Simultaneous hepatic iron and fat quantification with dual-energy CT in a rabbit model of coexisting iron and fat

Abstract

Background: Liver iron and fat are often co-deposited, synergistically aggravating the progression of chronic liver disease. Accurate determination of liver iron and fat content is helpful for patient management.To assess the accuracy of hepatic iron/fat decomposition using dual-energy computed tomography (DECT) for simultaneously quantifying hepatic iron and fat when both are present.Methods: Sixty-eight New Zealand rabbits on a high-fat/cholesterol diet plus iron injections were used to establish a model of coexisting hepatic iron/fat. Abdominal imaging was performed using dual-source DECT.The iron and fat fractions (Iron-CT and Fat-CT , respectively) were calculated using a 3-material decomposition algorithm. The spectroscopic liver iron concentration (LIC) grading (normal, mild, moderate, severe, and massive iron overload) and the histopathological fat fraction (Fat-ref) grading (normal, mild, moderate, severe steatosis) were used as references. Correlations between the DECT parameters and the references were analyzed. Hepatic iron/fat quantification equations were established and validated. Analysis of covariance was used to assess the influence of fat on iron measurements and vice versa.Results: Iron-CT highly correlated with LIC (r=0.94, P<0.001), and Fat-CT highly correlated with Fatref (r=0.88, P<0.001). Both the Iron-CT -and Fat-CT -derived LIC and fat fraction showed good agreement with spectroscopy/histology. The linear relationship between Iron-CT and spectroscopic LIC was not affected by the grade of hepatic fat (F=1.93, P=0.16). The linear relationship between Fat-CT and Fatref was unaffected by hepatic iron grades from normal to severe (F=0.18, P=0.91). However, with massive iron overload [>15.0 mg Fe/g (270 μmol/g)] the regression began to deviate, causing fat underestimation (F=5.50, P=0.04).Conclusions: Our DECT-based iron/fat decomposition algorithm accurately measured hepatic iron and fat when both were present in a rabbit model. Hepatic fat may be underestimated when there is massive iron overload.

Dual-source dual-energy computed tomography-derived quantitative parameters combined with machine learning for the differential diagnosis of benign and malignant thyroid nodules

“…The recent technical advance of dual-source dualenergy CT (DS-DECT) has improved the situation, as this method uses two different X-ray sources, allowing for the simultaneous use of two different energies to achieve potential tissue differentiation. The advanced quantitative technique can separate several types of substances, such as water, iodine, calcium, uric acid, and fat (8)(9)(10)(11). Quantitative iodine parameters have been considered a promising tool for distinguishing malignant from benign tumors (12)(13)(14)(15).…”

Dual-Energy Computed Tomography in Diffuse Liver Diseases

“…Unlike SECT, which underestimates fat in the presence of iron and vice versa, several phantom and animal studies have shown that DECT can accurately quantify iron, even in the presence of fat 52 82 83 and vice versa. 52 83 84 In contrast, several other studies have suggested that iron and fat affect the measurement of each other on DECT.…”

“…Unlike SECT, which underestimates fat in the presence of iron and vice versa, several phantom and animal studies have shown that DECT can accurately quantify iron, even in the presence of fat 52 82 83 and vice versa. 52 83 84 In contrast, several other studies have suggested that iron and fat affect the measurement of each other on DECT. 85 86 87 A recent study also suggested that the phase of contrast-enhanced scan (arterial, portal venous, and delayed) significantly affects the hepatic iron measurements on DECT.…”

Fat quantification in dual-layer detector spectral CT: How to handle iron overload, varying tube voltage and radiation dose Indices

“…Therefore, valid fat quantification in the presence of iron is necessary. While it is known that fat contents are underestimated in the presence of iron in dual-source CT [ 16 , 17 ], the potential impact of iron on dlCT fat quantification and how to deal with it was not clear, yet.…”