SNMMI: Exercise FDG-PET Outdoes Stress MPI in Detecting Ischemia


In a recent study, presented at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) annual meeting, it was found that Exercise FDG-PET considerably outdid SPECT myocardial perfusion imaging (MPI) in identifying  ischemia in patients with single-vessel disease.

For patients with stenosis higher than 50%, exercise FDG-PET pulled out an impressive sensitivity rating at 96%; as opposed to 56% for stress technetium-99m (Tc-99m) tetrofosmin SPECT MPI. FDG-PET also demonstrated a 76% precision rate in this sitting, whereas the stress MPI only attained a precision rate of 62%.

In addition, for patients with stenosis higher than 70%, the team found that both procedures were evenly matched.

“The findings could lead to the use of nuclear medicine in preventive cardiology, given FDG-PET's apparent ability to detect ischemia at a very early stage before changes become apparent with angiography,” said lead researcher from the department of nuclear medicine at the Post Graduate Institute of Medical Education and Research (PGIMER) in Chandigarh, India, Dr. Arun Sasikumar.

For the promising study, 45 patients with clinical suspicion of coronary artery disease and no history of myocardial infarction were enrolled.

Of the 45 patients, 37 were men, while the remaining eight were women, with an average age of 51 and a total age range from 27 to 71 years.

Every patient was subjected to a stress SPECT MPI using a treadmill in one day. Exercise FDG-PET was administered after inserting 5 mCi of FDG on a different day.

The researchers contained physiologic myocardial FDG intake in patients by having them eat a high-fat, high-protein, low-carbohydrate meal preceding FDG-PET. Each patient was also subjected to a coronary angiography within 30 days of the other scans to offer a basis for evaluation between SPECT MPI and FDG-PET results.

Twenty-seven patients had irregular coronary angiography that displayed at least one coronary artery with stenosis higher than 50%. Of the 27 patients, 17 had single-vessel disease, five had double-vessel disease, and five had triple-vessel disease.

For the 17 patients with single-vessel disease, FDG-PET notably outdid SPECT MPI (p = 0.0005). For patients who had stenosis higher than 50%, exercise FDG-PET had sensitivity of 96%, whereas stress SPECT MPI had 56%. Accuracy was 76% for FDG-PET, as opposed to SPECT MPI with 62%, proving that FDG-PET detects earlier stages of disease, according to the study.

For patients with multivessel disease, exercise FDG-PET did just as well as stress SPECT MPI (for double-vessel disease, p = 0.683; for triple-vessel disease, p = 1.0).

Additionally, exercise FDG-PET was also much better than stress SPECT MPI in the left anterior descending and left circumflex arteries with equally fine performance in the right coronary artery. In patients with stenosis higher than 70%, both procedures were evenly matched (p = 0.61).

“Given exercise FDG-PET's prowess, physicians could prescribe medications that can halt disease progression and prevent a potentially devastating cardiac event, such as a heart attack or sudden cardiac death,” Sasikumar and colleagues concluded.

Exercise FDG-PET could also be useful for preliminary coronary artery disease screening to assist physicians in assessing a patient’s cardiac risk and manage treatment.