Low-osmolar monomeric versus iso-osmolar dimeric contrast media: An intra-individual comparison in CT angiography using an animal model

Introduction: The aim of this study was to compare intra-individual contrast enhancement in multidetector-row computed tomography using the low-osmolar monomeric iopromide 300 and the iso-osmolar dimeric iodixanol 320. Methods: Repeated computed tomography scanning of the chest of five pigs was performed under standardised conditions using iopromide 300 (300 mg I/mL) and iodixanol 320 (320 mg I/mL) with an identical iodine delivery rate of 1.5 g I/sec and a total iodine dose of 300 mg/kg body weight. Time-enhancement curves were computed, and pulmonary and aortic peak enhancement, time-to-peak and plateau time above 300 Hounsfield units (HU) were analysed. Results: Intra-individual comparison revealed no statistically significant differences in contrast enhancement between the iopromide 300 and iodixanol 320 in the pulmonary artery and the aorta (620 vs 552 HU; P = 0.13). There was no significant difference between the two CM in the plateau time at the pulmonary artery and the aorta (P = 0.75 and P = 0.24, respectively). Aortic peak time was significantly earlier with iopromide 300 than with iodixanol 320 (P = 0.004). Conclusions: Low-osmolar monomeric and iso-osmolar dimeric CM provide a similar and suitable vascular contrast enhancement.