Almost a third of imaging exam interpretations are performed by nonradiologists, according to a Harvey L. Neiman Health Policy Institute (HPI) study.
A team led by Eric Christensen, PhD, research director at the Neiman Institute, reported that radiologists interpreted 72.1% of all imaging studies for Medicare fee-for-service beneficiaries in 2022, but that the remaining 27.9% were performed by other types of clinicians, particularly cardiologists. The results were published on June 28 in the Journal of the American College of Radiology.
"Cardiologists interpret most cardiac imaging, and a greater share [of it] than radiologists for all modalities except cardiac CT," Christensen said in a statement released by HPI. "Cardiology is the only non-radiology specialty that interprets a large percentage of advanced imaging -- CT, MR, and NM -- but only cardiac [exams]."
The team conducted a study that included data from 123 million 2022 Medicare Part B imaging claims. Of these, 88.5 million (72.1%) were interpreted by radiologists. This overall percentage varied by modality, the group reported:
- 97.3% for CT
- 91% for MRI
- 76.6% for digital x-ray
- 0.9% for nuclear medicine
- 33.9% for ultrasound
Radiologists performed a lower percentage of cardiac exams compared to noncardiac ones. But the investigators also noted that radiologists interpreted nearly all outpatient hospital, inpatient, and emergency department exams compared to those conducted in an office setting.
| Market share of radiologist imaging study interpretations by modality, body area, and place of service | ||||
|---|---|---|---|---|
| Modality | Cardiac studies | Noncardiac studies | Hospital setting | Office setting |
| CT | 67.6% | 97.6% | 99.5% | 84.4% |
| MRI | 42.2% | 91.4% | 99.4% | 78.7% |
| Nuclear medicine | 11.8% | 95.6% | 98.9% | 85.4% |
| Ultrasound | 0.4% | 53% | 79.3% | 29.2% |
| X-ray | -- | -- | 97.9% | 43.1% |
"Non-radiologists have likely been more successful with capturing market share with [digital x-ray] and ultrasound than with advanced modalities because imaging volume from their practice's patients alone may be sufficient for a positive return on investment for providing these services," coauthor Jeffrey Newhouse, MD, of the Columbia University Medical Center in New York City said in the HPI statement. "However, advanced imaging involves substantially higher capital and operational costs, making the economics impractical for most [non-radiology] practices."
The study findings shed light on the impact of the Stark Law, Christensen said.
"The Stark Law, which was designed in part to prohibit self-referral of imaging to facilities in which the referring physician had a financial interest, has largely been ineffective," he noted. "The literature shows that even after the passage of the Stark Law, self-referring non-radiologists ordered 1.2 to 6.4 times more imaging studies than those who do not self-refer."
The complete study can be found here.
