The Radiology 100: Grows Upward

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The nation’s 100 largest private radiology practices bulk up, adding radiologists but shedding employees and imaging center assets as they grow

The nation’s largest radiology practices sought strength in numbers, sending the median practice size of the 100 largest private radiology practices soaring, from 41.7 in 2014 to 47 in 2015. Much of that growth occurred at the lofty heights of the Radiology 100 list, in practices of 65 or more full-time equivalent radiologists.

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Signs of a maturing radiology marketplace can be seen in the consolidation of radiology providers, the growth in hospital contracts among the largest practices and the loss of hospital contracts among the smallest practices. The bloom appears to be off imaging center asset ownership, as all practice size cohorts shed imaging centers.

Co-sponsored by accounting firm CliftonLarsonAllen and Radiology Business Journal, the eighth annual survey to rank the 100 largest private radiology practices was posted online at and publicized through email. We received 70 responses, not all of which ranked in the Radiology 100. Practices were ranked based on their number of full-time equivalent (FTE) radiologists. When two practices had the same number of radiologists, we ranked the practice with the greater number of FTE employees higher.

In an effort to make the list as accurate as possible, we reached out to known practices of size via email and telephone to collect the basic data points, including those illustrated in Figures 1–6. When we could not connect with a practice representative, we counted the number of radiologists on the practice’s web site; those practices are printed in italics because their radiologist counts are body counts, not FTE counts.

While the median size of the Radiology 100 took a five-FTE leap this year, most of the action was at the top of the list.  The median size of the smallest practice cohort ( < 35 FTE radiologists) increased by one, from 29 to 30 ( Figure 1). The 35 to 49 FTE radiologist cohort actually declined by one, from 41 to 40. The second-largest size cohort was flat at 56 FTEs, and the largest practice-size cohort jumped by more than three radiologists, from 82.9 to 86.

The composition of the list has changed significantly since we began tracking the nation’s largest private radiology practices. Back in 2008, our first annual survey ranked the nation’s 50 largest radiology practices—and included hospital-based practices. The largest practice on the list was Brigham & Women’s Department of Radiology, Boston, with 95 FTE radiologists, and the smallest, Windsong Radiology, Williamsville, NY, had 15 radiologists.

When we expanded the ranking to include the 100 largest private radiology practices in 2011, the largest practice, Radiology Associates of North Texas (RANT), had just formed a 122-radiology mega-practice from a merger of  three smaller practices and just 15 practices on the list had more than 65 radiologists. In 2015, practices of more than 65 radiologists numbered 20.

In the heights

RANT continues to dominate the list ( see Table) in size at a whopping 128 FTE radiologists, adding six FTE radiologists since last year. With no imaging centers and 25 hospital contracts, the practice is exclusively hospital based, employing just 50 employees and generating 2,197,152 reads.

University Radiology added 10 FTE radiologists for a total of 106 FTEs, leap-frogging from fifth on the list last year to become the second-largest practice in the U.S. The group had 61 FTE radiologists when it first appeared on the list at number 14 in 2009, with eight imaging centers and 300 FTE employees. It performed 1,242,000 studies.

Bucking the divestiture trend, the practice continues to grow its imaging center assets, adding one center last year for a total of 16. University Radiology employs 474 FTE employees.

Michigan-based Advanced Radiology Services, a veteran of the top five since we began conducting the survey, occupies the No. 3 spot on the list this year with a total of 106 FTE radiologists. A hospital-based practice, Advanced Radiology Services has no imaging centers, 113 FTE employees and serves 14 hospitals.

Southwest Diagnostic Imaging (SDI), Phoenix, Ariz., slipped from the third to the fourth position on the list, with 101 FTE radiologists, the same as last year, the same number of hospital clients, 15, and with roughly the same number of procedures: 1,821,680 versus 1,823,551 in