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At the hospital, medical personnel will use one of more
of the following diagnostic tests to determine the type
of stroke and its location. 
Computed Axial Tomography
(CT scan, CAT scan): CT is a non-invasive,
painless test that uses x-rays to produce a three-dimensional
image of the interior of the patient’s head. An
initial CT scan can quickly rule out hemorrhage or a
brain tumor causing stroke-like symptoms. It may even
show areas of the brain that are in danger of dying
but still salvageable.
 |
| CT
scan of a patient who has had a left middle cerebral
artery stroke. The arrow indicates the location
of the stroke. |
Magnetic Resonance Imaging
(MRI scan, MR scan): This is a non-invasive,
painless test that uses magnetic fields to produce a
three-dimensional image of the interior of the patient’s
head. An MRI scan shows the brain and spinal cord in
more detail than a CT scan does. MRI can be used to
diagnose ischemic stroke, hemorrhagic stroke, and other
problems involving the brain, brainstem, and spinal
cord.
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| MRI
of a patient who has had a stroke of the left hemisphere
of the brain. The arrow indicates the area that
was affected. |
Carotid Ultrasound (Carotid
duplex, Carotid doppler): This non-invasive
test uses ultrasound waves – painless high-frequency
radio waves – to take a picture of the carotid
arteries in the patient’s neck and show the blood
flow to the brain. It can show if the patient’s
carotid artery is narrowed or blocked by atherosclerosis
(hardened plaque buildup on the vessel wall).
 |
| Left
shows carotid doppler image of a normal carotid
artery. Right shows a stenosis at the origin of
the carotid artery. |
Cerebral Angiography:
(Cerebral arteriogram, Digital subtraction angiography
[DSA]): This is a minimally invasive
test in which a thin, flexible catheter is inserted
into an artery, usually in the patient’s groin,
and steered through the blood vessels toward the brain.
A special dye, which can be seen on x-rays, is injected
through the catheter into the blood vessels leading
to the brain. X-ray images show any abnormalities of
the blood vessels, including narrowing, blockage or
malformations (such as aneurysms or arteriovenous malformations).
Cerebral arteriogram is a more difficult test than carotid
ultrasound, MRA or TCD, but the results are the most
accurate. However, this method may not detect some aneurysms
due to overlapping structures or spasm.
 |
| An
angiogram showing one of the major blood vessels
of the brain that is blocked causing a stroke (arrow
indicates the location of the blockage). |
Computed Tomographic
Angiography: (CT-angiography, CT-A,
CTA)
CT-A is a recent development in diagnostic imaging for
stroke that is poised to replace traditional cerebral
angiography. It is much less invasive, as it does not
require arterial catheterization, and results are available
in about half the time. It can also catch aneurysms
that cerebral angiography may miss. CT-A combines a
regular CT scan with a contrast dye injected directly
into a vein. The dye travels to the brain arteries,
and images are created using a CT scan. These images
show exactly how blood flows into the brain arteries.
 |
| An
example of a CT angiogram of the circulation of
the brain. |
Magnetic Resonance Angiography
(MRA): This is a special type of MRI
scan used to see the blood vessels in the neck or brain.
It can help determine the extent of damage.
 |
| MRA
of a patient showing the carotid artery circulation.
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Transcranial Doppler:(TCD)
: TCD uses ultrasound waves to measure blood
flow in some of the arteries in the brain.
 |
Top
shows a TCD of a normal artery. Bottom shows a
severely stenosed internal carotid artery. |
Though not routine, certain blood tests may used for
specific stroke situations or when the cause of stroke
is unclear (for example, in a young person without known
stroke risk factors). Abnormal results may suggest a
cause for the stroke. For example, a toxicology screen
would show the presence of cocaine, which is a serious
risk factor for stroke.
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Diagnosis
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