Elasticity measurement in vascular tissues by a new H-R spectral estimation of transient resonant high-overtones in noisy echo-signals

In order to get an estimator of the state of the arterial tissues in non-intrusive way, with the aim of preventing vascular accidents, some type of pulsed ultrasonic energy must be employed. But, the conventional pulse-echo ultrasonic imaging only provides a very limited spatial resolution (around hundreds of microns), so reducing the potential accuracy of these classical tools to know elastic properties in parietal tissues of the arteries with resolution enough. In this paper, a new spectral estimation of pulsed ultrasonic echoes and an experimental set-up for its laboratory emulation, both developed by the paper authors, are described. This estimation is based on analyzing with very-high resolution the spectral location of higher overtones in the repetitive pulse-echo signals, acquired from our experimental disposition mimicking the real arterial circulation. This new procedure achieves a radically better estimation (one / two magnitude orders) of the arterial elasticity, in comparison with previous ultrasonic methods. This proposal opens a new way to perform a non-invasive artery diagnosis, based on to accurately estimate its wall elasticity. This provides improvements in the effective resolution finally attainable, also for the real noisy echo-signal received from biomedical tissues. These finding have been corroborated in laboratory with ex-vivo arterial segments.