Methods of Determining the Distensibility of Blood Vessels

Methods of calculating the characteristic transmission parameters of arterial segments, which are very short compared to the wavelength, are presented. If the reflection coefficient is known (e.g., as with complete occlusion) two simultaneous measurements of pressure or flow suffice (Method I). If this is not known, as is generally the case, three measurements must be made (Method II). In either case, provided great attention is paid to the static and dynamic calibrations of the instruments, the results obtained are wholly reasonable and allow an estimation of vessel distensibility, and also a closer examination of the usefulness of various transmission-line hypotheses.