Safety and preliminary findings with the intravascular contrast agent NC100150 injection for MR coronary angiography

In this Phase I clinical study, a novel ultrasmall superparamagnetic iron o xide contrast agent, NC100150 Injection (Nycomed Imaging, Oslo, Norway, a p art of Nycomed Amersham), was used in two-dimensional magnetic resonance co ronary angiography (MRCA). Safety and imaging data were acquired from 18 he althy male volunteers at both 0.5 and 1.5 T, before and after the administr ation of NC100150 Injection. Through-plane and in-plane images of the right coronary artery were analyzed. The postcontrast imaging sequences used pre pulses and a high hip angle, to introduce T1 weighting. At 1.5 T (TE 2.6 ms ec), the through-plane coronary artery signal-to-noise ratio (SNR) (P = 0.0 4), coronary artery-to-fat signal difference-to-noise ratio (SDNR) (P = 0.0 01), coronary artery-to-myocardium SDNR (P < 0.001), and coronary artery de lineation (P < 0.001) were improved by the administration of NC100150 Injec tion. For in-plane imaging, coronary artery delineation improved, but there were no significant changes in the SNR and SDNR. At 0.5 T, with the longer TE (6.7 msec) imaging sequence used, there was a reduction in the SNR (P = 0.01), the fat SDNR (through-plane P = 0.02: in-plane P = 0.25), and the c oronary artery diameter (P < 0.01 in both imaging planes). There was a tren d toward improvement in the myocardial SDNR and coronary artery delineation . In conclusion, NC100150 Injection was given safely to 18 healthy subjects , with no major adverse reactions. Coronary artery delineation was improved in both imaging planes at 1.5 T with a trend toward improvement at 0.5 T. At 1.5 T, with a short TE imaging sequence, the marked T1 shortening effect s of NC100150 Injection were dominant, leading to an improvement in the qua ntitative parameters for the through-plane images. At 0.5 T, with a longer TE imaging sequence, the T2* effects of the contrast agent played a role in reducing the quantitative image parameters. With further optimization of i maging sequences, to take advantage of the long-lived intravascular T1 shor tening effect of NC100150 Injection, further improvements in MRCA will be p ossible. J. Magn. Reson. Imaging 1999; 9:220-227. (C) 1999 Wiley-Liss, Inc.