Human comparative study of zinc and copper excretion via urine after administration of magnetic resonance imaging contrast agents.
OBJECTIVE
To evaluate the in-vivo pharmacokinetics of magnetic resonance imaging (MRI) contrast agents, the excretion of zinc and copper via urine was studied for three gadolinium (Gd) chelate complexes.


METHODS
Urine samples were taken before, three hours, and six hours after intravenous administration of Gd-DTPA-BMA, Gd-DTPA, and Gd-DOTA at 0.2 ml/kg to five patients each who underwent contrast-enhanced MRI. Five patients who had non-contrast MRI were evaluated as controls. Urine was assayed for quantitative analysis of zinc and copper using atomic absorption analysis.


RESULTS
Gd-DTPA-BMA caused the highest increase in zinc excretion among the three agents, 1,795 +/- 1,273 microg at 3 hours and 985 +/- 434 microg at 3 to 6 hours. Gd-DOTA did not cause a significant increase in zinc excretion, 75 +/- 39 microg at 3 hours and 78+/-65 microg at 3 to 6 hours. Gd-DTPA caused a moderate increase in zinc excretion, 665 +/- 240 microg at 3 hours and 378 +/- 173 microg at 3 to 6 hours. Excretion of copper did not show a significant difference among the three agents.


CONCLUSIONS
Gd-DOTA was found to be the most kinetically inert among the three agents tested. The difference in zinc excretion among the MR contrast agents is possibly related to in-vivo transmetallation of the Gd chelate complexes correlated with variable stability of the contrast agents. The large amount of excess ligands contained in some MR contrast agents was also considered to be responsible for the increase of urinary zinc excretion.
Kimura
Junko
J
Department of Radiology, Aichi Medical University, Japan.
Ishiguchi
Tsuneo
T
Matsuda
Joe
J
Ohno
Ryota
R
Nakamura
Atsushi
A
Kamei
Seiji
S
Ohno
Kazuko
K
Kawamura
Toshiki
T
Murata
Katsuhito
K
D003287:Contrast Media / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D003300:Copper / Q000652:urine*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D006571:Heterocyclic Compounds / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000737:chemistry / Q000493:pharmacokinetics; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors; D015032:Zinc / Q000652:urine*
D003287:Contrast Media; D006571:Heterocyclic Compounds; C112669:gadolinium DOTA meglumine; D008536:Meglumine; D003300:Copper; C064925:gadodiamide; D015032:Zinc; D019786:Gadolinium DTPA