Clinical phase I study of Gd-DTPA as MRI contrast agent

We performed a phase I study of Gd-DTPA which had been developed as contrast agent for magnetic resonance imaging (MRI). Injection volume were 0.05, 0.10, 0.20 mmol/kg of Gd-DTPA for six normal volunteers respectively. We did not see any complaints, clinical symptoms, and significantly abnormal laboratory data. The blood concentration of Gd-DTPA subsequently decreased with a half life of 2 - 14 minutes in the first (distribution) phase and 0.93 - 1.86 hours in the second (excretion) phase. Contrast enhancement of the kidney and urine in the bladder could be seen at least for 20 - 50 minutes. A peak of contrast enhancement of the renal parenchyma was from five to ten minutes after intravenous injection. (author)