Non-invasive method for measuring local pulse wave velocity in arteries: part II

A NOVEL METHOD FOR DETERMINING THE ARRIVAL TIME OF REFLECTED WAVE AT SINGLE SITE: VALIDATION USING PHASE CONTRAST MAGNETIC RESONANCE DATA

Characterization of the wave reflection and mainly its return time has significant clinical value in detecting cardiovascular and cerebrovascular diseases. Indeed, the return time is an indicator which is used to evaluate the performance of peripheral perfusion and the propagation speed for arterial stiffness measurement. The study is aimed at implementing a novel model based on cepstral analysis for estimation of the arrival time of reflected wave ([Formula: see text]. The proposed method is specially based on cepstral analysis of the simulated blood velocity wave by using the Matlab software. To achieve this aim, we used a theoretical bidimensional model to simulate blood flow velocity, and we combined this model with clinical data acquired in two healthy subjects using phase contrast magnetic resonance imaging (PCMRI). Values of the arrival time of reflected wave measured are similar to the theoretical values. The suggested model is validated in vivo. We can conclude that the novel approach described in this paper offers a promising efficient and convenient method to determinate noninvasively arrival time of reflected wave.

A novel non-invasive method for estimating the local wave speed at a single site in the internal carotid artery

Objectives Local wave speed is a biomarker which provides an objective analysis of the cardiovascular function. The aim of this study was to determine the local wave speed in the internal carotid artery by a new non-invasive method that measures blood velocity waveform at only one site. Methods For this purpose, the cepstral analysis was employed to determine the arrival time of the reflection wave and the wave speed in the carotid artery. To validate our model, we applied it experimentally in vivo on young and old healthy subjects. The blood velocity waveform was measured by using phase-contrast magnetic resonance for 22 subjects. Results Our experimental results correlated with reference values reported in previous studies conducted on the internal arterial carotid usually adopting the invasive method. They also correlated with those obtained by using the foot-to-foot method (R2=0.72). The wave speed obtained by the method developed in this study and that of the foot-to-foot method increased with age (p<0.001). Conclusions The method developed in this study can be applied in the other arteries and it can also be used with other techniques such as ultrasound imaging.