Apply enough ultrasound gel to cover the surface of the transducer.Īlert the subject that the gel may feel cold, then place the transducer on the temporal window. If the subject is an adult, set the depth to 50 millimeters, which is the average midpoint depth for the M1 segment of the MCA. Set the high pass filter cutoff between 50 and 150 hertz. Set the gain at a medium level, with the goal of keeping background noise at a minimum. If the signal is difficult to find, increase the gate size to increase the intensity of the signal. Set the sample volume to eight to 12 millimeters during the initial search for the MCA signal. Once the MCA signal is located, reduce the power as much as possible while still maintaining a good signal. Keep the power at a reasonably high value during the initial search for the middle cerebral artery or MCA. Second, a crucial part of learning functional TCD is learning the sounds associated with the different arteries.īegin by setting the parameters for a transcranial Doppler ultrasound or TCD. First, it is helpful to see exactly where to place the transducer. Visual demonstration is important for two reasons. Practice on as many volunteers as you can find. The fine motor control needed for making small adjustments in transducer position and direction takes time to develop. It is crucial to hold the transducer steady and move very slowly. Finding the middle cerebral artery using TCD takes practice. The main advantage of functional TCD is its high temporal resolution measurement of changes in cerebral blood flow. This protocol forms the basis for a functional TCD experiment because almost all functional TCD experiments require placement of a fixation device to record a stable signal over an extended period of time.
0 kommentar(er)
