Measurement of wave velocity in arterial walls with ultrasound transducers

Arterial wall stiffness can be associated with various diseases. The stiffness of an artery can be measured with the pulse wave velocity (PWV) using the "foot-to-foot" method. However, the foot of the pressure pulse is not very clear, due to reflected waves. The blood pressure pulse generated by the heart is a low frequency wave and its time resolution is low. PWV is an average indicator of artery stiffness between the two measuring positions; therefore, it cannot easily identify local stiffness. In this paper, a sinusoidally modulated force with a high frequency is generated noninvasively on the arterial wall by the radiation force of ultrasound (US). The resulting vibration in the artery is measured with an US Doppler transceiver. The wave velocity in the artery is measured from a wave image obtained by scanning the force transducer and fixing the sensor transducer. Because of the high imposed force frequency, the temporal resolution of this method is much higher than the conventional pressure PWV method. Local wave velocity more than a few millimeters can be measured, which is not possible with the PWV method.