Recent Trends in Utilization Rates of Abdominal Imaging: The Relative Roles of Radiologists and Nonradiologist Physicians

Abstract

To study recent trends in the utilization of abdominal imaging in the Medicare population. The Medicare Part B databases for 1996 through 2005 were reviewed, and all Current Procedural Terminology, 4th ed, codes pertaining to noninvasive imaging of the abdomen and pelvis were identified. The codes were grouped into 6 categories: (1) computed tomography (CT) and CT angiography, (2) magnetic resonance (MR) and MR angiography, (3) ultrasound, (4) radionuclide imaging, (5) plain radiography, and (6) gastrointestinal fluoroscopy. Global and professional-component claims from all places of service were tabulated for the 6 categories. Utilization rates per 1,000 Medicare fee-for-service beneficiaries were calculated. Medicare physician specialty codes were used to identify examinations by radiologists and nonradiologist physicians. Overall utilization trends were studied, as were those among radiologists and nonradiologists. In 1996, an overall total of 451.8 abdominal imaging examinations were performed per 1,000 Medicare beneficiaries, increasing to 564.5 in 2005 (+25%). The greatest growth was seen in computed tomography and computed tomographic angiography, which rose from 99.4 examinations in 1996 to 239.3 in 2005 (+141%). Ultrasound increased from 126.6 examinations in 1996 to 142.2 in 2005 (+12%). Plain abdominal radiographic examinations decreased from 144.1 to 125.4 (-13%), and gastrointestinal fluoroscopic examinations decreased from 67.3 to 34.8 (-48%). The utilization of MR and MR angiography and radionuclide imaging was far lower. Radiologists' market share of abdominal imaging was 88% in 1996 and 90% in 2005. Between 1996 and 2005, the utilization rate among radiologists increased by 29%, compared with 11% among nonradiologist physicians. In recent years, the increase in the utilization rate of abdominal imaging among the Medicare population was relatively moderate (25% over 9 years). There was a substantial increase in the use of computed tomography and computed tomographic angiography and a smaller increase in the use of ultrasound. The use of plain radiography and gastrointestinal fluoroscopy declined. Radiologists strongly predominate in abdominal imaging, and this may be one reason why growth has been modest.