Vascular Ageing' refers to age-related impairment in the structure and function of arterial blood vessels. Monitoring of early vascular aging (EVA) is a recently proposed strategy for early screening. Arterial stiffening is established as a unique and reliable identifier of early vascular aging. The primary early manifestations of arterial stiffening include – (a) Loss of endothelial function, (b) Loss of compliance, (c) elevation of central blood pressure, and (d) onset of structural remodeling. There is no single device that measures all of these manifestations for a comprehensive evaluation of EVA. Existing devices that individually measure one of these parameters are expensive, require a dedicated expert, non-scalable, and not suitable for routine clinical use. Ultrasound imaging involved in a majority of these measurement procedures is subject to legal constraints in India, inhibiting their field deployment.


Addressing these limitations, in this work, we have developed and validated image-free ultrasound methods for the measurement of arterial structural properties, functional and incremental elastic properties, endothelial function, and central blood pressure for the comprehensive evaluation of early vascular aging. One important segment of the work, automated assessment of arterial structural properties, will be presented in this talk. The measurement framework involves automatic arterial wall recognition, wall motion tracking, and delineation of arterial wall layers' boundaries. As for the framework's first two tasks, we have developed a dynamic time warping-based method to recognize the arterial walls and track their motion robustly. Further, for the latter task, we have developed an analytic phase-based method that delineates the arterial wall layers from the captured one-dimensional ultrasound frames to measure the instantaneous lumen diameter and a surrogate of wall thickness in real-time. The methods' performance was thoroughly demonstrated via systematic simulations, controlled phantom experiments, and in-vivo human trials on 40 subjects. The recognition and tracking method demonstrated a sensitivity ≥ 94%, precision ≥ 98%, specificity ≥ 98%, and RMSE 2 μm. Likewise, the diameter and surrogate wall thickness measures were evaluated with RMSE smaller than 0.3 mm and 40 μm, respectively.