New Doppler Signal Processor for Arterial Relative Section Evaluation

A new device has been developed that is capable of processing information from a standard Doppler signal on the relative section (RS) of arteries during the cardiac cycle. RS is a new parameter proportional to the vessel cross-section and its changes during the cardiac cycle. This parameter does not give any morphologic information on the vessel itself, but it can help in completing Dop pler analysis, providing information on vessel elasticity. RS radius (R) and ve locity (V) (traditional Doppler) signals were routinely recorded under constant-pressure conditions. The device was tested in vivo by recording the R and V tracings on 20 common femoral arteries (cf) in dogs. These measure ments were compared with the R and V tracings obtained from the largest femoral branch (fb). R and V tracings were also obtained on 20 femoral arteries after surgically induced stenosis (above, at, and below the stenosis). Both exper iments showed a significant depression of the R tracings (p < 0.01). No signifi cant difference was found between the radius value and three-projection angiography of the stenosis (p=ns). The ability of the device to determine the elasticity of the arterial wall was evaluated in vitro on 10 specimens of athero sclerotic human tibial arteries, obtained from amputated lower extremities, and on 10 samples of dog femoral arteries, and the evaluations were compared. A significant difference in the radius root mean square values was found between the 2 groups (p < 0.01). The authors conclude that this device is capable of determining a new parameter (RS) that is proportional to the cross-section of the examined artery. They have also demonstrated that RS provides useful in formation about arterial wall elasticity.