Contrast-enhanced magnetic resonance angiography - P792 blood pool agent versus Gd-DOTA in rabbits at 3.0 T versus 1.5 T

Purpose: To assess the gadolinium-based macromolecular intravascular contrast agent P792 for magnetic resonance angiography (MRA) at magnetic field strengths of 3.0 T, in comparison to 1.5 T, in rabbits. Materials and Methods: Eleven female New Zealand rabbits of the same age served as the animal model. Dose relationship testing was performed with 2 doses (13 and 25 [mu mol/kg; n = 4 per group) of P792 as compared with a single dose (100 mu mol/kg; n = 3) of gadoterate meglumine (Gd-DOTA). All animals underwent contrast-enhanced MRA of the abdominal aorta and its branches on 2 occasions separated by 72 hours. The particular doses were administered in random order. Contrast-enhanced MRA was performed on 3.0 and 1.5 T whole-body MR systems, using a fast 3D spoiled gradient recalled echo sequence. Data acquisition was performed before and up to 10 minutes after administration of intravenous contrast material. Image quality was judged on a 4-point-Likert scale. Signal-to-noise and contrast-to-noise measurements were performed; statistical differences (P < 0.05) between the groups were determined. Results: P792 and Gd-DOTA yielded high-quality MR angiograms in rabbits in all cases. Although image quality within the first 3 minutes after contrast material administration was equal for both agents, P792 at a dose of 25 mu mol/kg was considered superior to Gd-DOTA at the later time points. Signal-to-noise and contrast-to-noise values of the higher dose of P792 were statistically significantly higher than those of Gd-DOTA in the post-bolus phase. Conclusions: P792 seems to be well suited for high-quality early phase and equilibrium phase MRA in rabbits at a field strength of 3.0 T, on the basis of this initial evaluation in an animal model.