Balancing Image Quality and Iodine Intake: Insights from CT Spectral Imaging of the Portal Vein

BACKGROUND Portal vein tumor thrombus (PVTT) is a critical complication in hepatocellular carcinoma (HCC). Spectral computed tomography (CT) is increasingly used to enhance the diagnosis of such conditions. This study examines the effect of different iodine concentrations in contrast media on portal vein image quality and iodine intake using spectral CT to improve imaging techniques. MATERIAL AND METHODS A total of 88 patients were divided into 3 groups based on iodine concentration in contrast media: Group A (300 mgI/mL, n=30), Group B (320 mgI/mL, n=28), and Group C (350 mgI/mL, n=30). Each underwent a GSI scan with an injection rate of 4.5 mL/s and a dose of 1.5 mL/kg. Eleven sets of 40-140 keV images were reconstructed for each group. CT value, image noise, contrast noise ratio (CNR), signal-to-noise ratio (SNR), and subjective image scores of intra-hepatic and extra-hepatic portal veins were analyzed. Optimal monochromatic levels and iodine intake were assessed for each group. RESULTS The optimal monochromatic level for portal veins was between 80 keV-110 keV across groups. Significant differences were noted in CT values and image noise among groups (P<0.05), but not in CNR, SNR, or subjective scores (P>0.05). Iodine intake was reduced by 21.29% in Group A and 14.60% in Group B compared to Group C. CONCLUSIONS GSI scans with low-concentration contrast media effectively reduce iodine intake while maintaining image quality during liver CT-enhanced scans.