Fig. 4
a T1 phantom images of the HA-Gd2O3 NPs with different concentrations of total Gd ions. b The corresponding plots of 1/T1 against concentrations of total Gd ions. c In vivo T1 MR imaging and analysis of mice after intravenous injection of HA-Gd2O3 NPs as contrast agents. d Quantification of signal changes (SNR ratio) in the bladder and kidney at different time points after administration (n = 3). *p < 0.05