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APHA Scientific Session and Event Listing

Jonathan Sunshine, PhD, Cristian Meghea, PhD, and Mythreyi Bhargavan, PhD. Research, American College of Radiology, 1891 Preston White Drive, Reston, VA 20191, 703-648-4923, cmeghea@acr.org

Objective: Health costs are again growing rapidly, and MedPAC has identified medical imaging as one of the most rapidly growing components within the total. We present a detailed portrait of medical imaging's growth, analyzing the growth in ways that help identify its causes and possible remedies.

Data and Methods: We analyze 1986 to 2004 data from Medicare's Physician-Supplier Procedure Summary (PSPS, formerly BMAD) file, measuring imaging in physician work relative value units (PWRVUs), a metric not distorted by shifts in settings or changes in payment rates. Medicare constitutes about 1/3 of U.S. imaging services, has a consistent data set and a stable population, and presumably is broadly representative of all U.S. imaging.

Results Imaging per beneficiary increased by more than 200%, from 0.9 PWRVUs in 1986 to 3.0 in 2004, compared to an approximately 10% increase that would be expected from the aging of the Medicare population. Per beneficiary imaging by cardiologist increased by 1650%, increasing from 5% of total imaging in 1986 to 26% in 2004. Per beneficiary imaging by radiologists increased by 150%, falling from 78% to 60% of total imaging. Per beneficiary imaging by all others increased by 170%, falling from 17% to 14% of total imaging. Cardiac imaging increased from 8% of total imaging to 28%. Despite Medicare's 1998 addition of coverage for screening mammography, mammography increased only from 4% to 5% of total imaging. Higher-tech, non-cardiac imaging remained fairly constant at 47-51%. Within cardiac imaging, all three major forms (coronary angiography, echocardiography, and cardiac nuclear medicine) increased by at least 500% per beneficiary. All three are now performed dominantly by cardiologists. Cardiac nuclear medicine was initially performed 67% by radiologists and 13% by cardiologists, but cardiologists increased their per-beneficiary volume by over 5000% and now provide 66% of this imaging.

Conclusions: Cardiac imaging in particular, not high-tech imaging in general, had the highest growth rate, with all three of its major components showing extraordinary growth. Imaging—including that performed by radiologists—is almost always ordered by the treating physician. Thus, our findings on percentage shares of imaging and on growth rates support the cross-sectional, individual-physician-level literature that finds non-radiologists who do their own imaging (“self-referrers”)—and hence obtain the revenues from imaging—order 2-4 times as much imaging as colleagues in the same specialty seeing patients with the same problems, but who send their patients to radiologists for imaging.

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