Radiology practices grew in size throughout the 1990 to 2007 period with significant growth occurring in practices with 30 or more radiologists, according to a report in the July issue of the Journal of the American College of Radiology.
Mythreyi Bhargavan, PhD, from the department of radiology and radiological science at Johns Hopkins University in Baltimore, and Jonathan Sunshine, PhD, from the department of diagnostic radiology at Yale University in New Haven, Conn., extracted data from the American College of Radiology’s 1990, 1995, 2000 and 2003 surveys of U.S. radiologists and radiation oncologists. They compiled the 2007 survey of radiologist members to describe the changing distribution of radiologists by practice size over time.
The researchers found that the fraction of radiologists in small practices (one to four radiologists) decreased from 29 percent in 1990 to 22 percent in 2007. The fraction in medium-sized practices (five to 14 radiologists) decreased from 51 percent in 1990 to 38 percent in 2007, according to Bhargavan and Sunshine.
The investigators found that the fraction in practices with 15 to 29 radiologists increased from 14 percent in 1990 to 21 percent in 1995 and has since remained constant. However, they found that the fraction in practices with 30 or more radiologists grew from 5 percent in 1990 to 19 percent in 2007, but since 2000, growth among these practices has largely been limited to practices with 60 or more radiologists.
The median radiologist was in a seven-radiologist practice in 1990, but this size increased to 11 in 2000 and was the same in 2007. The size of a practice at the 90th percentile of radiologists increased from 22 in 1990 to 45 in 2007, according to the authors.
Based on their findings, Bhargavan and Sunshine concluded that in general, changes were more rapid in 1990 to 2000 than since that time, and the most conspicuous growth was in practices with 30 radiologists or more, which has almost quadrupled its share of radiologists. In contrast, the share of very small practices (one to four radiologists) declined relatively little, by only approximately one-fourth, according to the authors.