Abnormal fetal cardiovascular physiology Elevated fetal middle cerebral artery peak systolic velocity 2022-03-12T23:26:48Z Increased peak systolic velocity of the fetal middle cerebral artery (MCA) as evaluated by Doppler ultrasound. The technique for MCA peak systolic velocity measurement involves an axial section through the fetal head that includes the thalami and cavum septum pellucidum is obtained and the circle of Willis visualized with color or power Doppler. The MCA is examined close to its origin from the internal carotid artery. The sample volume should be placed in the center of the vessel and the angle between the ultrasound beam and the direction of blood flow kept as close to 0 degrees as possible. Angle correction can be used if required. The highest peak systolic waveform is measured, in the absence of fetal breathing movements. An elevated MCA Doppler measurement indicates that the fetus is likely to be anemic, but this measurement is not perfectly sensitive or specific.