Figure 5.

Cross-sectional area of the brachial artery from transverse ultrasound images. The upper waveform shows the automatically calculated cross-sectional area of the brachial artery from ultrasound video acquired in transverse view over seven cardiac cycles. The lower gray waveform is the ECG recorded simultaneously and then automatically extracted. The minima of the diameter waveform correspond to end diastole. A_TRV is mean area. The peak-to-peak area A_PP is a measure of arterial distention.