Eur Radiol Exp. 2026 May 6;10(1):60. doi: 10.1186/s41747-026-00720-3.
ABSTRACT
OBJECTIVE: Conventional coronary computed tomography angiography (CCTA) lumen assessment is hampered by the similar attenuation of iodine and calcium. We assessed the lumen for Gd-enhanced CCTA on high-resolution color Gd K-edge imaging using a clinical spectral photon-counting computed tomography (SPCCT) prototype in an anthropomorphic phantom.
MATERIALS AND METHODS: A hollow cylindrical coronary artery phantom (10-mm outer diameter, 5-mm inner diameter) containing five cylindrical calcifications of different densities (75, 100, 200, 400, and 800 mg/cm3 hydroxyapatite, deemed very low, low, medium, high, and very high, respectively) and equal size was scanned on a clinical SPCCT prototype using a clinical CCTA protocol. The artery model was filled with Gd mixed with saline to achieve 400 HU at 70 keV. The luminal area was compared with the physical area (i.e., 19.6 mm2), and spectral results were compared to conventional acquisition.
RESULTS: In the absence of calcification, physical lumen size was overestimated by 7% and 16% on color Gd K-edge and conventional images, respectively. In the presence of calcification, only color Gd K-edge images enabled the measurement of the lumen, i.e., 22.25 ± 0.43 mm2, 22.85 ± 1.77 mm2, 14.63 ± 1.17 mm2, and 15.37 ± 0.78 for very low to very high calcium density, respectively. Largest underestimation (-26%) and overestimation (16%) were shown for the high- and low-density calcification in comparison to physical size, respectively.
CONCLUSION: Color Gd K-edge imaging with Gd-enhanced CCTA outperformed conventional imaging in assessing the coronary lumen in both noncalcified and calcified vessels, whilst accuracy depends on the presence and density of calcifications.
RELEVANCE STATEMENT: In a phantom study, high-resolution color Gd K-edge imaging targeting Gd enabled accurate visualization of the coronary lumen in both calcified and noncalcified arteries, outperforming conventional CT angiography. In the presence of calcifications, only color Gd K-edge imaging provided objective lumen assessment, with accuracy influenced by calcium extent and density.
KEY POINTS: Color Gd K-edge Gd-enhanced CCTA using SPCCT is feasible in a coronary artery phantom. Color Gd K-edge imaging improves lumen assessment in calcified vessels. Color Gd K-edge imaging potentially enhances diagnostic precision and treatment planning for patients with coronary artery disease.
PMID:42090045 | DOI:10.1186/s41747-026-00720-3