Image-interpretation market scoreboard: Radiologists 72%, others 28%

Radiologists interpret almost all imaging studies generated in hospital settings for indications other than cardiac concerns. For those, cardiologists dominate the market, reading more studies than radiologists across all modalities except cardiac CT.

Researchers with the Harvey L. Neiman Health Policy Institute made the findings upon analyzing all diagnostic imaging claims for fee-for-service Medicare beneficiaries in 2022. JACR published the study report June 28 [1].

To perform the analysis, Eric Christensen, PhD, and colleagues aggregated claims into 52 specialty groups using Medicare specialty codes. They computed market share for each specialty group by modality, body region and place of service.

Overall, the researchers found, radiologists interpreted 72.1% of all diagnostic imaging claims for Medicare fee-for-service beneficiaries in 2022.

The rest, just under 28%, were submitted by clinicians in other specialties.

Concentrating on cardiac imaging, Christensen and colleagues found radiologists’ market share was 67.6% of cardiac CT, 42.2% of cardiac MRI, 11.8% of cardiac nuclear medicine and 0.4% of cardiac ultrasound.

Office-acquired imaging a segment of its own

The team also found radiologists interpreted 96.5% of hospital-based, noncardiac imaging exams in the study year. The hospital-based data included inpatient, outpatient and emergency imaging.

Sorted by modality, radiologists handled these reads for 99.5% of noncardiac CTs, 99.4% of noncardiac MRIs, 98.9% of noncardiac nuclear medicine studies, 97.9% of X-rays and 79.3% of noncardiac ultrasounds.

Meanwhile, for imaging acquired in office settings—in which many patient-facing physicians have access to in-house X-ray and ultrasound equipment related to their specialties—radiologists were outpaced in both those modalities, reading less than half of X-rays (43.1%) and less than a third of noncardiac ultrasounds (29.2%).

However, even in the office setting, radiologists interpreted a majority of noncardiac advanced imaging (84.4% of CT studies, 78.7% of MRI studies and 85.4% of nuc-med exams).

In their discussion, Christensen and co-authors comment that “various factors likely contribute to nonradiologist imaging, including whether in-house imaging by nonradiology practices is financially viable through self-referral, the degree to which hospitals centralize their imaging practice in radiology departments and the capability of modalities to limit imaging to specific organs.”

Stark Law ‘ineffective’

In a news release posted by the Neiman Institute, co-author Jeffrey Newhouse, MD, surmises that more nonradiologists capture market share with 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.”

This is rarely the case with advanced imaging, which involves much higher capital and operational costs, Newhouse adds, “making the economics impractical for most practices.”

Christensen, who serves the Neiman Institute as director of research, offers additional context.

“There are economic benefits to nonradiologists that likely contribute to their majority market share of X-ray and ultrasound imaging,” he says. “These providers have financial incentives for self-referral of imaging.”

More from Christensen:

“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. The literature shows that even after the passage of the Stark Law, self-referring nonradiologists ordered 1.2 to 6.4 times more imaging studies than those who do not self refer.”