Stroke Tests & Diagnosis
Because ischemic and hemorrhagic strokes involve vastly different types of treatment, doctors usually run diagnostic tests to first correctly identify the presence and type of stroke. Diagnostic tests can also help rule out other conditions that may mimic the symptoms of stroke.
The doctor will begin with a physical examination and ask questions regarding the patient's medical history. It is important at this time to let your health care provider know about any family history of heart or blood problems. Questions regarding initial signs of stroke symptoms and medications taken will also be asked. Blood pressure and pulse will also be taken for signs of atherosclerosis (hardening of the arteries due to cholesterol buildup), a common contributing factor for stroke. By doing so, doctors may get a clearer picture on a patient's neurological status and better dictate the severity of the stroke.
During the physical examination, the doctor may also perform a responsive test, sometimes known as an "evoked response test," to measure the affected individual's visual, auditory and physical reactions. The physician may use a light, sound or physical stimulus during the test to help determine the area of the brain that is affected by stroke and not functioning properly. For example, if a patient is having reaction problems in the left side of the body, then it may be an indication that the right side of the brain is experiencing a stroke. The two most commonly used methods for stroke diagnosis are CT scans and MRI scans.
CT Scans (computerized tomography): A specialized type of CT scan, known as a CTA, can usually show stroke sites in the brain. In this procedure, a type of contrast dye is injected into the blood, and a detailed 3D image of the blood vessel surrounding the neck and brain is visualized with the help of X-ray beams. Doctors then search the image for aneurysms and clots and evaluate the arteries for hemorrhage sites. If used without the contrast dye, the images can confirm the presence of hemorrhage, but with fewer details of the actual blood vessels. For individuals with kidney problems, pregnant women or elderly patients, CT scans are usually run without contrast, as the dye may cause other medical complications. CT scans usually takes a few minutes to complete.
MRI Scans (magnetic resonance imaging): In MRI scans, strong magnetic fields and radio waves are used to produce a 3D image of the brain so the doctor can detect damaged brain tissues in ischemic strokes. They can also detect other brain abnormalities, such as tumors, so the health care professional can rule out other medical conditions that share similar symptoms with stroke. Sometimes, doctors may choose to perform the scan with contrast dye to evaluate arteries in the brain and neck. This type of imaging can also be used to detect chronic hemorrhages. MRIs typically take about an hour.
Sometimes, other tests and imaging may be also performed along with CTs and MRIs to help the doctor determine the underlying cause of the stroke. Other types of tests include but are not limited to the following:
- Blood tests: Additional blood tests may be run to help determine glucose and cholesterol levels, as well as blood chemical balance. They can also help detect signs of infection that may need to be treated along with the stroke symptoms. Blood tests can also rule out any other blood abnormalities or medical conditions that may require an altered treatment for stroke.
- Carotid phonoangiography: In a phonoangiography, the sounds of blood flow near the carotid artery are recorded to determine the presence of blockage. In individuals with a healthy heart, blood flow would be steady and constant, but in the presence of blood clots, the blood flow would be disrupted and uneven.
- Arteriography: in this procedure, the doctor will insert a thin, flexible catheter from the groin into the major carotid or vertebral artery. Then, a dye will be injected to show contrast, so an image of the arteries around the head area can be taken and searched for signs of blockage. The images also allow the doctor to observe blood flow through the brain.
- Electrocardiogram (EKG) and echocardiogram: Both these tests can help create images of the heart and track its electrical activity to help the doctor identify whether or not the source of the thrombus is the heart. Echocardiography may be obtained by swallowing a flexible probe with a built-in transducer to take an ultrasound image.
- Doppler ultrasound: A Doppler ultrasound of the carotid arteries can detect constricted vessels as well as the location of a blockage. This test is run via high-frequency sound waves that change according to the blood flow. In blockage areas, where there is no blood flow, there will also be no sound.
The sooner you see a doctor, the better the prognosis for stroke treatment will be. Therefore, it is very important to seek emergency care immediately upon the first signs of stroke symptoms.