Dynamic MRI of a hypovascularized liver tumor model: comparison of a new blood pool contrast agent (24-gadolinium-DTPA-cascade-polymer) with gadopentetate dimeglumine.

We evaluated the enhancement properties of a new blood pool contrast agent (24-gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]-cascade-polymer) in comparison with gadopentetate dimeglumine in 24 rabbits with an experimentally induced VX-2 liver tumor. Dynamic MRI of the liver was performed before, immediately after, and within 15 seconds to 30 minutes after contrast agent administration. Relative signal intensities and contrast-to-noise ratios (CNRs) of both agents were evaluated. After blood pool agent administration a significantly higher CNR between liver and tumor was observed within 2 to 30 minutes after injection as compared with the CNR after gadopentetate dimeglumine. Within 4 to 30 minutes after injection of gadopentetate dimeglumine, the relative signal intensities of tumor were significantly higher than after administration of the blood pool agent. In conclusion, the new blood pool contrast agent demonstrated a significantly better CNR of the experimental hypovascularized liver tumor than gadopentetate dimeglumine.