The ratings agency contends RadNet is constrained by its geographic concentration in 11 states and high fixed costs, including sizable interest expenses. 

Though these treatments are typically done with assistance from real-time fluoroscopy, there is ample evidence nuclear imaging may offer more benefits.

Last month saw the release of research showing a small but nontrivial number of physicians quit the job soon after completing residency training. Now comes a separate study suggesting the reasons for the phenomenon are often deep, diffuse and knotty—and thus difficult to address in a strictly programmatic way.