Excess Greenhouse Gas Emissions Associated With Inappropriate Medical Imaging in the US Medicare Part B Population From 2017 to 2021.

INTRODUCTION

Medical imaging is a source of greenhouse gas emissions, and inappropriate use results in low-value, excess imaging. The environmental impact of low-value imaging has not been quantified.

OBJECTIVE

This study seeks to estimate excess greenhouse gas (GHG) emissions associated with inappropriate imaging in metric kilotons (kT) of carbon dioxide equivalents (CO2e) from the Medicare Part B population from 2017 to 2021.

MATERIALS AND METHODS

Using the Harvey L. Neiman Health Policy Institute 2017 to 2021 data on trends in imaging utilization for Medicare Fee-for-Service Beneficiaries and the 2014 RAND Corporation report on Medicare Imaging Demonstration, low-end and high-end estimates of average yearly GHG emissions from inappropriate examinations in Medicare Part B population were modeled for the four most-common imaging modalities (MRI, CT, radiography, and ultrasound) from the estimated number of inappropriate examinations per year and GHG emissions per modality.

RESULTS

Of all imaging, 4% to 26% is estimated as inappropriate. Total inappropriate Medicare imaging examinations were estimated to have produced an average of 3.55 to 129.2 kT CO2e per year during the entire 5-year period, with MRI and CT accounting for the greatest proportion (0.621-33.8 kT and 1.24-64.8 kT, respectively); 3.55 to 129.2 kT CO2e approximates to the GHG produced by the yearly electricity of a town of 2,000 to 72,000 people, respectively.

CONCLUSION

Our results demonstrate that substantial excess GHG emissions arise from inappropriate imaging, particularly MRI and CT. These data support the need to reduce low-value imaging and adherence to appropriate use criteria.