| Author: | Zhao, Liangjing |
| Title: | Variation of spectral characteristic vasomotion at different locations |
| Advisors: | Tang, Hui (ME) Liu, Yang (ME) |
| Degree: | Ph.D. |
| Year: | 2024 |
| Subject: | Vasomotor system Blood-vessels Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering |
| Pages: | xii, 127 pages : color illustrations |
| Language: | English |
| Abstract: | Vasomotion, which refers to the spontaneous oscillation of blood vessels within the frequency band of 0.0095-1.6Hz, remains an area of interest due to the limited understanding of its physiological mechanisms in diabetes and hypertension. This study utilized a laser Doppler flowmeter to investigate vasomotion at four acupoints (Jingqu-LU8, Quze-PC3, Sanyinjiao-SP6, and Chize-LU5) among four distinct groups, each comprising 49 subjects. These groups include the diabetes group (Group D), hypertension group (Group H), patients with both diabetes and hypertension (Group D+H), and a healthy control group (Group C). The thesis encompasses three primary aspects: the variation of spectral analysis on vasomotion, the influence of diabetes and hypertension on vasomotion, and the specificity of acupoints in reflecting vasomotion. The first segment of this thesis focuses on exploring the impact of diabetes and hypertension on vasomotion within five distinct frequency bands (0.0095-0.02, 0.02-0.06, 0.06-0.15, 0.15-0.4, and 0.4-1.6Hz). The study compares the relative energy contribution (REC) among groups and measurement locations to understand the effects. Additionally, the study examines the influence of the duration of diabetes and hypertension on vasomotion. Subgroups within Group D+H are formed based on the duration of their conditions, revealing the potential dominance of vasomotor activities in specific measurement locations by the duration of diabetes or hypertension. The second topic of this thesis explores Stochastic Resonance (SR) in vasomotion, which is characterized by a sharp increase, peak, and gradual decline in the Signal-to-Noise Ratio (SNR) at specific noise levels. By calculating the noise type of different groups, the study determines the impact of diabetes and hypertension on the overall noise level of all frequency bands for vasomotion. The study observes significantly different noise types in patients with diabetes and/or hypertension at LU-8 compared to healthy individuals. Furthermore, the study decomposes signals into four frequency domains (0.0095-0.06, 0.06-0.15, 0.15-0.4, and 0.4-1.6Hz) using Hilbert-Huang Transform (HHT), and compares SNR between groups in different frequency bands. The phenomenon of SR is observed through instantaneous noise and SNR by HHT in all groups and measurement locations across all frequency domains. The third aspect of this thesis focuses on the specificity of acupoints in reflecting vasomotion, which is discussed throughout all sections. The study’s results of REC, noise type, and SNR demonstrate the strong specificity of acupoints, highlighting the anisotropy of vasomotion among vessels. In conclusion, this comprehensive study sheds light on the intricate relationships between vasomotion, diabetes, hypertension, and acupoints, contributing to the understanding of vascular dynamics and its potential implications for clinical management. |
| Rights: | All rights reserved |
| Access: | open access |
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