Atherosclerotic plaques, the build-up of fatty materials within our arteries, can develop over a long period of time without causing any symptoms.

These plaques may continue to grow and rupture causing narrowing and blockages of the blood vessels. This can lead to serious cardiovascular disease such as a heart attack or stroke causing over 160,000 deaths each year.

Lots of research has been done on why particular groups of people may develop atherosclerosis and controlling risk factors such as diabetes and high blood pressure go a long way to reduce people's risks. However, despite the treatments we have available and controlling these risk factors, some people unfortunately still go on to develop a potentially serious disease.

Further research has shown us that certain plaques in the blood vessels may be more vulnerable to rupturing compared to others. So far we know that plaques with thin caps, soft centres or those that are able to grow their own tiny blood vessels are more likely to rupture. We have now started to develop new imaging methods to try and help us detect these vulnerabilities. The hope is by being able to detect more vulnerable plaques we may be able to treat these earlier and therefore more effectively.

There are different scans available to try and visualise the tiny vessels within these plaques in the neck arteries. These include, MRI (a Magnetic Resonance Imaging scan, taking pictures using a small tunnel), CT (Computed Tomography, uses a ring-shaped machine to take pictures), and ultrasound. Ultrasound has the benefit of being free of ionising radiation and iodinated contrast, therefore posing less risk to patients. However, current ultrasound uses 2D ultrasound. Although this has shown promising results, our blood vessels and any plaques are 3D structures so we don't get to see the whole plaque using 2D imaging and therefore may miss important information. The available 3D probes in use at the moment are not able to visualise the tiny vessels accurately enough.

This study uses a different 3D ultrasound probe and ultrasound machine that is able to produce many more images than our usual probes. By taking images with this probe and using offline computer programmes to track the contrast through structures we hope that this system will be able to give us a visualisation of the whole plaque enabling us to detect any new blood vessels more accurately.

Inclusion Criteria:

1. Age>18 years old.
2. Previously consent for participation in the SECURE trial and have undergone carotid CEUS.
3. Found to have at least one carotid plaque present on carotid CEUS.
4. Able to give informed consent to participate in the study and its procedures.

Exclusion Criteria:

1. Age <18 years old.
2. Unable to provide informed consent to participate in the study and its procedures.
3. Allergy to microbubble contrast agents.
4. Known pregnancy.