Selective use of low-osmolality contrast agents for i.v. urography and CT: safety and effect on cost

The purpose of this study was to determine if the selective use of low-osmolality contrast material for excretory urography and CT is safe and if it saves money.

At the University Medical Center in Tucson, a questionnaire was developed to identify high-risk patients who would benefit from the use of a low-osmolality contrast agent. High-risk patients were defined as those with a history of a reaction to contrast material, severe allergies, asthma, severe cardiac disease, multiple myeloma, sickle cell disease, polycythemia, pheochromocytoma, or renal impairment. Beginning in March 1993, the questionnaire was given to all adult outpatients scheduled for daytime excretory urography and routine CT studies of the head and body. Only patients identified as high risk were given a low-osmolality (non-ionic) contrast agent. All other patients received high-osmolality (ionic) contrast material. The contrast agent chosen for a patient was determined by the person administering the questionnaire, usually a radiologic technologist.

From March 1993 through December 1993, 1114 adult daytime outpatient excretory urographic and contrast-enhanced CT studies were examined at our institution. In 235 (21%) of the studies, a low-osmolality agent was used and in 879 (79%) studies, a high-osmolality agent was used. This represented a reduction in the use of low-osmolality agents from more than 90% of patients to 21%, an annual cost reduction from $288,000 to $60,480. We observed no untoward reactions to contrast material that could be specifically attributed to the increased use of high-osmolality agents.

Selective use of low-osmolality contrast agents during excretory urography and CT can provide substantial cost savings and is not associated with a significant risk of major complications.