Heart researchers compare types of scans to determine which is most effective in detecting coronary artery disease
By Jess C. Gomez
Patients who receive cardiac positron emission testing imaging instead of single-photon emission computed tomography scan experienced a significant increase in the detection of severe obstructive coronary artery disease, according to researchers at the Intermountain Medical Center Heart Institute in Salt Lake City.
Both positron emission testing and single-photon emission computed tomography scans are nuclear imaging techniques that provide metabolic and functional information on the heart. Positron emission testing scans provide better image resolution and quality but have not yet gotten widespread adaptation compared to single-photon emission computed tomography. The study is one of the largest of its kind involving positron-emission-testing patients.
For the study, researchers examined Intermountain Healthcare’s Enterprise Data Warehouse, one of the nation’s largest depositories of clinical data, and identified 3,394 patients who underwent a pharmacologic single-photon emission computed tomography from 2011 to 2012 and 7,478 patients who underwent positron emission testing in 2014 and 2015 at Intermountain Medical Center. The average age of the patients was 65 years, and 47 percent of patients were female.
“The benefit of the study is that it helps us better identify a patient’s risk for adverse events affecting the heart and their need for further care,” said Dr. David Min, a cardiologist specializing in cardiac imaging at the Intermountain Medical Center Heart Institute and lead author of the study.
Researchers looked at pharmacologic single-photon emission computed tomography so the comparison with positron emission testing scans was more accurate. Both scans involve injecting a small dose of radioactive chemical, called a radiotracer, into the vein of the arm. The tracer travels through the body and is absorbed by the organs doctors examine.
Key findings of the study are as follows:
—Using positron emission testing scans instead of single-photon emission computed tomography scans resulted in increased rates of diagnosis of severe obstructive coronary artery disease from 70 percent to 79 percent.
— Positron emission testing scans were associated with a lower incidence of invasive catheterization without identification of severe coronary artery disease (43 percent vs 55 percent).
—Overall, positron emission testing more successfully identified patients with severe obstructive coronary artery disease and need for revascularization. Compared to single-photon emission computed tomography, positron emission testing scans increased true positives and reduced false positives for severe coronary artery disease.
Results of the study were presented at the American College of Cardiology Scientific Session In March.
“Since Intermountain Medical Center made the switch from single-photon emission computed tomography to positron emission testing in 2013, we thought it would be valuable to look at the differences in clinical outcomes since then,” said Dr. Kirk Knowlton, director of cardiovascular research at the Intermountain Medical Center Heart Institute. “In order to understand the differences between the two-year period of single-photon emission computed tomography utilization immediately before the positron emission testing program began and the two years after positron emission testing was fully implemented, we conducted a retrospective analysis of catheterization outcomes 60 days after heart patients received various treatments.”
“This study involves one of the largest number of positron emission testing patients studied to date,” Min added. “What we now know is that positron emission testing more successfully identifies patient who have high-grade coronary artery disease and may benefit from revascularization. Similarly, positron emission testing better identified patients who did not need an invasive procedure. This has broad implications as physicians consider what test best serves their individual patients and institutions consider the advantages and disadvantages of single-photon emission computed tomography and positron emission testing as well as downstream resource utilization.’”
