Iron Quantification Using Spectral CT-Based Material Decomposition Technique for Noninvasive Hepatic Fibrosis Staging: An Experimental Study

Background: Accurate staging is crucial for effective treatment of hepatic fibrosis (HF). This study evaluates whether spectral CT-derived liver iron concentration (LIC) quantification correlates with HF stages and validates its efficacy in diagnostic staging. Methods: One hundred seventy-five New Zealand white rabbits were included in the prospective study (35 normal controls; 140 HF models). Rabbits underwent spectral CT scans before modeling and at 4, 6, 8, 10, and 12 weeks. HF was staged by METAVIR system. Using iodine and water as reference materials paired with iron, the original LIC and the normalized LIC (NIC = LIC/aortic-iron) were measured. The material decomposition (MD) technique of spectral CT was used to quantify LIC and evaluate the correlation between HF stage and LIC. ANOVA, chi-square, and ROC were employed using SPSS, Python, and MedCalc. Results: One hundred fifty rabbits (30-per-stage, F0-F4) were selected. LICiron(iodine) and NICiron(iodine) in the noncontrast (NC) phase, and LICiron(water) and NICiron(water) in arterial phases (AP), increased with HF progression (p < 0.05) consistent with pathological results. Multiple LIC parameters exhibited significant differences in 126 comparisons (p < 0.05). ROC showed excellent diagnostic performance of NICiron(water)-AP across HF stages (AUC: 0.884-1.000), especially in distinguishing F1 from F0, F2, F3, and F4 (AUC: 0.979, 0.979, 0.918, 0.934). NICiron(iodine)-NC exhibited moderate efficacy in F0 versus F1 (AUC = 0.767) but high in other stages (AUC: 0.826-0.994). A multiparameter model achieved a macro-AUC of 0.9917. Conclusion: Spectral CT-based liver iron concentration quantification demonstrates a strong correlation with HF stages, providing precise HF staging and excellent diagnostic performance.