Non-Invasive Molecular Imaging Predicts Heart Disease

Non-invasive myocardial perfusion imaging with PET scanning, followed by measurements of coronary flow reserve, can detect heart disease inside the coronary arteries, researchers said this week in two presentations at the Society of Nuclear Medicine’s 2012 Annual Meeting in Miami Beach, Fla.

In both studies, researchers from University Hospital Zurich, in Zurich, Switzerland, evaluated myocardial perfusion imaging, also known as a stress test, conducted with PET scanning, and measured coronary flow reserve (CFR). The researchers were able to measure the CFR because of the molecular imaging technique, which uses injected imaging probes that emit signals picked up by the specialized scanner. In both presented studies, the imaging was performed with ether Rb-82 or N-13-ammonia as an imaging biomarker to evaluate quantitative CFR.

In the first study of 73 subjects, the researchers measured the CFR and calculated the precise dilation of blood vessels at both rest and while under stress. They then compared their predictions with that of angiography. The researchers found significant improvements across five different reference points, including sensitivity, positive predictive value, and accuracy of myocardial perfusion imaging compared to imaging studies without CFR measurements.

In the second study, the researchers measured the CFR of 704 patients to see if age was always a risk factor for arterial disease. The results showed that age was not necessarily a risk factor, as originally believed.

“The quantification of CFR with molecular imaging provides a substantial advantage for unmasking coronary artery disease, even in patients who would otherwise be considered healthy with normal myocardial perfusion imaging,” said Michael Fiecher, MD, lead investigator of one of the studies.

Philipp Kaufman, MD, the other study’s lead author added, “Although different studies revealed a prognostic value of CFR, this study is the first that systematically assessed the diagnostic value of CFR against invasive coronary angiography as a standard of reference for detection of coronary artery disease.”