Stroke

A stroke occurs when part of the brain is deprived of the blood supply that brain cells need to survive. A stroke can result from anything that impairs the blood flow to the brain causing the brain to be deprived of oxygen, which damages the tissue. Symptoms of that damage can be a loss of balance, slurred speech or paralysis.

Diagnosing Stroke

There are a number of ways to detect whether a patient has had a stroke and determine what kind of stroke has occurred, where it has occurred and the damage which it has caused.

Modalities used to detect a stroke:

• CT Scan - usually the first test done when a patient comes to a hospital emergency room with stroke symptoms. The test uses low-dose X-rays to show an image of the brain and it can determine whether a stroke is caused by a blockage or a bleed, and the size and location of the stroke\
  
• MRI - is best for strokes that involve small blood vessels.
  
• Transcranial Doppler - This is a portable test that can be performed at the bedside to assess blood flow through the vessels in the brain. A small probe is placed against the skull
  
• Doppler Ultrasound - This is a painless, noninvasive test in which waves of sound above the range of human hearing are sent into the neck. Echoes from the waves bounce off the moving blood and tissue and are formed into an image.
  
• Carotid Ultrasound - is conducted without entering the body and it evaluates the blood flow of the carotid arteries. Gel is used on the skin to send an ultrasound signal and a computer can calculate how fast the blood is travelling. This helps doctors determine how narrow an artery has become.
  
• Arteriography - an X-ray of the carotid artery taken when a special dye is injected. This technique carries its own small risk of causing a stroke and it's expensive, but it is a reliable way to measure blockage of the carotid arteries. Some people may experience a sensation of pressure or warmth. It involves insertion of a catheter into a blood vessel.

Treatment
The course of treatment for a stroke depends on what caused it:

• A blood clot or material fragment from another part of the body lodging in a blood vessel to the brain. This is the most common cause of stroke.
  
• Narrowing of the blood vessels to the brain.
  
• Deposits of cholesterol or other fatty materials in the blood vessels.
  In many causes the stroke it treated with drug therapy.