Comparative increases in utilization rates of ultrasound examinations among radiologists, cardiologists, and other physicians from 1993 to 2001

Abstract

Purpose: To ascertain changes in the utilization rates of diagnostic ultrasound among radiologists, cardiologists, and other physicians in recent years.

Methods and materials: The nationwide Medicare Part B databases for 1993 and 2001 were searched in all ultrasound Current Procedural Terminology 4 codes, except for ophthalmic ultrasound and supervision and interpretation codes. Ultrasound examinations were categorized as general, vascular, breast, obstetric (very low in the Medicare population), and echocardiography. Using the Medicare physician specialty codes, utilization rates per thousand Medicare beneficiaries per year were calculated for radiologists, cardiologists, and other physicians for all codes in the five aforementioned categories.

Results: Radiologists performed 24% of all ultrasound examinations in 2001. The overall utilization rate of ultrasound examinations among radiologists increased from 132.9 per thousand Medicare beneficiaries in 1993 to 166.3 in 2001, a 25% increase. Among cardiologists, the rate increased from 190.3 in 1993 to 356.1 in 2001, an 87% increase. The vast bulk of these examinations were echocardiograms, but cardiologists also had some involvement in vascular ultrasound. Among other physicians, the rate increased from 116.9 in 1993 to 167.0 in 2001, a 43% increase. The areas of greatest involvement by these other physicians were echocardiography, vascular ultrasound, and general ultrasound. Of the five ultrasound categories, echocardiography had by far the highest volume.

Conclusion: Nonradiologist physicians utilize ultrasound at much higher rates than radiologists, primarily reflecting the influence of echocardiography. Between 1993 and 2001, the ultrasound utilization rate grew over 3 times as rapidly among cardiologists as among radiologists; the rate among other physicians grew almost twice as rapidly as it did among radiologists. This raises the concern that self-referral may be leading to higher utilization and costs.