Impact of CT Injector Technology and Contrast Media Viscosity on Vascular Enhancement: Evaluation in a Circulation Phantom

To assess the impact of piston-based peristaltic injection system technology and contrast media viscosity on achievable iodine delivery rates (IDRs) and vascular enhancement in a pre-clinical study. Four injectors were tested: MEDRAD Centargo, MEDRAD Stellant, CT Exprès , and CT motion using five contrast media [iopromide (300 and 370 mgI ml ), iodixanol 320 mgI ml , iohexol 350 mgI ml , iomeprol 400 mgI ml ]. Three experiments were performed evaluating achievable IDR and corresponding enhancement in a circulation phantom. Experiment I: Centargo provided the highest achievable IDRs with all tested contrast media ( < 0.05). Iopromide 370 yielded the highest IDR with an 18G catheter (3.15 gI/s); iopromide 300 yielded the highest IDR with 20G (2.70 gI/s) and 22G (1.65 gI/s) catheters ( < 0.05).Experiment II: with higher achievable IDRs, piston-based injectors provided significantly higher peak vascular enhancement (up to 48% increase) than the peristaltic injectors with programmed IDRs from 1.8 to 2.4 gI/s ( < 0.05).Experiment III: with programmed IDRs ( 1.5 gI/s) achievable by all injection systems, Centargo, with sharper measured bolus shape, provided significant increases in enhancement of 34-73 HU in the pulmonary artery with iopromide 370 ( < 0.05). The tested piston-based injection systems combined with low viscosity contrast media provide higher achievable IDRs and higher peak vascular enhancement than the tested peristaltic-based injectors. With equivalent IDRs, Centargo provides higher peak vascular enhancement due to improved bolus shape. This paper introduces a new parameter to compare expected performance among contrast media: the concentration/viscosity ratio. Additionally, it demonstrates previously unexplored impacts of bolus shape on vascular enhancement.