Implementation of Ultra-Low-Dose CT for Renal Stone Surveillance Was Associated With Reduced Ultrasound and...

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.

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.

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.

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.