Are patients willing to help reduce contrast material in the environment? The outpatient use of urine bags after contrast-enhanced computed tomography.

Objectives: We studied the willingness of outpatients to reduce the environmental impact of contrast media by using urine bags to collect excreted contrast material after contrast-enhanced computed tomography (ceCT).

Materials and methods: In this prospective single-center cohort study, we provided consecutive outpatients undergoing ceCT with information about contrast material excretion. We then offered urine bags to collect their urine for the first four consecutive urination sessions after the ceCT examination. An absorbent pad within these bags transforms the urine from liquid to solid so that the bags can be disposed of via the household waste system to avoid water contamination. Participants were asked to complete a questionnaire-based telephone interview after ceCT.

Results: Of the 671 consecutive outpatients undergoing ceCT, 503 patients (75%) participated in the study, of whom 476 participants (mean age, 63 years; range, 20-88 years) successfully underwent a telephone interview. 455 of 476 patients (96%) had used at least one urine bag; 84% had used 3 or 4 urine bags. Time between ceCT and use of the final urine bag averaged 9.46 h (range, 0.1-28.5 h). 434 patients (91%) were "willing to collaborate on solutions to reduce contrast agent residues in water." 380 patients (80% of participants) stated to "definitely use the urine bag again after my next ceCT scan."

Conclusion: Most outpatients were willing to use urine bags after ceCT. Urine bags were used for an average of 9 h after ceCT, ensuring that a substantial amount of the administered contrast medium does not enter the sewage system.

Key points: Question It is not known whether there is enough willingness among patients to use urine bags after contrast-enhanced CT (ceCT) to reduce contrast material in the water supply. Findings Urine bags offer a viable option to reduce the environmental impact of contrast agents and are acceptable to most outpatients. Clinical relevance The majority of outpatients were willing to help reduce the environmental impact of contrast material by using urine bags after ceCT so that excreted contrast material does not enter the water supply.