Analysis Of The Dynamics Of Vasomotion Using Laser Doppler Flow

Abstract

Vasomotion is a phenomenon caused by changes in the diameters of blood vessels. It is due to the contractile activity of small arteries and arterioles resulting in periodic changes of blood flow in the skin. These flow variations in the arteries are reflected by the Laser Doppler Flowmeter. The goal of the skin blood flow (blood perfusion) study is to establish a method to analyze and quantify the pattern of vasomotion as detected using Laser Doppler Flow (LDF). Spectral analysis of the LDF signal reveals the presence of periodic components in the vascular system. The study involves twelve subjects of which six subjects are normal and six subjects have a history of vascular diseases. Peaks occurring between frequencies 0 Hz - 0.2 Hz are isolated from the power spectrum and various prime number series are generated. The skew of the series is significantly different for normal and diseased subjects (α = 0.05) and examination of peak height as a function of frequency (odds ratio = 4) is a distinguishing factor for the two subject populations. The high level of order and structure seen in the microvasculature is elucidated by way of phase plane analysis and singular value decomposition (SVD). Normal subjects exhibit dynamic phase plots while diseased subjects have lesser complicated patterns. Statistical testing of the singular values shows significant differences between the two groups (F-test and Mann - Whitney test at α = 0.05) suggesting the loss or change of one or more physiologic components in the vascular system of the diseased subjects.