Basically 2 methods are available to transcutaneously assess the compliance of arteries using ultrasound. One method is based on the pulse wave velocity (mean compliance over a segment), while the other is based on the local distension waveform of an artery (local compliance). Both methods assume compliance to be independent of local blood pressure. The latter method requires accurate assessment of the diameter of the artery under investigation at the onset of a cardiac cycle, the distension during the cardiac cycle and the local pulse pressure. A new method is described to obtain reliable estimates for the arterial diameter and the change in diameter as function of time.