When does a radiologist's recommendation for follow-up result in high-cost imaging?

To measure the proportion of high-cost imaging generated by a radiologist's recommendation and to identify the imaging findings resulting in follow-up.

This retrospective HIPAA-compliant study had institutional review board approval, with waiver of informed consent. A recommended examination was defined as one performed within a single episode of care (defined as fewer than 60 days after the initial imaging) following a radiologist's recommendation in a prior examination report. Chest and abdominal computed tomography (CT), brain and lumbar spine magnetic resonance (MR) imaging, and body positron emission tomography were included for analysis. From a database of all radiology examinations (approximately 200,000) at one institution over a 6-month period, a computerized search identified all high-cost examinations that were preceded by an examination containing a radiologist recommendation. Medical records were reviewed to verify accuracy of the recommending-recommended examination pairs and to determine the reason for the radiologist's recommendation. For proportions, 95% confidence intervals were calculated.

Overall, 1558 of 29,232 (5.3%) high-cost examinations followed a radiologist's recommendation. Chest CT was the high-cost examination most often resulting from a radiologist's recommendation (878 of 9331, 9.4%), followed by abdominal CT (390 of 10,258, 3.8%) and brain MR imaging (222 of 6436, 3.4%). The examination types with the highest numbers of follow-up examinations were chest radiography (n=431), chest CT (n=410), abdominal CT (n=214), and abdominal ultrasonography (n=120). The most common findings resulting in follow-up were pulmonary nodules or masses (559 of 1558, 35.9%), other pulmonary abnormalities (150 of 1558, 9.6%), adenopathy (103 of 1558, 6.6%), renal lesions (101 of 1558, 6.5%), and negative examination findings (101 of 1558, 6.5%).

Radiologists' recommendations account for only a small proportion of outpatient high-cost imaging examinations. Pulmonary nodule follow-up is the most common cause for radiologist-generated examinations.