MRI agreed to participate in this study and underwent MRI-PDFF, US and UDFF. Inclusion criteria were: (a) no chronic liver disease or jaundice; (b) no MRI motion artifacts; (c) adequate liver examination at US. Exclusion criteria were: (a) alcohol abuse, chronic hepatitis, cirrhosis, or jaundice; (b) MRI artifacts or insufficient US examination. The median of 10 MRI-PDFF and UDFF measurements in the right hepatic lobe was analyzed. UDFF and MRI-PDFF were compared by Bland-Altman difference plot and Pearson's test. Sensitivity, specificity, positive and negative predictive values, accuracy, and area under the receiver-operator curve (AUC-ROC) of US and UDFF were calculated using an MRI-PDFF cut-off value of 5%. p values ≤ 0.05 were statistically significant.

Results: 122 patients were included (61 men, mean age 60 years, standard deviation 15 years). The median MRI-PDFF value was 4.1% (interquartile range 2.9-6); 37.7% patients had a median MRI-PDFF value ≥ 5%. UDFF and MRI-PDFF had high agreement (p = 0.11) and positive correlation (⍴ = 0.81, p < 0.001). UDFF had a higher diagnostic value than US for the detection of steatosis, with AUC-ROCs of 0.75 (95% CI 0.65, 0.84) and 0.53 (95% CI 0.42, 0.64), respectively.

Conclusions: UDFF reliably quantifies liver fat content and improves the diagnostic value of US for the detection of hepatic steatosis.

Keywords: Fatty liver; Liver; Magnetic resonance; Non-alcoholic fatty liver disease; Ultrasound.

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Conflict of interest statement

The authors have no relevant financial or non-financial interests to disclose.

Figures

Fig. 1
Fig. 1
Quantification of liver fat content in a 31-year-old man with NAFLD. a Fat fraction map: a circular ROI is visible in liver segment 5; the overall median MRI-PDFF value was 25%. b B-mode US and quantification of the hepatorenal index: liver echogenicity is higher than the right kidney cortex; visualization of the diaphragm and posterior surface of the right hepatic lobe is decreased; the ratio of the mean brightness of liver (1) and kidney (2) ROIs was 1.91; c UDFF measurement: a ROI box is visible in liver segment 5; the overall median UDFF value was 24%
Fig. 2
Fig. 2
Quantification of liver fat content in a 58-year-old woman without steatosis. a Fat fraction map: a circular ROI is visible in liver segment 7; the overall median MRI-PDFF value was 4%. b B-mode US and quantification of the hepatorenal index: liver echogenicity is comparable to the right kidney cortex; the ratio of the mean brightness of liver (1) and kidney (2) ROIs was 0.77; c UDFF measurement: a ROI box is visible in liver segment 7; the overall median UDFF value was 4%
Fig. 3
Fig. 3
Results of Bland–Altman analysis. The mean difference in liver fat content measured by PDFF and UDFF is 0.35 (solid line). The upper and lower 95% limits of agreement were 4.85 and − 5.63, respectively (dashed lines)
Fig. 4
Fig. 4
Scatter plot showing the correlation in liver fat content (%) values measured between UDFF and PDFF. The linear regression indicates a strong correlation between the two methods (⍴ = 0.808, p < 0.001). The dashed lines are the 95% limits of agreement
Fig. 5
Fig. 5
AUC-ROC curves of UDFF (solid line) and B-mode US (dashed line) for detection of steatosis
See this image and copyright information in PMC

Comment in

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