STEADY-STATE AND DYNAMIC MR-ANGIOGRAPHY WITH MS-325 - INITIAL EXPERIENCE IN HUMANS

PURPOSE: To evaluate the imaging performance and patient tolerance of a blood-pool contrast agent (MS-325) for magnetic resonance (MR) angio graphy. MATERIALS AND METHODS: Imaging of peripheral and carotid vesse ls was performed in seven healthy volunteers in a phase I clinical tri al of the gadolinium chelate MS-325. Each volunteer received an intrav enous injection of 0.05 mmol/kg MS-325 over 30 seconds. Dynamic (arter ial phase) and steady-state (arterial-venous phase) three-dimensional gradient-echo MR angiograms were acquired during, immediately after, a nd approximately 50 minutes after injection. Images were ranked (1 [po or] to 5 [excellent]) for overall image quality, and signal-to-noise r atio (S/N) and contrast-to-noise ratio (C/N) were measured by using st andard techniques. RESULTS: All volunteers tolerated the procedure wel l. The MS-325-enhanced studies demonstrated intense vascular signal. M ean peripheral arterial C/N was 12.9 +/- 4.8 (standard deviation), 78. 8 +/- 29.4, 46.1 +/- 10.9, and 41.9 +/- 14.1 for the two-dimensional ( 2D) time-of-flight (TOF) and the contrast material-enhanced dynamic, e arly steady-state, and late steady-state images, respectively. Image q uality of steady-state postcontrast images was statistically significa ntly (P < .02) higher than that of 2D TOF images. Image quality of ear ly and late postcontrast images was similar, but a small (10%) decreas e in C/N was noted from early to late images. CONCLUSION: MS-325 provi des excellent vascular and selective arterial enhancement during dynam ic MR angiography. The long blood residence time also allows acquisiti on of steady-state images of the arteries and veins with excellent spa tial resolution.