Advances in Liver Fat Volume Fraction Assessment Using Dual-Energy CT

Research conducted at Cedars-Sinai Medical Center has made significant advancements in liver fat volume fraction (FVF) assessment using dual-energy computed tomography (CT). The study aimed to analyze the relationship between FVF and Hounsfield units (HU) in unenhanced fatty lesions and identify optimal settings to minimize FVF quantification errors. The findings indicate that the validity of the linear relation for FVF-HU is x-ray beam energy and virtual monochromatic imaging (VMI) energy-dependent. The research concluded that the use of VMI with wider dual energy spectral separation showed the best accuracy, with a root-mean-square (RMS) error of 2.5% for the medium-sized phantom.

Key Takeaways:

• The study found that the FVF-HU relationship is x-ray beam energy and VMI energy-dependent, impacting FVF assessment accuracy.
• For the medium-sized phantom, the use of VMI with wider dual energy spectral separation showed an RMS error of 2.5% and a maximum individual FVF error of 10%.
• The research identified optimal settings for DECT, including the use of FKVS CT, four VMI settings, and a CTDI of 14.5 mGy, resulting in lower RMS errors compared to SECT.
• The study also found that the use of single energy at 140 kV on the FKVS CT showed the best estimate for the large phantom, albeit with a RMS error of 9%.
• The findings suggest that VMI with wider dual energy spectral separation is a promising approach for accurate FVF assessment.
• The research has been peer-reviewed and published in Medical Physics.

Statistics:

• RMS FVF estimation errors from the linearity assumption were slightly higher than 9% with the SECT at 120 kV and CTDI = 14.5 mGy on both units.
• Maximum individual FVF errors were 16.5%-23% at FVF 10%.
• The smallest RMS error (5%) was achieved at 90 and 100 keV with FKVS CT.
• The lowest RMS error (2.5%) was obtained at 120 and 130 keV with DSCT and spectra 80/Sn 150 kV.
• For the large phantom, the RMS error of 9.2% was obtained using the linear model at single energy of 140 kV.
• The maximum individual FVF error of 20% occurred at 5% FVF.

Sources:

• "Liver fat volume fraction assessment in medium and large anthropomorphic phantoms-dual energy virtual monochromatic imaging versus single-energy CT." Medical Physics, 2025;52(9).
• Xinhua Li, Dept. of Imaging, Cedars-Sinai Medical Center, Los Angeles, California, United States.
• American Association of Physicists in Medicine - www.aapm.org.
• Medical Physics - online.medphys.org/
• Wiley, 111 River St, Hoboken 07030-5774, NJ, USA.