Purpose: To evaluate cardiac nuclear medicine practice patterns in different physician specialty groups to better understand a recent rapid increase in utilization of radionuclide myocardial perfusion imaging (MPI) and certain supplementary examinations.
Materials and methods: National Medicare Part B databases from 1996 and 1998 were used to evaluate utilization of four primary procedure codes for radionuclide MPI and two supplementary codes (add-on left ventricular wall motion or left ventricular ejection fraction). Utilization rates were calculated for cardiologists, radiologists, and other physicians. Other cardiac imaging for which radionuclide imaging might be substituted was similarly studied.
Results: Overall utilization rate of radionuclide MPI per 100,000 Medicare beneficiaries increased 19.1%, from 4,046 in 1996 to 4,820 in 1998 (P <.001). However, for cardiologists the rate increased from 1,771 to 2,413 (36.3%), whereas for radiologists it increased from 1,958 to 2,031 (3.7%) (P <.001 for both changes). Overall utilization rate of add-on codes increased 264% from 1,006 to 3,657 (P <.001). By 1998, the ratio of these add-on examinations to primary MPI was 0.94 among cardiologists compared with 0.53 among radiologists (relative risk, 1.77; 95% CI: 1.76, 1.78). Cardiologist-performed stress echocardiography and cardiac catheterization and coronary angiography increased by 24.2% and 8.7%, respectively.
Conclusion: Growth in utilization of radionuclide MPI between 1996 and 1998 was almost 10 times higher among cardiologists than radiologists. Utilization of the two add-on codes increased even more dramatically. The greater use of MPI is not a substitute for other cardiac imaging.