Iodine material density images in dual-energy CT: quantification of contrast uptake and washout in HCC
To determine the diagnostic potential of Material Density (MD) iodine images in dual-energy CT (DECT) for visualization and quantification of arterial phase hyperenhancement and washout in hepatocellular carcinomas compared to magnetic resonance imaging (MRI).
Materials and Methods
The study complied with HIPAA guidelines and was approved by the ethics committee of the institutional review board. Thirty-one patients (23 men, 8 women; age range, 36–87 years) with known or suspected Hepatocellular Carcinoma (HCC) were included. All of them underwent both single-source DECT and MRI within less than 3 months. Late arterial phase and portal venous phase CT imaging was performed with dual energies of 140 and 80 kVp, and virtual monoenergetic images (at 65 keV) and MD-iodine images were generated. We determined the contrast-to-noise ratio (CNR) for HCC in arterial phase and portal venous phase images. In addition, we introduced a new parameter which combines information of CNR in arterial and portal venous phase images into a single ratio (combined CNR). All parameters were assessed on monoenergetic 65 keV images, MD-iodine images, and MRI. Paired t test was used to compare CNR values in Mono-65 keV, MD-iodine, and MR images.
CNR was significantly higher in the MD-iodine images in both the arterial (81.87 ± 40.42) and the portal venous phases (33.31 ± 27.86), compared to the Mono-65 keV (6.34 ± 4.23 and 1.89 ± 1.87) and MRI (30.48 ± 25.52 and 8.27 ± 8.36), respectively. Combined CNR assessment from arterial and portal venous phase showed higher contrast ratios for all imaging modalities (Mono-65 keV, 8.73 ± 4.03; MD-iodine, 119.87 ± 52.94; MRI, 34.87 ± 27.34). In addition, highest contrast ratio was achieved in MD-iodine images with combined CNR evaluation (119.87 ± 52.94, P < 0.001).
MD-iodine images in DECT allow for a quantitative assessment of contrast enhancement and washout, with improved CNR in hepatocellular carcinoma in comparison to MRI.
KeywordsDual-energy CT Spectral CT Hepatocellular carcinoma Iodine images Washout
Compliance with ethical standards
There was no funding for this study.
Conflict of interest
All authors declare that there is no conflict of interest.
This study was in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Approval for this HIPPA-compliant retrospective study and waiver of informed consent was obtained by the Institutional Review Board.
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