MR lymphangiography using dendrimer-based contrast agents: A comparison at 1.5T and 3.0T

Abstract

Most macromolecular contrast agents (CAs) show lower r1 and higher r2 relaxivities at 3.0T than at 1.5T. MR lymphangiography in mice using a macromolecular G6 dendrimer-based CA was serially performed and compared at both 1.5T and 3.0T. The r1 and r2 relaxivities of the G6 CA were 25 and 78/s/mM at 1.5T and 17 and 82/s/mM at 3.0T, respectively. The lymph node (LN)-to-fat ratios (LN signal intensity (SI)/fat SI) of T1-weighted 3D-fast spoiled gradient-echo (3D-FSPGR) were 3.2 ± 0.4 (mean ± standard deviation (SD)) at 1.5T and 2.7 ± 0.3 at 3.0T (P = 0.021), and the LN-to-fat ratios of T2/T 1-weighted 3D-fast imaging employing steady-state acquisition with phase cycling (3D-FIESTA-C) were 1.8 ± 0.2 at 1.5T and 1.2 ± 0.4 at 3.0T (P = 0.003). Although 3D-FSPGR successfully delineated the LNs at both 1.5T and 3.0T, 3D-FIESTA-C at 3.0T failed to visualize the LNs. © 2007 Wiley-Liss, Inc.