What is Transcranial Doppler (TCD)? TCD is a machine that uses ultrasound (similar to the ultrasound that is used during pregnancy) to detect areas of increased blood flow in the blood vessels of the brain. When blood vessels are narrowed due to sickle cell damage, the blood makes a louder noise as it travels through the narrow area. This is like the noise in a water hose when you make the hose bend. If there is faster flow, that means that the blood vessel may be narrower, and there is a greater risk of possibly having a stroke in the future. What is a stroke? Strokes occur because of a problem with the blood circulation to the brain. In children, strokes usually result from narrowing or closure of the arteries—the vessels that bring blood to the brain. If the blood flow is decreased, parts of the brain do no get the oxygen that is necessary for the brain to function, and may result in problems such as weakness in an arm or leg, difficulty talking or understanding what others are saying, memory problems, or other losses of brain function. These problems may be transient (short lived) or permanent. http://www.scinfo.org/tcdinfor.htm

Correction: What is a crainial doppler? What is it used for? Who created the doppler equations? When? Correction: ( This actually Courtesy of Tech Brian at the Fish Hospital in Deltona Florida. Not the Griffin Hospital.)