With respect to preventive and primordial care against cardiovascular diseases, clinical community has been emphasizing the pressing need to assess ‘Vascular Ageing’ (VA), a continual degradation of vascular structure and function across one’s life course. Though, it has been increasingly recognized that measuring the key arterial markers – wall geometry, regional and local stiffness, and central blood pressure (CBP) alongside is pivotal to understanding and monitoring early VA, there is a lack of a single device that features such a measurement of coalescence of markers. From an instrumentation perspective, that implies multiple devices, tedious measurement procedures, the requirement of varied technical expertise, more time, and more cost. Also, there are inherent unsolved technological limitations and challenges associated with measuring a subset of these parameters.

Addressing this gap, in this work, we have developed automated A-mode ultrasound-based methods for multifaceted measurement of the artery’s structural and functional properties, catalysing affordable technology for the comprehensive evaluation of early VA. The first important segment of the work includes development of robust and fully automated methods for assessment of arterial structural properties. The measurement framework involves automated 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 studies (cumulatively on more than 150 volunteers).

The developed automated methods for (i) auto-recognition and tracking of vessel walls, and (ii) diameter and wall thickness measurement were the basis for further work on functional properties assessment. In this regard, we presented the development of fast A-mode ultrasound technology and associated novel methods to measure the functional properties of the arteries in real-time, which include (i) regional stiffness (carotid-femoral pulse wave velocity), (ii) local pulse wave velocity, (iii) its beat-to-beat and intra-beat acute changes, and (iv) CBP. The methods are focused on addressing the crucial methodological considerations in-terms of instrumentation and arterial wave-reflections, which hitherto have limited the reliable measurement of these functional properties in literature. The developed A-mode system and methods were first characterised by in-silico and in-vitro experiments, to achieve optimal design. The work then thoroughly validates them via controlled in vitro phantom experiments for accuracy and repeatability, and in vivo trials (on more than 250 subjects) for measurement feasibility.