INNOCUITY OF AGENTS FOR RADIOCONTRAST ENHANCEMENT OF URINARY-TRACT STONES

Objectives. Mineral kidney stones are frequently difficult to detect d ue to their radiotranslucency. We have recently developed a method tha t enhances the visibility of such stones by retrograde infusions of ce rtain heavy metal salt solutions such as cesium or lanthanide gadolini um. This report describes toxicologic studies carried out on the use o f those contrast agents to introduce this technique eventually into cl inical trials. Methods. Systemic absorption was assessed in dogs throu gh infusion of radioactive contrast agent into the renal pelvis with o r without ureteral obstruction. Radioactivity in urine and blood was m onitored. Local toxicity was studied in animals infused with the contr ast agent at intervals up to 4 weeks. Results. Reabsorption studies un der high intrapelvic pressures (70 cm H2O or higher), demonstrated rea bsorption of cesium. However, at normal intrapelvic pressures, only a moderate reabsorption of cesium was observed. No gadolinium reabsorpti on was detected even at high intrapelvic pressures. Histopathologic st udies showed no major urothelial lesions but only a transient inflamma tory reaction that was undetectable 4 weeks following exposure to gado linium salts. Conclusions. Gadolinium salt solutions are good positive radiocontrast agents for mineral kidney stones without having serious toxic effects or systemic reabsorption.