What Is Diagnostic Radiology?

Immediate treatment after a stroke includes diagnostic imaging.

Photo © A.D.A.M.

Definition: Diagnostic radiology is a field of medicine that using imaging technology to see structures within the body. Radiologists are medical doctors who specialize in the field of radiology.

Diagnostic radiology is used to determine the cause of symptoms, monitor how the body responds to treatments a patient is receiving for a medical condition and, screen for various illnesses such as cancer and heart disease.

Diagnostic radiology is used for patients who have had a stroke. Treatment of stroke will depend on the type of stroke a patient has had – either ischemic stroke or hemorrhagic stroke.

Immediate treatment after a stroke can save lives and reduce the damaging effects of a stroke by restoring blood flow after an ischemic stroke or controlling bleeding and reducing pressure on the brain after a hemorrhagic stroke.

Imaging protocols for patients differ depending on the amount of time that has passed since the onset of the stroke. If a patient arrives at the hospital within three hours of a stroke most often they will undergo a noncontrast CT scan to look for hemorrhage to determine the type of treatment the patient should receive. If there is no hemorrhage, most patients can be treated with thrombolysis. After the initial three hours, treatment options are different and imaging becomes more complex.

To evaluate whether the patient has experienced an ischemic or hemorrhagic stroke, a computed tomography (CT) scan or magnetic resonance imaging (MRI) of the head is typically performed.

  • CT scan of the head
    A CT scan is a technological combination of specialized X-ray equipment with computers to produce multiple images of the brain. To enhance the imaging, a contrast material may be used to improve the scan and aid in the detection of the stroke. If there is blood flow a CT perfusion (CTP) may be performed at the same time.
  • MRI of the head
    An MRI uses a magnetic field to produce images of the cerebral vessels, also known as an MR angiography (MRA). Images of blood flow can be obtained with an MR perfusion (MRP).

Other tests may be performed, after a neurological evaluation, to further identify the type, location, and cause of the stroke. They are also used to rule out any other disorders. In addition to blood tests, these tests include:

  • Electrocardiogram (ECG or EKG)
    An electrocardiogram is conducted to check the electrical activity of the heart. It can also determine whether a heart condition was the cause of the stroke.
  • Carotid ultrasound
    Also known as a Doppler ultrasound, high-frequency sound waves are used to check for a narrowing or blockage of the carotid arteries located on each side of the neck. The carotid arteries carry blood from the heart to the brain.
  • Cerebral Angiography
    A cerebral angiography is performed in order to view the major blood vessels in the brain. It will help to detect or confirm abnormalities that exist, such as a blood clot or narrowed arteries.
     
  • Electroencephalogram (EEG)
    An EEG measures the electrical impulses of the brain and records the electrical impulses related to hearing, vision, and body sensations.

Another diagnostic test that may be performed includes a lumbar puncture, or spinal tap, to collect samples of the fluid that ​surrounds the brain and spinal cord.

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