title: 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/T1-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.
authors.affiliation: Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1088, USA.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Hama
authors.forename: Marcelino
authors.initials: M
authors.lastname: Bernardo
authors.forename: Celeste A S
authors.initials: CA
authors.lastname: Regino
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Koyama
authors.forename: Martin W
authors.initials: MW
authors.lastname: Brechbiel
authors.forename: Murali C
authors.initials: MC
authors.lastname: Krishna
authors.forename: Peter L
authors.initials: PL
authors.lastname: Choyke
authors.forename: Hisataka
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000493:pharmacokinetics*; D050091:Dendrimers; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D007091:Image Processing, Computer-Assisted; D008220:Lymphography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D011073:Polyamines / Q000493:pharmacokinetics*
chemical_list: D003287:Contrast Media; D050091:Dendrimers; C104700:PAMAM Starburst; D011073:Polyamines; D019786:Gadolinium DTPA