Who’s interpreting the imaging? Training makes a difference

With the growth of nonphysician providers in the health care workforce in recent years, the number of imaging studies being interpreted by nonphysicians has also grown—from just 0.01% in 1994 to 3.3% in 2020. That increase raises questions about the potentially unnecessary use of medical imaging and its implications for overall costs of care, physician-led team-based care and especially patient safety.

For a study published in the Journal of the American College of Radiology, researchers looked at repeat imaging rates for office-based imaging studies interpreted by nonphysician providers compared with radiologists.

Drawing on data from nearly 1.4 million office-based imaging claims for Medicare fee-for-service beneficiaries from 2013 to 2022, the researchers found a repeat-imaging rate of 12.5% within 90 days. Repeat-imaging rates varied by modality: 15.9% for radiography (XR), 4.6% for ultrasound (US) and 3.8% for magnetic resonance (MR).

But repeat-imaging rates, unadjusted for covariates, were significantly higher for nonphysician-interpreted studies than those interpreted by radiologists, and this was true for each modality: 20.4% versus 14.6% for XR, 11.6% versus 4.5% for US, and 8.8% versus 3.8% for MR.

When adjusted for covariates, the odds ratios for repeat imaging were also higher for nonphysician-interpreted imaging: 1.35 for XR, 2.41 for US and 2.56 for MR.

In addition, adjusted odds ratios for repeat imaging were higher for studies interpreted by nonphysician providers (NPPs) in all imaging families—the combinations of anatomic region and modality—except knee radiography. They were lowest for shoulder XR, at 1.39, and highest for abdominal US, at 3.40.

"To our knowledge, no previous study has investigated the association of provider type on repeat imaging rates," wrote the study’s authors.

"Although the study does not inform what the right repeat-imaging rate is, to the degree that NPPs are associated with repeat imaging rates above the ideal rate, the findings of this study highlight an opportunity to improve the judicious use of imaging in this context," says the study.

The AMA is fighting scope creep, defending the practice of medicine against scope of practice expansions that threaten patient safety and undermine physician-led, team-based care.

There’s no substitute for training

"The reason a study like this is important is that we want to make sure that the people interpreting the imaging are providing useful information," said Bonnie L. Litvack, MD, who chairs the American College of Radiology (ACR) State Government Relations Committee and is a former president of the Medical Society of the State of New York. Dr. Litvack is not an author of the Journal of the American College of Radiology study.

"Radiologists in general go through about 20,000 hours of training," Dr. Litvack said. "That includes medical school, a one-year internship, four years of residency and then, often, a fellowship. So there are many, many hours that are put into learning what the different modalities are and how to interpret them."

For comparison, physician assistants get only about 2,000 hours of supervised clinical practice in their master’s level training. Furthermore, physician assistants have no residency-training requirement. Check out more of the key differences between physicians and nonphysicians.

"Then, of course, we have a governing body, the ACR, that has our practice parameters and technical standards, which help make sure we're all on the same page and providing quality studies on both the technical side and the interpretation side," she said. "If people outside of that are doing interpretations, it's important to look at whether those interpretations are accurate, whether they're leading to diagnoses that are helping patients and whether you're even able to make diagnoses off of them."

The ACR provides state-level tracking of scope of practice bills that could significantly affect patient care and the integrity of medical imaging.

As always, patients matter most

"Our nonphysician providers are really important parts of our team, and I want to make clear this isn't a physician-versus-nonphysician issue," Dr. Litvack said. "It's really important that we practice health care in teams. That’s what's best for the patient. So we need to look at these things to figure out where there are gaps in training or knowledge."

There are also pressing issues of cost—nearly 10% of health care dollars in the U.S. are spent on imaging, she noted—and safety.

"Patient safety trumps everything," she said.

Image Wisely is a joint initiative of the ACR, the Radiological Society of North America, the American Society of Radiologic Technologists and the American Association of Physicists in Medicine that provides information to the medical community to promote safety in medical imaging.

"This falls squarely in the realm of patient safety because if you're repeating these images, there can be issues with excess ionizing radiation," she said.

The authors noted several limitations to their study. These include that it shows the repeat-imaging rates of Medicare fee-for-service beneficiaries only and may not be reflective of patients with Medicare Advantage, Medicaid or commercial insurance.

Learn more with the AMA about great resources that set the record straight for policymakers on scope of practice. The AMA is one of the only national organizations that has created hundreds of advocacy tools for medicine to use when fighting scope creep.