Energy Conservation in MRI: Sequence Selection and Operational Strategies

The healthcare system accounts for approximately 9.8% of the United States' (U.S.) greenhouse gas emissions, much of which is due to imaging, particularly magnetic resonance imaging (MRI). This study investigates the components of MRI energy consumption and compares sequences that may be interchangeable in clinical practice. Although the greatest potential for decreasing energy expenditure lies in reduction of inappropriate imaging and optimizing energy consumption of idle MRI equipment, sequence substitution offers an underexplored solution that can potentially be implemented without changing practice patterns or capital expenditure.

MRI energy expenditure of one machine was monitored for one month. Energy measured in kilowatt-hour (kWh) was separated into usage by gradients and system electronics. Patient data was de-identified, aggregated by sequence, and analyzed.

87 patients underwent 790 sequence instances during the monitoring period. The cumulative energy consumption was 20,508.84 kWh, with 76.89% (15,769.11 kWh) attributed to gradient systems and 23.11% (4739.74 kWh) to system electronics. Significant differences between clinically similar sequences were identified, with energy-efficient alternatives demonstrating 20-49% reduction in per-sequence energy consumption.

There are significant differences in energy consumption between gradient and system electronics components of MRI systems, depending on running/idle status and sequence type. Several potential sequence substitutions provide comparable diagnostic information and reduce energy use. Therefore, clinical operations decisions and sequence selection can reduce the environmental impact of MRI services.