(a) Schematics of renal filteration of SAIO. SAIO filtered from the kidneys is collected in the bladder through the ureters and excreted into the urine. (b) MRI image showing urinary output from the kidneys towards the bladder through the ureters. (c) Rat bladder MRI image before and after the injection of SAIO. Gradual SAIO collection in the bladder is observed. SAIO collected in the bladder is excreted into the urine.