The anterior eye chamber: entry of the natural excretion pathway of gadolinium contrast agents?

OBJECTIVE: Previous studies provided evidence that gadolinium can be found in the aqueous chamber (AC) of the eye several hours post injection (p.i.) of gadolinium-based contrast agents (GBCAs). This study aimed to investigate whether gadolinium can be detected promptly after injection of a macrocyclic GBCA on contrast-enhanced T1-weighted MRI in the AC of children. METHODS: This retrospective study encompassed MRI of 200 healthy eyes of children suffering from retinoblastoma of the contralateral eye. MRI was performed with an orbital coil with the children in a state of general anesthesia. Differences of signal intensity ratios (SIRs) of the AC to the lens were determined between pre and post contrast-enhanced T1-weighted images (Dotarem(R), Guerbet, 0.1 ml/kg body weight, mean (standard deviation) p.i. time = 12:24 (+/- 2:31) min). RESULTS: A highly significant signal intensity increase was found in the AC of healthy eyes 12 min after GBCA injection (median SIR (interquartile range) = + 0.08 (0.05-0.12), p < 0.0001). In addition, gadolinium enhancement showed a strong negative correlation with children's age in multivariate analysis with adjustment for p.i. time (p < 0.0001). CONCLUSIONS: GBCA leakage into the AC of healthy infantile eyes was found promptly after injection. The negative correlation between patient age and GBCA enhancement might be explained by a maturation process of the blood-aqueous barrier or Schlemm's canal. Future studies should assess the duration and potential diagnostic applications as well as possible safety concerns of gadolinium presence in the AC. KEY POINTS: * Leakage of gadolinium-based contrast agent into the aqueous chamber of infantile eyes was found promptly after intravenous injection (p < 0.0001). * Gadolinium enhancement of the anterior eye chamber was negatively correlated with the children's age (p < 0.0001).