Lab Tests and Procedures

MRI - diagnosisIf you have had a stroke or stroke warning signs, your doctor may need additional information to fully understand your problem or plan the best treatment. In addition to blood tests, you may need to schedule special tests or procedures to examine your brain, heart or blood vessels.

Here are the tests doctors use most often in stroke diagnosis. Click on the test name for more information.

Tests that View the Brain, Skull, or Spinal Cord

  • CT scan
    (CAT Scan, Computed axial tomography)
    A CT scan uses X-rays to produce a 3-dimensional image of your head. A CT scan can be used to diagnose ischemic stroke, hemorrhagic stroke, and other problems of the brain and brain stem.
  • MRI scan
    (Magnetic resonance imaging, MR)
    An MRI uses magnetic fields to produce a 3-dimensional image of your head. The MR scan shows the brain and spinal cord in more detail than CT. MR can be used to diagnose ischemic stroke, hemorrhagic stroke, and other problems involving the brain, brain stem, and spinal cord.

Tests that View the Blood Vessels that Supply the Brain

  • Carotid doppler
    (Carotid duplex, Carotid ultrasound)
    Painless ultrasound waves are used to take a picture of the carotid arteries in your neck, and to show the blood flowing to your brain. This test can show if your carotid artery is narrowed by arteriosclerosis (cholesterol deposition).
  • Transcranial doppler
    (TCD)
    Ultrasound waves are used to measure blood flow in some of the arteries in your brain.
  • MRA
    (Magnetic resonance angiogram)
    This is a special type of MRI scan (see above) which can be used to see the blood vessels in your neck or brain.
  • Cerebral arteriogram
    (Cerebral angiogram, Digital subtraction angiography, [DSA])
    A catheter is inserted in an artery in your arm or leg, and a special dye is injected into the blood vessels leading to your brain. X-ray images show any abnormalities of the blood vessels, including narrowing, blockage, or malformations (such as aneurysms or arterio-venous malformations). Cerebral arteriogram is a more difficult test than carotid doppler or MRA, but the results are the most accurate.

Tests that View the Heart or Check its Function

  • Echocardiogram
    (2-d echo, Cardiac echo, TTE, TEE)
    Painless ultrasound waves are used to take a picture of your heart and the circulating blood. The ultrasound probe may be placed on your chest (trans-thoracic echocardiogram, TTE) or deep in your throat (trans-esophageal echocardiogram, TEE).
  • Electrocardiogram
    (EKG, ECG)
    This is a standard test to show the pattern of electrical activity in your heart. 3-10 electrical leads are attached to your chest, arms and legs. Sometimes the EKG is recorded continuously over days, with the signals sent to a portable recorder (Holter monitor) or by radio to a hospital monitoring station (telemetry).

Routine Screening Tests

  • Chest x-ray
    (CXR)
    An x-ray of the heart and lungs is a standard test for patients with acute medical problems. Abnormalities may alert your doctor to important problems such as pneumonia or heart failure.
  • Urinalysis
    (UA)
    A urine sample is often obtained to screen for bladder infection or kidney problems. If infection is suggested, a urine culture test may be required.
  • Pulse oximetry
    (Blood oxygen)
    This painless test is sometimes done in the emergency room or hospital to determine if your blood is receiving enough oxygen from the lungs. A small probe with a red light is usually attached to one finger.

Other Neurologic Tests

  • Electroencephalogram
    (EEG)
    The EEG measures your brain waves through several electrical leads painlessly attached to your head. EEG is not routinely used for stroke diagnosis, but would be ordered if your doctor thinks that you may have had a seizure.
  • Lumbar puncture
    (LP, spinal tap)
    A needle is inserted in your lower back to obtain a sample of the fluid (cerebrospinal fluid, CSF) which surrounds your brain and spinal cord. LP is not routinely used for diagnosis of ischemic stroke. However, LP is often required if subarachnoid hemorrhage (bleeding from a cerebral aneurysm) is suspected. LP may also be needed if your doctor suspects a nervous system infection (such as meningitis) or inflammation.
  • Electromyogram / Nerve conduction test
    (EMG / NCV)
    This test records the electrical activity of the nerves and muscles. EMG is not used for stroke diagnosis, but might be needed if your doctor suspects a problem with the nerves in your arms or legs.
  • Brain biopsy
    This is a surgical procedure in which a small piece of the brain is removed for microscopic examination. Biopsy is used to diagnose lesions (such as tumors) which cannot be identified by CT or MRI scan. It is very rarely used for stroke diagnosis, often only when cerebral vasculitis is suspected.