Office-Based Diagnostic Imaging Interpreted by Nonphysician Practitioners: Characteristics, Recent Trends, and State Variation.

Purpose: Diagnostic imaging interpretations by nonphysician practitioners (NPPs) are increasing. With hospital-based imaging overwhelmingly interpreted by radiologists, we studied office-based interpretations by NPPs by their physician employer specialty.

Methods: Linking Medicare claims and provider datasets, we identified imaging interpretation claims submitted by nurse practitioners and physician assistants (together NPPs) in office settings, mapping NPPs to physician employer specialties, and assessed NPP characteristics and practice patterns.

Results: Between 2013 and 2022, the share of office-based imaging interpretations by NPPs increased 9.0% annually (from 2.52% to 5.47%) overall and by the following modalities: radiography (8.9%; 4.30%-9.23%), ultrasound (9.4%; 0.52%-1.18%), CT (9.4%; 0.13%-0.28%), MR (9.9%, 0.19%-0.44%), and nuclear medicine (7.2%; 0.07%-0.12%). Just 5.55% of NPPs rendered interpretations. NPPs employed by primary care physicians (PCPs) and orthopedists interpreted the largest shares of NPP imaging (39.5% and 34.1%, respectively). By modality, the largest shares by employer specialties were PCPs and orthopedists for radiography (39.7%, 37.4%), PCPs and practices without physicians for ultrasound (44.7%, 12.7%), PCPs and otolaryngologists for CT (58.2%, 17.1%), orthopedists and PCPs for MR (60.3%, 24.0%), and PCPs and cardiologists for nuclear medicine (40.4%, 25.9%). Younger NPPs (<35 years) interpreted imaging more frequently than older counterparts (≥65) (odds ratio 1.42 [95% confidence interval: 1.37-1.48]) and male NPPs interpreted imaging more frequently than female NPPs (odds ratio 1.61 [95% confidence interval: 1.58-1.63]). Overall interpretation shares ranged from 13.16% in Alaska to 0.29% in Washington, DC.

Conclusion: In Medicare, the share of office-based imaging interpretations performed by NPPs is increasing, varying considerably by state. Interpretations are performed by relatively few NPPs, particularly those younger, male, and employed by PCPs and orthopedists.