Fig. 1.

Example cerebrovascular hemodynamic waveforms contrasting an elderly female (left) compared with young male (right). Carotid pressure waveform obtained from carotid wall distension waveform and eTracking. MCA, middle cerebral artery; W1, forward wave energy; NA, negative area (reflected compression wave energy); W2, forward expansion (i.e., suction) wave energy; ECG, electrocardiogram; PI pulsatility index; PDF, pulsatile damping factor; Ao:CCA, ratio of aortic to common carotid; PWV, pulse wave velocity.