Implementation of Ultra-Low-Dose CT for Renal Stone Surveillance Was Associated With Reduced Ultrasound and Radiograph Use: A Multidisciplinary Quality Improvement Initiative.

OBJECTIVE: Renal stone surveillance often relies on ultrasound (US) and radiograph (KUB) due to concerns about CT radiation and cost, despite CT's superior accuracy. Limited awareness and accessibility of ultra-low-dose (ULD) CT contributes to underuse. We aimed to reduce US use for renal stone monitoring by 30% with KUB tracked secondarily without increasing Medicare-allowed amount through implementation of a ULD CT protocol. METHODS: Using the Six Sigma DMAIC framework, a multidisciplinary team analyzed baseline imaging patterns and identified key drivers of US/KUB overuse: radiation concerns and lack of awareness and accessibility. Interventions included incorporating a tin-filter ULD CT protocol and recommending CT for surveillance imaging. Imaging utilization and costs were monitored by three phases (baseline/implementation/sustained adoption. RESULTS: Implementation of the ULD CT protocol reduced mean radiation dose by 66% (from 5 mSv to 1.7 mSv) compared to standard low-dose noncontrast CT. When compared to the baseline, in the sustained-adoption phase, US utilization decreased from a median of 35 examinations per month (IQR 30-36) to 10 examinations per month (IQR 8.5-18), representing a 71.4%% reduction (p = 0.002), KUB reduced from median of 15.0 (IQR 9-19) to 4.0 (3-5.5) (p = 0.005), while ULD performed increased from median 0 (IQR 0-0) to 43.5 (IQR 32.5-58.5) (p<0.001). The Medicare global fee for combined US/KUB was $133.59 compared with $180.82 for ULD CT, an absolute difference of $47.23, not accounting for potential additional time and coordination associated with two radiology visits for US/KUB-based surveillance. CONCLUSION: Implementing ULD CT standardized renal stone surveillance, reduced US/KUB use, however had a modest increase in cost difference in Medicare-allowed amount. Findings support broader adoption of ULD CT and aligning with updated national guidelines.