Does a higher concentration of gadolinium chelates improve first-pass cardiac signal changes?

The purpose of this study was to evaluate first-pass cardiac signal changes with a higher concentrated gadoliniumchelate (gadobutrol) and its influenc e on bolus geometry, Phantom studies and in vivo first-pass cardiac studies were performed in rabbits (n = 8 experiments) under general anesthesia at 1.0 T using an ultrafast T1-weighted Turbofast low-angle shot (FLASH) seque nce (TR/TE 4.7/1.6 msec, alpha = 90 degrees) with a time resolution of 870 msec, Gadobutrol was injected as an intravenous bolus at two concentrations (0.5 and 1.0 mol Gd/L) and five doses (0.3, 0.15, 0.1, 0.055, and 0.03 mmo l Gd/kg bw). The blood-pool gadolinium compound gadopentetate dimeglumine-p olylysine (0.15, 0.075, 0.05, and 0.015 mmol Gd/kg bw, 0.5 mol Gd/L) and th e standard extracellular gadopentetate dimeglumine (0.1 and 0.05 mmol Gd/kg bw, 0.5 mol Gd/L) served as reference agents. Cardiac signal changes were calculated from serial signal intensity measurements. Maximum signal intens ity changes and best peak profiles during first pass of the right and left ventricle were observed with a dose of 0.03 mmol Gd/kg bw gadobutrol using T1-weighted Turbo-FLASH. At the low application volumes used, the higher co ncentration of 1.0 mol Gd/L gadobutrol did not increase the degree of signa l intensity changes or sharpen the bolus profile. First-pass cardiac signal changes using T1-weighted Tufbo-FLASH with the new extracellular contrast agent gadobutrol are best observed at a dose of 0.03 mmol Gd/kg bw. There i s no advantage to the concentrated formulation (1 mol Gd/L gadobutrol) when using small injection volumes. (C) 1999 Wiley-Liss, Inc.