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As vascular experts, interventional radiologists treat atherosclerosis, "hardening of the
arteries," throughout the body. In some patients, atherosclerosis, specifically in the
carotid artery in the neck, can lead to ischemic stroke. Plaque in the carotid artery may
result in a stroke by either decreasing blood flow to the brain or by breaking loose and
floating into a smaller vessel, depriving a portion of the brain of blood flow. In patients at
high risk of having a stroke, the narrowed section of artery may be reopened by an
interventional radiologist through angioplasty and reinforced with a stent, thereby
preventing the stroke from occurring. Vascular stents are typically made of woven, laser-
cut or welded metal that permits the device to be compressed onto a catheter and
delivered directly into the hardened artery. In addition to diagnosing and treating those at
risk for stroke, interventional radiologists use their expertise in imaging, angioplasty and
stenting to treat those having an acute stroke.
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Patients can also take action to prevent strokes by:
- Stop smoking
- Controlling high blood pressure
- Lowering cholesterol levels
- Maintaining healthy weight
- Exercising
- Utilizing appropriate medications like aspirin,
prescription drugs like anticoagulants
- Treating carotid artery disease
- Treating unruptured cerebral aneurysm or arteriovenous
malformation
Assessing Patients at Risk for Carotid Artery Disease and Future Stroke
Physical examination. Your doctor
may be able to assess your risk for stroke during a routine
physical examination. If your physician suspects that you may be
at high risk, he or she will ask if you have experienced symptoms
such as numbness or muscle weakness, speech or vision
difficulties, or lightheadedness. By listening to the carotid
artery through a stethoscope, the doctor may hear a rushing
sound, called a bruit ("brew-ee") that suggests the
artery may be obstructed. Physical exam is not always accurate,
however, and further tests may be ordered.
Ultrasound. A technique
called doppler ultrasound that creates pictures using
sound waves can determine whether there is blockage in
the arteries that carry blood to the brain. Some
physicians recommend ultrasound screening for those who
have been diagnosed with atherosclerosis or other risk
factors for carotid artery disease. In the ultrasound
image shown here, the colors red and blue indicate direction of flow. |
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Magnetic Resonance Angiography (MRA).
This is a non-invasive diagnostic technique that creates an image
of the arteries in the brain. A magnetic resonance (MR) scanner
uses harmless but powerful magnetic fields and radio waves to
create detailed images of the body's tissues.
Diagnosis
There are a number of diagnostic exams that can be performed to determine if someone has had a stroke or is at risk for having one.
When a Stroke Is Suspected
A CT scan. The area affected by stroke is purple.
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Computed tomography (CT). The first diagnostic test performed in the emergency room is usually a CT scan. CT uses computers to generate detailed pictures of the brain, and can confirm the diagnosis of stroke and tell whether the stroke is caused by a hemorrhage in the brain.
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Patient having an angiogram
Magnetic resonance imaging
(MRI) is a diagnostic test which may be performed to
identify and further localize the site of the stroke and
find the source. It may be able to quickly identify the
area deprived of sufficient blood flow and guide further
therapy. In the MR Image, the arrow points to the area
affected by a stroke. |
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Angiography. An angiogram
is an X-ray in which a contrast agent, or dye, is
injected into a vein to highlight the blood vessels. With
this exam, radiologists can pinpoint the exact location
of blockage or bleeding in the brain. Angiography also is
used to guide thin tubes called catheters to the site of
the problem and administer treatments. |
Treatment
Interventional radiologists are a critical part of the stroke team in hospitals and are actively involved
in creating more stroke teams across the country. Stroke teams generally consist of emergency room physicians,
neurologists, and interventional radiologists.
For those having a stroke, it must first be determined which kind of a stroke the patient is having so the
proper treatment can be given. The interventional radiologist interprets the non-contrast CT (computed tomography)
imaging to determine if acute stroke patients are candidates for clot-busting drugs. CT is quick, inexpensive,
and readily available.
If the stroke is determined to be ischemic (due to a blood clot), the interventional radiologist will
assess what caused the clot, such as a clogged carotid or other artery, and can correct the underlying problem to
prevent future strokes from occurring.
Treatment To Dissolve Blood Clots
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If the stroke is due to a blood clot, a clot-busting drug, tPA (tissue plasminogen activator)
can be given intravenously to break up or reduce the size of blood clots to the brain.
This technique must be performed within three hours from the onset of symptoms.
When therapy cannot be initiated within three hours or when treatment with tPA during the
first three hours is not sufficient to dissolve the blood clot, interventional radiologists (IR) that
specialize in neurological procedures can provide intra-arterial thrombolysis treatment.
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Using x-ray guidance, an IR will insert a catheter through a nick in the skin at the groin and advance
it through the femoral artery in the leg all they way to the tiny arteries in the brain where they place
the clot-busting drug directly on the clot or to break up the clot mechanically.
When given locally this way, the tPA can be administered up to six hours
after the onset of stroke symptoms. In many cases, the ambulance drivers will take a stroke victim past
the three-hour window directly to the interventional radiology suite for assessment for this direct
thrombolytic therapy. Often a significantly disabled stroke patient who receives this treatment can
return to normal life with minimal or no after effects from the stroke.
The interventional radiologist will also assess what caused the clot, such as a clogged
carotid or other artery, and can correct the underlying problem to prevent future strokes
from occurring. Unfortunately, many hospitals in this country do not have stroke teams
that can rapidly assess patients and provide treatment within the three-hour window.
Interventional radiologists are actively involved in creating more stroke teams across the
country. Stroke teams generally consist of emergency room physicians, neurologists and
interventional radiologists.
 Before tPa therapy |
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 After tPa therapy |
Treatment for Hemorrhagic Stroke
Interventional neuroradiologists can also treat ruptured
aneurysms inside the brain causing hemorrhage into the
subarachnoid space, which can cause stroke or death. During the
embolization technique, an interventional neuroradiologists
inserts a catheter through a nick in the skin of the groin and
advances it to the site of the ruptured blood vessel. An
embolizing agent (a substance that clots or closes off the
bleeding blood vessel) is injected under X-ray guidance. Most
commonly, tiny metal coils are used to embolize and block the
abnormal blood vessel or aneurysm. The catheter is withdrawn and
the coils remain to provide the occlusion. The same technique can
be used to treat aneurysms and AVMs before they rupture. Surgery
had been the primary treatment available until the platinum coil
device was approved by the FDA in 1995.
Stroke Facts and Statistics
- Nearly half of all stroke fatalities occur before
emergency medical personnel arrive.
- 1.1 million Americans live with disabilities caused by a
stroke.
- 600,000 Americans will have a new or recurrent stroke
each year—of these, 160,000 will die.
- Stroke is a medical emergency with a narrow time frame
for treatment—people should call 911 immediately.
- Strokes can be treated intravenously with the
clot-busting drug, tPA (tissue plasminogen activator), if
it is given within three hours of the onset of symptoms.
- Persons who have a transient ischemic attack (TIA), also
known as a mini-stroke, are likely to have another one.
Transient ischemic attacks cause brief stroke symptoms
that go away. People often ignore these symptoms, but
they are an early warning sign and 35 percent of those
who experience a TIA will have a full-blown stroke if
left untreated.
- Stroke is not just an older person’s disease—28
percent of strokes occur in people under age of 65.
- More men than women have strokes—although more women
die from them.
- African Americans are at much higher risk for stroke. In
part, this is because African Americans are at increased
risk for obesity, high blood pressure and diabetes, which
increase the risk of stroke.
- May is Stroke Awareness Month.
