Medicare Policy Initiatives and the Relative Utilization of "Double-Scan" CT

Purpose: Commonly called "double scans" by the media, combined pre- and postcontrast thoracic and abdominal CT examinations have been the focus of recent CMS policy initiatives. The aim of this study was to examine trends in the relative utilization of double-scan CT before and after 2006 legislation mandating relevant Medicare reporting initiatives.

Methods: Medicare Physician Supplier Procedure Summary Master Files from 2001 through 2012 were used to identify claims for thoracic and abdominal CT examinations. Double-scan rates by billing physician specialty and place of service were analyzed over time. Rates of double-scan CT between radiologists and nonradiologists were compared using t tests.

Results: From 2001 to 2006, double-scan rates for thoracic and abdominal CT examinations declined by 1.7% and 7.5% for radiologists, respectively (from 6.0% to 5.9% and from 22.6% to 20.9%) but increased by 15.8% and 23.6% for nonradiologists (from 5.7% to 6.6% and from 28.8% to 35.6%). From 2006 through 2012, double-scan rates declined by 42.3% and 35.2% (from 5.9% to 3.4% and from 20.9% to 13.5%) for radiologists but only by 31.8% and 8.1% (from 6.6% to 4.5% and from 35.6% to 32.7%) for nonradiologists. Double-scan rates were significantly lower for radiologists than nonradiologists for all years for abdominal CT (P < .001) and for all years after 2006 legislation for thoracic CT (P < .05).

Conclusions: Reductions in thoracic and abdominal CT double-scan rates followed legislation mandating CMS initiatives designed to reduce costs and radiation. For nonradiologists, double-scan rates were consistently higher and declined more slowly than those for radiologists. Medicare policy initiatives directed toward imaging utilization seem to influence behavior differently for radiologists compared with nonradiologists.