Using Dual-source Photon-counting Detector CT to Simultaneously Quantify Fat and Iron Content: A Phantom Study

Rationale and Objectives To evaluate the feasibility of using photon-counting detector computed tomography (PCD CT) to simultaneously quantify fat and iron content Materials and Methods Phantoms with pure fat, pure iron and fat-iron deposition were scanned by two tube voltages (120 and 140 kV) and two image quality (IQ) settings (80 and 145). Using an iron-specific three-material decomposition algorithm, virtual noniron (VNI) and virtual iron content (VIC) images were generated at quantum iterative reconstruction (QIR) strength levels 1–4. Results Significant linear correlations were observed between known fat content (FC) and VNI for pure fat phantoms (r = 0.981–0.999, p < 0.001) and between known iron content (IC) and VIC for pure iron phantoms (r = 0.897–0.975, p < 0.001). In fat–iron phantoms, the measurement for fat content of 5–30% demonstrated good linearity between FC and VNI (r = 0.919–0.990, p < 0.001), and VNI were not affected by 75, 150, and 225 µmol/g iron overload (p = 0.174–0.519). The measurement for iron demonstrated a linear range of 75–225 µmol/g between IC and VIC (r = 0.961–0.994, p < 0.001) and VIC was not confounded by the coexisting 5%, 20%, and 30% fat deposition (p = 0.943–0.999). The Bland–Altman of fat and iron measurements were not significantly different at varying tube voltages and IQ settings (all p > 0.05). No significant difference in VNI and VIC at QIR 1–4. Conclusion PCD CT can accurately and simultaneously quantify fat and iron, including scan parameters with lower radiation dose.