A better tracer

The novel imaging technique developed by the University of Edinburgh takes yet another approach toward heart attack prediction by visualizing unstable plaque with high levels of microcalcification.


A key innovation of the study was using NaF (sodium fluoride) a tracer commonly used to image bone, instead of FDG (fluorodeoxyglucose) which had been the gold standard for plaque imaging up until now.

The study, which used both FDG and NaF to image 40 patients with acute myocardial infarction and 40 with stable angina, showed that NaF may, indeed, be better at showing these high-risk blockages.

Ruptured plaque of heart attack patients absorbed 34 percent more NaF than nonculprit plaques. Additionally, nearly all of the patients (93 percent) had increased NaF in the ruptured part of their heart. This distinction was not apparent between culprit and nonculprit plaques when FDG was used, however.

NaF works by being drawn to active microcalficiation in the plaque. When the molecule is absorbed by ruptured or rupture-prone plaque, it lights up the culprit site in heart scans.

But microcalcification isn’t just an indicator of risk — it also provides additional information to doctors because it indicates whether the plaque is still metabolically active or dormant.

“The main difference between this method and others that are available or under investigation now is that sodium fluoride PET/CT indicates metabolic activity — it describes the dynamics of the plaque rather than a snapshot of its chemical composition,” said Dr. Reka Haraszti from the University of Massachusetts Medical School in Worcester.

In other words, researchers hope that this information will go beyond just identifying plaque as high-risk by predicting with greater accuracy whether that plaque is at risk for rupturing in the near future.

"With other imaging techniques, we can tell the risk is higher, but we can’t guarantee if that plaque will rupture soon," said Haraszti.

The test also uses equipment readily available in most hospitals, whereas near infrared spectroscopy would require purchasing new technology.

New research ahead

Experts agree more research needs to be done to explore the methods and techniques that are in the works now before declaring one of them the gold standard.

“I think that it’s always good to look into more techniques, I think complementary information could be useful especially since different techniques will tell us different information and more information might make it easier to help predict heart attacks,” said Haraszti.

More Industry Headlines