A new way of scanning the heart can identify those who may be at high risk of a heart attack, early tests suggest.
It can identify dangerous plaques in the arteries which nourish the heart. If a fatty plaque ruptures, it can lead to a clot, blocking the flow of blood.
Scientists at the University of Edinburgh said an effective tool for predicting a heart attack would make a "massive difference" to patients. Experts said it was an exciting start.
More than 100,000 people have a heart attack in the UK each year and disease of the arteries around the heart is the leading cause of death in the world.
The researchers used a radioactive tracer which can seek out active and dangerous plaques. This was combined with high resolution images of the heart and blood vessels.
The overall effect is a detailed picture of the heart with the danger zones clearly highlighted. The technology is already used to detect tumours in cancer patients.