Comparative Trends in Utilization of MRI and Ultrasound to Evaluate Nonspine Joint Disease 2003 to 2015.

PURPOSE: MRI and ultrasound (US) are effective diagnostic tools to evaluate extremities. In this study, we analyze utilization trends in musculoskeletal (MSK) US and MRI from 2003 to 2015 within the Medicare population.

METHODS: Our data sources were the Medicare Part B Physician/Supplier Procedure Summary Master Files for 2003 to 2015. They cover all Medicare fee-for-service enrollees (37.5 million in 2015). Current Procedural Terminology codes for nonvascular, nonspine joint MRI and extremity US were selected and volumes within these codes were determined. Medicare's physician specialty codes were used to identify provider specialty. We accounted for the 2011 code change that created both complete and limited US examinations.

RESULTS: Total Medicare joint MRI volume increased from 738,509 in 2003 to 1,131,503 in 2015 (+53%), although there was little change after 2007. Radiologist MRI share in 2015 was 93%, followed by orthopedic surgeons at 5%. Total MSK US volume grew from 96,235 in 2003 to 429,695 in 2015 (+347%). Radiologists' market share of US decreased from 65% in 2003 to 37% in 2015, with nonradiologists now representing a majority of ultrasound examinations. Multiple nonradiology subspecialties also exceed radiology in volume of complete ultrasounds.

CONCLUSION: The potential negative impact of MSK US on MSK MRI volume is likely overestimated because MRI volume has remained stable. MSK ultrasound is increasingly utilized outside radiology. If radiologists want to maintain their market share as MSK imaging leaders, more emphasis should be placed on increasing their involvement and expertise in MSK US.