Researchers have pitted PET and SPECT against each other yet again, and PET was crowned the victor.

More specifically, flurpiridaz F 18, Lantheus’ investigational PET agent for myocardial perfusion imaging (MPI), was found superior to SPECT for evaluating patients with coronary artery disease (CAD) during exercise stress testing.

PET MPI is usually used in combination with pharmacological stress testing because of the short half lives of the radiotracers that are currently available, including 13N-ammonia and Rubidium-82 chloride. Conducting PET exams with exercise stress helps clinicians gather important additional clinical information.
“We believe improved diagnostic accuracy, coupled with reduced radiation exposure and potential for quantification of coronary flow reserve, provide great promise for flurpiridaz F 18 to become the diagnostic imaging agent of choice for evaluating coronary artery disease,” Dr. Cesare Orlandi, chief medical officer of Lantheus Medical Imaging, said in a statement.

A team of researchers led by Dr. Rob Beanlands of the University of Ottawa Heart Institute conducted a multi-center international Phase 3 study. They enrolled about 800 patients with known or suspected CAD who were scheduled for coronary angiography and conventional SPECT.

Among those patients, 221 with known or suspected CAD underwent exercise stress flurpiridaz F 18 PET and SPECT imaging and coronary angiography.

They found that flurpiridaz F 18 PET imaging has greater sensitivity than SPECT imaging, but lower specificity. In addition, a statistically higher percentage of flurpiridaz F 18 PET images were rated as either excellent or good quality compared to the SPECT images.

This is not the first time that flurpiridaz F 18 has shown promise. In a previous study presented at the American College of Cardiology’s annual scientific session in 2016, it was found to be superior to MPI with SPECT for assessing CAD in obese patients.

“SPECT image quality and accuracy decreases as BMI increases, due to a number of factors including more scatter, more attenuation, and lower counts,” Dr. Timothy Bateman, cardiologist at Mid America Heart Institute and the presenter of the study, told HCB News at the time. “PET instrumentation reduces scatter and corrects for attenuation. PET quality is preserved as BMI increases, especially with F 18 tracers.”

This new research will be presented by Beanlands at the 21st Annual Scientific Session of the American Society of Nuclear Cardiology in Boca Raton, Florida.

Going forward, Lantheus plans to start the second of two Phase 3 trials for flurpiridaz F 18 PET imaging with a revised protocol that’s under an FDA-approved Special Protocol Assessment. The company is also in active discussions with potential partners that can help them further develop, manufacture, and commercialize this agent.

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