Tissue relaxation enhancement after intravenous administration of (ITCB-DTPA)-gadolinum conjugated albumin, an intravascular magnetic resonance imaging contrast agent.
Gadolinium-isothiocyanato-benzyl-diethylenetriamine pentaacetic acid (ITCB-DTPA-Gd), a derivative of Gd-DTPA, was multiply conjugated to bovine serum albumin (BSA). In the synthesis of BSA-(ITCB-DTPA-Gd) conjugate, none of the five carboxylate groups of DTPA is functionalized for protein-chelate linkage. The rationale for this modification is to improve the affinity for Gd3+. We obtained a high-stability constant for the complex, comparable to unbound Gd-DTPA. Also, the complex had a T1 relaxivity as high as 30.3 seconds-1mmol-1 at 29 MHz (at 24 degrees C). At this field strength, and T1 of rat blood declined 91% after injection of 300 mg/kg of BSA-(ITCB-DTPA-Gd), corresponding to a Gd dose of 0.02 mmol/kg, while at 0.86 MHz it declined 64%. The shortening of T1 in vitro of blood, as well as spleen, lungs, and kidneys, persisted for 60 minutes. Better enhancement on post-contrast magnetic resonance images of rats was obtained at 1.0 T than at 0.04 T. Tissues with rich vascularization and large venous structures were well displayed at the higher field.
Niemi
P
P
Department of Diagnostic Radiology, University of Turku, Finland.
Koskinen
S
S
Reisto
T
T
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D004353:Drug Evaluation, Preclinical; D004355:Drug Stability; D005682:Gadolinium / Q000008:administration & dosage / Q000493:pharmacokinetics; D019786:Gadolinium DTPA; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics; D004369:Pentetic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics; D051381:Rats; D011919:Rats, Inbred Strains; D012710:Serum Albumin, Bovine / Q000008:administration & dosage / Q000493:pharmacokinetics; D013997:Time Factors; D014018:Tissue Distribution
D003287:Contrast Media; D009942:Organometallic Compounds; D012710:Serum Albumin, Bovine; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA