Combined CT and PET scanning improves cardiac risk prediction
Scientists have developed a new imaging technique that could help doctors to predict a patient’s risk of having a heart attack.
The British Heart Foundation (BHF) funded project, a collaboration between scientists from the Universities of Cambridge (Cambridge, UK) and Edinburgh (Edinburgh, UK), is the first to demonstrate the potential of combined PET and CT imaging to highlight the disease processes causing heart attacks directly within the coronary arteries.
The project involved imaging over 100 people with a CT calcium scan to measure the amount of calcified or hardened plaques in their coronary arteries. This is a standard test, which is commonly used to predict heart attack risk but cannot distinguish calcium that has been there for some time from calcium that is actively building up.
The patients were also injected with two contrast agents that show up on PET imaging scans. One of these tracers, 18F-sodium fluoride (18F-NaF), is a molecule taken up by cells in which active calcification is occurring. The 18F-NaF can then be visualized and quantified during a PET scan.
The researchers wanted to see if they could identify patients with active, ongoing calcification because these patients may be at higher risk of heart attack than patients in whom the calcium developed a long time ago. The results showed that increased 18F-NaF activity could be observed in specific coronary artery plaques in patients who had many other high-risk markers of cardiovascular disease.
“Our results show, for the first time, that certain areas of atherosclerosis within the coronary arteries, previously thought to be inert, are actually highly active and have the potential to cause heart attack. Once identified, they might be targeted with drug therapy more effectively. Additionally, we might be able to improve our ability to predict an individual person’s future risk of heart attack using this fairly straightforward imaging test in selected people,” said Dr. James Rudd, a senior lecturer at Cambridge University’s Department of Medicine.
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-- by Dave Wilson, Senior Editor, Vision Systems Design