An experimental comparison of the signal from laminar and disturbed blood flow

In order to determine the limiting velocity resolution that can be achieved using ultrasound, we have completed an experimental evaluation of the statistics of the received signal from laminar flow and disturbed flow following the transmission of a train of short pulses. Experimental rf M-mode images are presented using a high volume concentration of scatterers in a blood mimicking solution. For laminar flow, when a significant range of velocity components is present within the sample volume, this range is the limiting factor in the length of the correlated signal interval. In addition, we have studied the disturbed flow that occurs distal to a 50% stenosis. Particularly for the low velocities that would be associated with diastole, the duration of the signal correlation increases in a spatial region that is distal to the stenosis and near the vessel walls, rather than the expected decrease