What is intracranial atherosclerotic disease?

Intracranial atherosclerotic disease (ICAD) is one of the main causes of stroke. ICAD happens when the arteries in the brain become hard, thick and narrow. This is caused by a build-up of plaque (fatty deposits) inside the artery walls of the brain.

This narrowing of the artery walls, called stenosis, means that less blood flows to areas of the brain supplied by the affected artery. If blood flow is completely blocked, this can cause an ischemic stroke. There are two main types of ischemic stroke:

• ONE thrombotic stroke occurs when a blood clot forms in an artery that supplies part of the brain with blood
• An embolic stroke happens when a blood clot forms somewhere else in the body and then travels to an artery that supplies blood to part of the brain and blocks an artery there.

ICAD can also cause a cerebral aneurysm. An aneurysm can rupture and cause bleeding in the brain, leading to hemorrhagic stroke.

ICAD does not always cause symptoms. But when it does, the symptoms are very similar to a stroke. Signs and symptoms of ICAD may include:

If someone experiences these symptoms, they should get emergency medical attention right away, as they could be signs of a stroke.

Learn more about signs of stroke.

Who is most likely to get intracranial atherosclerotic disease?

Plaque can build up in the brain at any age – even in children – although ICAD is more common in older people. And there are certain risk factors for ICAD.

A risk factor is a condition or behavior, such as high blood pressure or smoking, that increases the likelihood of having a particular health problem compared to those who do not have the risk factor. Having a risk factor does not mean that a person will have ICAD, and not having a risk factor does not mean that they will not.

ICAD risk factors include:

Medicines or lifestyle changes can help manage some of these risk factors. People with ICAD are at higher risk of stroke, so it is important that they take steps to reduce their risk. Eating healthy and staying active can help reduce the build-up of plaque in the brain. Quitting smoking can also lower the risk of ICAD and related strokes.

Learn more about stroke prevention.

How is intracranial atherosclerotic disease diagnosed and treated?

Diagnosing ICAD

ICAD is often found only after a person has stroke-like symptoms. People who have symptoms of a stroke should go to the hospital immediately. Some treatments only work a few hours after symptoms start.

Stroke-like symptoms may include:

• Weakness
• Paralysis or numbness on one side of the body
• Vision problems
• Difficulty with speech or understanding
• Balance problems
• Difficulty swallowing

Doctors will usually order imaging tests after these symptoms to check for blockages in the brain’s blood flow or bleeding in the brain.

The most common tests for ICAD are CT (computed tomography) or MRI (magnetic resonance imaging) scans. These tests can show damage to the brain that occurs due to ICAD or a stroke.

Often, doctors will inject a person with a dye (called a contrast agent) to get clearer results from imaging tests. The dye makes it easier to see how the blood flows through the brain and any blockages or plaque build-up. Sometimes ICAD is found when the person has brain imaging done for another reason.

Learn more about neurological diagnostic tests and procedures.

People who have built up plaque in their brains — especially if they’ve already had a stroke — should have regular checkups with a doctor to help monitor their condition and manage their risk over time.

Treatment of ICAD

If a person has ICAD but has not had a stroke, treatment usually focuses on reducing the risk of having a stroke. This can include managing chronic conditions such as high blood pressure or high cholesterol – as well as lifestyle changes such as stopping smoking, adding physical activity or exercise and eating healthy.

People with ICAD may be prescribed antiplatelet medication. These help stop plaque build-up to prevent ischemic stroke. Doctors may also prescribe antiplatelet and anticoagulant medications to prevent the formation of blood clots.

In some severe cases, people may need surgery to prevent strokes. This may include angioplasty or stenting. During an angioplasty, a surgeon inserts a catheter (flexible tube) through an artery in the leg or arm and guides it through the blood vessel up to the brain.

The surgeon can then insert a small balloon into the blocked artery and inflate it. The balloon pushes down on the plaque to widen the artery so blood can flow more easily again. The compression of the plaque also keeps it attached to the walls of the artery so it cannot break free and create a blockage or embolism elsewhere in the brain.

Depending on the size and location of the artery being treated, the surgeon may also place a stent in the artery. Stents, which are a mesh of wire, help contain the plaque and can help prevent further plaque buildup if used in conjunction with medical treatment and lifestyle management of stroke risk factors.

In rare cases, people with ICAD may need a more complex operation called a cerebral artery bypass. This surgery creates a new path for blood to flow properly to the brain by removing a blood vessel from another part of the body. The surgeon then reinserts the removed blood vessel into the brain to bypass (go around) a blocked blood vessel.

What are the latest updates on intracranial atherosclerotic disease?

NINDSpart of the National Institutes of Health (NIH), is the leading federal funder of brain and nervous system research, including disorders such as ICAD. NINDS supports new and innovative research to better understand, diagnose and treat ICAD, stroke and related disorders.

NINDS created a stroke clinical trial network that serves as the infrastructure and pipeline to explore new potential treatments for people with stroke and those at risk of stroke. The NIH StrokeNet is a centralized coordinating and data management center with 27 regional coordinating centers affiliated with more than 550 stroke hospitals across the United States. It conducts small and large clinical trials and research studies to advance acute stroke care, prevention and recovery and rehabilitation after a stroke. NINDS research examines the relationship between ICAD and stroke, as well as conducts clinical trials to identify treatments for ICAD.

Learn about the latest stroke research from NINDS.

For more information on research on ICAD, check NIH REPORTERa searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.

For research articles and abstracts on ICAD and related matters, search PubMedwhich contains citations from medical journals and other websites.

How can I or my loved one help improve care for people with intracranial atherosclerotic disease?

Consider participating in a clinical trial so clinicians and scientists can learn more about ICAD and related disorders. Clinical research with human study participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed – those who are healthy or may have an illness or disease – of all different ages, genders, races and ethnicities. This helps ensure that study results apply to as many people as possible and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research, visit NINDS Clinical Trials site and NIH Clinical Research Trials and you. Learn about clinical trials currently looking for people with ICAD ClinicalTrials.gova searchable database of current and past federal and private clinical trials.

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