New imaging technique spots early stages of dangerous artery deposits

13 Jul

Atherosclerosis – where fatty calcium deposits clog up arteries and reduce blood flow

and oxygen supply – can lead to heart attacks and strokes. Now, a team says it is possible to

identify the early stages of this process on a noninvasive imaging system thanks to an

inexpensive, repurposed radioactive agent.

atherosclerosis illustration
In some cases of atherosclerosis, pieces can break

off from the calcium deposits.

In Nature Communications, researchers from the universities of Cambridge and

Edinburgh in the UK, describe how they used a radioactive agent that was first developed in

the 1960s to detect bone cancer to highlight the build-up of unstable calcium deposits in

patients’ arteries.

Study leader Dr. Anthony Davenport, of the department of medicine at Cambridge,

says this “new emerging technique is the only imaging platform that can noninvasively detect

the early stages of calcification in unstable atherosclerosis.”

He and his colleagues expect the technique – which uses sodium fluoride tagged with a tiny

amount of radioactive tracer – will help diagnose atherosclerosis and develop new drugs to

treat it.

There are several ways atherosclerosis can be dangerous. One way is that the gradual

build-up of fatty deposits (known as “plaques”) gradually harden and narrow the artery wall,

eventually restricting blood flow and oxygen supply.

Not clear which patients will develop dangerous, unstable calcium deposits

Another way that atherosclerosis can be dangerous is that in some cases, pieces can break

off from the calcium deposits. If that happens in an artery that supplies the brain or the

heart, it can cause a blockage that results in stroke or heart attack.

While it is clear that atherosclerosis can lead to very serious disease, what is not so

clear is which people will develop the unstable plaques that allows pieces to break off – so

the earlier they can be identified, the better the chances that early treatment will save


For their study, the team injected patients with the radiotracer version of sodium

fluoride (18F-NaF).

Then, using a combination of imaging techniques (positron emission tomography

and computed tomography, or PET/CT), they tracked the tracer as it moved around

the body.

“Sodium fluoride is commonly found in toothpaste as it binds to calcium compounds in our

teeth’s enamel,” Dr. Davenport explains, “In a similar way, it also binds to unstable areas of calcification in

arteries and so we’re able to see, by measuring the levels of radioactivity, exactly where

the deposits are building up.”

Sodium fluoride tracer should ‘revolutionize’ detection of dangerous calcium


After undergoing the scans, the patients had surgery to remove the plaques in their

arteries. The researchers then examined them at a higher resolution using a laboratory

PET/CT scanner and an electron microscope.

This detailed examination confirmed that the 18F-NaF tracer builds up in areas of

active, unstable calcium deposits, and not in surrounding tissue.

Co-author, Dr. James Rudd, a cardiologist and researcher at Cambridge, says 18F-NaF is a

simple and inexpensive tracer that should “revolutionize” the ability of doctors to detect

dangerous calcium deposits in the arteries of the heart and brain. He concludes:

“This will allow us to use current treatments more effectively, by giving them

to those patients at highest risk. In addition, after further work, it may be possible to use

this technique to test how well new medicines perform at preventing the development of


Most of the funds for the study came from the Wellcome Trust, supplemented with

contributions from the British Heart Foundation, Cancer Research UK and the Cambridge NIHR

Biomedical Research Centre.

In February 2015, Medical News Today learned how researchers are working on a way

to get nanomedicines to treat atherosclerosis. Writing in

Science Translational Medicine, a Harvard-led team describes how they developed

nano-sized “drones” that deliver targeted drugs and repair arteries. The tiny particles were

small and sticky enough to push their way under the calcified deposits and effect repair.

Written by Catharine Paddock PhD

Copyright: Medical News Today