Investigations after Stroke or Transient Ischemic Attack (TIA)
Carotid Doppler Test
Carotid doppler ultrasound is a non-invasive test that uses sound waves to measure the flow of blood through the large carotid arteries that supply blood to the brain. These arteries can become narrowed due to atherosclerosis (furring up) or other causes, and this can lead to transient ischemic attack (mini-stroke) or stroke. The carotid doppler test can help doctors determine stroke risk and the need for preventive measures.
A carotid doppler test may be performed if you are considered to be at risk of having a stroke due to decreased blood flow in the carotid arteries.
It is a non-invasive procedure, and no special preparations are necessary. The ultrasound technician will apply a jelly-like substance to both sides of your neck, where the carotid arteries are located. This helps lubricate the skin and allow the ultrasound sensor to move more freely. The sensor is moved back and forth over the neck and generates sound waves that bounce off the arteries. The echo that bounces back is measured, and the changes in frequency can measure the flow of blood. The flow will be different in areas that are narrowed.
This test takes an average of 15 to 30 minutes for most people, though it can vary. Once the test is completed, you will be free to resume normal activities with no restrictions.
An echocardiogram is a test that uses sound waves to create a moving picture of the heart. It allows doctors to see the heart beating, and to see many of the structures of the heart in a noninvasive way. A trained sonographer performs the test. You will be asked to remove your clothes from the waist up and lie on an examination table on your back. A gel will be spread on your chest and then an instrument called a transducer that transmits high-frequency sound waves is applied. The transducer picks up the echoes of the sound waves and transmits them as electrical impulses. The echocardiography machine converts these impulses into moving pictures of the heart. The probe records the motion of the blood through the heart.
An echocardiogram can help to identify heart problems that may cause blood clots to form.
ECG (electrocardiogram) is a test that measures the electrical activity of the heart. Your chest area is cleaned with alcohol and electrodes are stuck on. The electrical impulses made while the heart is beating are recorded and shown on a piece of paper. Any problems with the heart's rhythm can be identified, to enable the correct treatment.
24 Hour Tape ECG Monitoring
Some problems, like palpitations, are difficult to identify during routine heart examinations as they only happen now and then. 24 Hour Tape Monitoring is a test carried out to monitor your heart during your normal daily activities, over a 24 hour period. You will not be required to stay in hospital for the monitoring. Your chest area is cleaned with alcohol and electrodes are stuck on. Wires from the electrodes connect to a small tape recorder on a belt worn around your waist. You can carry out normal activities and you keep the monitor on all day and night. You will be asked to return to the hospital the next day to return the monitor and its recordings.
A CT (computerised tomography) scanner is a special kind of X-ray machine. CT scans are far more detailed than ordinary X-rays and give multiple cross-section pictures through the body. The scanner is particularly good at testing for bleeding in the brain so it will identify what kind of stroke you have had.
Magnetic Resonance Imaging (MRI) scan
MRI scans use strong magnetic fields and radio waves to produce a detailed image of the inside of the body.
Diffusion Weighted MRI (DWI MRI)
Is a type of scan used to identify areas of an organ, such as the brain, which have recently been damaged. The MRI machine is set to detect small restrictions in the movement of water molecules inside the injured areas. These small changes are detected by the MRI machine and appear as bright spots on the screen.
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