The number of private-practice radiologists increased in 2007. Source: StatSimple

The most common modalities owned by private-practice radiologists were MR and CT systems, according to a 2007 survey published in the September issue of the Journal of the American College of Radiology.

The 2007 Survey of Radiologists: Practice Characteristics, Ownership, and Affiliation With Imaging Centers, by James W. Moser, PhD, interpreted data from survey responses by 601 currently practicing radiologists.

The prevalence of MR and CT scanners may be attributed to the fact that they have the highest rate of return on investment compared with other imaging technologies and are thus the most frequently used modalities in the non-hospital setting, according to Moser.

The most frequently reported subspecialties in radiology were interventional at nearly 20 percent, and neuroradiology at approximately 16 percent. Mean practice size was reported at 20 full-time radiologists with each radiologist performing 14,000 imaging studies annually.

The survey results also revealed a shift in where radiologists work. Whereas 40 percent worked in private, radiology-only practices in 2003, slightly more than half did so in 2007, accompanied mainly by a reduction of comparable magnitude in the percentage working in multispecialty practices. Sole practitioners, as well as locum tenens, government and hospital radiologists experienced share reductions over the four-year period while academic practice affiliation rose slightly.

Regarding affiliation with imaging centers, nearly half of the respondents indicated they had equity interest in the centers.

Moser wrote that the trend toward larger practice sizes could reflect increasing pressure on radiology practices to become more efficient by scaling up to gain more market power with payors and hospitals in light of decreasing public and private payor reimbursements. It is also likely due in part to the proliferation and diffusion of teleradiology and the centralized transmission of digital images. Rural sites now need only one on-site radiologist for contrast procedures, and the remainder of images can be sent to a metropolitan center or other location for interpretation, he noted.

Of particular interest is that 42 percent of practice owners also were contractors of imaging centers. These could be contracts with centers other than ones owned by such individuals, or contracts with imaging centers by radiologists who own the practices in which they work but do not own imaging centers. Moser wrote that the interface between practice ownership and affiliation with imaging centers is not a straightforward one.

Survey timing and resource constraints limited the ability to provide meaningful statistics for detailed breakouts. Statistics drawn from the 2007 survey of radiologists may have inaccuracies from several sources: sampling variability, non-response bias, and incorrect or illogical responses, the author noted.