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 buildup of plaque (fatty deposits) inside the artery walls in the brain.
This narrowing of artery walls, called stenosis, means less blood flows to areas of the brain supplied by the affected artery. If the blood flow is blocked completely, this can cause an ischemic stroke. There are two main types of ischemic strokes:
- A thrombotic stroke happens when a blood clot forms in an artery that supplies blood to part of the brain
- 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, blocking an artery there.
ICAD can also cause a cerebral aneurysm. An aneurysm can burst and cause bleeding in the brain, leading to hemorrhagic stroke.
ICAD doesn’t always cause symptoms. But when it does, the symptoms are very similar to a stroke. Signs and symptoms of ICAD may include:
If someone is experiencing these symptoms, they should get emergency medical care right away, as they may be signs of a stroke.
Learn more about the 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, like high blood pressure or smoking, that increases the likelihood of having a certain health problem compared to those who don't have the risk factor. Having a risk factor doesn't mean a person will have ICAD, and not having a risk factor doesn't mean they won’t.
ICAD risk factors include:
- Diabetes
- High blood pressure
- High cholesterol
- Cigarette smoking
- Age
- Family history of stroke
Medicines or lifestyle changes can help manage some of these risk factors. People with ICAD are at higher risk of stroke, so it’s important that they take steps to reduce their risk. Eating healthy and staying active can help reduce the buildup of plaques in the brain. Quitting smoking can also lower the risk of ICAD and associated strokes.
Learn more about preventing stroke.
How is intracranial atherosclerotic disease diagnosed and treated?
Diagnosing ICAD
ICAD is often found only after a person has stroke-like symptoms. People having symptoms of stroke should go to a 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 imagery) scans. These tests can show damage in the brain that happens because of 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 blood is flowing through the brain and any blockages or plaque buildup. 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 plaque buildup in their brains—especially if they’ve already had a stroke—should have regular check-ups by a doctor to help monitor their condition and manage their risk over time.
Treating ICAD
If a person has ICAD but hasn’t had a stroke, treatment usually focuses on lowering their risk of having a stroke. This may include managing chronic conditions like high blood pressure or high cholesterol—as well as lifestyle changes like quitting smoking, adding physical activity or exercise, and healthy eating.
People with ICAD may be prescribed antiplatelet medicines. These help stop plaque buildup to prevent ischemic stroke. Doctors may also prescribe antiplatelet and anticoagulant medicines to prevent the formation of blood clots.
In some severe cases, people may need surgery to prevent stroke. 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 threads 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, allowing blood to once again flow more easily. The compression of the plaque also keeps it pinned to the walls of the artery, so that it can’t break loose and create a blockage, or embolism, somewhere else 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 wire mesh, help contain the plaque and may help prevent additional plaque buildup if used with medical and lifestyle management of stroke risk factors.
In rare cases, people with ICAD may need a more complex surgery called a cerebral artery bypass. This surgery creates a new path for the 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?
NINDS, a part of the National Institutes of Health (NIH), is the leading federal funder of research on the brain and nervous system, including disorders like ICAD. NINDS supports new and innovative research to better understand, diagnose, and treat ICAD, stroke, and related disorders.
NINDS created a stroke clinical trials network that serves as the infrastructure and pipeline for exploring new potential treatments for people with stroke and those at risk for stroke. The NIH StrokeNet is a centralized coordinating and data management center with 27 regional coordinating centers that are linked to more than 550 stroke hospitals across the U.S. It conducts small and large clinical trials and research studies to advance acute stroke treatment, prevention, and recovery and rehabilitation following a stroke. NINDS research is investigating the relationship between ICAD and stroke, as well as conducting clinical trials to identify treatments for ICAD.
Learn about the latest stroke research from NINDS.
For more information on research about ICAD, check NIH RePORTER, a 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 summaries on ICAD and related conditions, search PubMed, which contains citations from medical journals and other sites.
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, sexes, races, and ethnicities. This helps make sure 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 the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with ICAD at ClinicalTrials.gov, a searchable database of current and past federal and private clinical trials.
Where can I find more information about intracranial atherosclerotic disease?
Information may be available from the following sources: