Gadolinium Retention in the Rat Brain: Assessment of the Amounts of Insoluble Gadolinium-containing Species and Intact Gadolinium Complexes after Repeated Administration of Gadolinium-based Contrast Agents

After repeated intravenous administration in rats, gadoteridol was 10 times less retained than gadodiamide, and all of the detected gadolinium was in the form of intact soluble gadolinium complex; exposure to gadodiamide resulted in retention of both soluble and insoluble gadolinium-containing species, with insoluble materials dominating.