Multiple testing, cumulative radiation dose, and clinical indications in patients undergoing myocardial perfusion imaging.

Abstract

Myocardial perfusion imaging (MPI) is the single medical test with the highest radiation burden to the US population. Although many patients undergoing MPI receive repeat MPI testing, or additional procedures involving ionizing radiation, no data are available characterizing their total longitudinal radiation burden and relating radiation burden with reasons for testing. To characterize procedure counts, cumulative estimated effective doses of radiation, and clinical indications for patients undergoing MPI. A retrospective cohort study of 1097 consecutive patients undergoing index MPI during the first 100 days of 2006 (January 1-April 10) at Columbia University Medical Center, New York, New York, that evaluated all preceding medical imaging procedures involving ionizing radiation undergone beginning October 1988, and all subsequent procedures through June 2008, at the center. Cumulative estimated effective dose of radiation, number of procedures involving radiation, and indications for testing. Patients underwent a median of 15 (interquartile range [IQR], 6-32; mean, 23.9) procedures involving radiation exposure; of which 4 (IQR, 2-8; mean, 6.5) were high-dose procedures (≥3 mSv; ie, 1 year's background radiation), including 1 (IQR, 1-2; mean, 1.8) MPI study per patient. A total of 344 patients (31.4%) received cumulative estimated effective dose from all medical sources of more than 100 mSv. Multiple MPIs were performed in 424 patients (38.6%), for whom cumulative estimated effective dose was 121 mSv (IQR, 81-189; mean, 149 mSv). Men and white patients had higher cumulative estimated effective doses. More than 80% of initial and 90% of repeat MPI examinations were performed in patients with known cardiac disease or symptoms consistent with it. In this institution, multiple testing with MPI was common and in many patients associated with high cumulative estimated doses of radiation.