City Research Online

Abstract

Age-related deterioration of vascular elasticity contributes to cardiovascular disease (CVD), the leading cause of death worldwide, making early detection in primary care essential. This study investigated the feasibility of photoplethysmography (PPG) and laser Doppler flowmetry (LDF) in an in vitro vascular system, examining independent and combined use. Custom femoral vessel–tissue phantoms replicated healthy (0.82 MPa), intermediate (1.48 MPa) and unhealthy (2.06 MPa) arterial stiffness. Two blood-mimicking fluids (BMFs) with scattering agents (intralipid and LPFS) evaluated modality performance. Extracted features included area, slope ratio and datum-based PPG metrics, plus LDF DC mean flux, statistically analysed using the Kruskal–Wallis test. The intralipid-based BMF produced larger reductions in LDF DC flux. Multiclass classification improved prediction when combining signals, yielding 100% holdout accuracy for red and infra-red (IR) PPG and 95.24% for green PPG with intralipid. These findings demonstrate technical feasibility for stiffness discrimination and motivate in vivo validation against clinical markers.

Publication Type:	Article
Additional Information:	© The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Subjects:	R Medicine > R Medicine (General) R Medicine > RC Internal medicine T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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