A simplified approach for real-time detection of arterial wall velocity and distension

Arterial stiffness is known to increase with age and with many vascular dis eases, but its noninvasive assessment in patients still represents a diffic ult task. The measurement of diameter change during the cardiac cycle (dist ension) has been proposed as a means to estimate arterial compliance and st iffness. Therefore, we have developed a simple PC-based device and algorith m for noninvasive quantification of vessel wall motion and diameter change in humans. This goal is achieved in real-time by processing the base-band s ignals from a commercial ultrasound Doppler system. Real-time operation is of crucial importance, because it allows a rapid achievement of optimal mea surement conditions. The system was evaluated in a laboratory using a string phantom and was tes ted on the carotid arteries of 10 volunteers. Wall velocities from 0.05 to 600 mm/s and displacements lower than 2 mum were detected with phantoms. Th e measured carotid diameter change in the volunteers ranged from 7.5 to 11. 8% (mean = 9.8%) and agrees closely with values reported in the literature. The difference between values taken one hour apart ranged from 0.2 to 0.5% . We conclude that the new system provides rapid, accurate, and repeatable measurements of vessel distension in humans.