in-vivo Blood Flow Detection using Diffuse Speckle Contrast Analysis

Abstract

Stable circulation is essential for healthy life. In contrast, circulatory disturbance could cause cardiovascular diseases such as stroke and cardiac death. Recently, statistical data showed that 25 % of cause of death in Korea is related to circulatory system. The blood flow detection in early stage is essential for prevention of the cardiovascular disease. To diagnose these kinds of diseases which is originated from circulatory disturbance, blood flow measurement system requires frequent inspection, non-invasive measurement, and high data acquisition speed. Previous studies on blood flow measurement such as implantable arterial blood flow sensor and ultrasound imaging have been reported. However, these inspection methods are invasive or inefficient. Here, we suggest diffuse speckle contrast analysis (DSCA) system which performs non-invasive estimation for the blood flow, which is dependent on the correlation of speckle pattern caused by the blood flow. DSCA system could offer simple data analysis, flexibility, and fast measurement speed compared to previous studies. Since the DSCA system could achieve 1 Hz data acquisition rate and deep blood flow measurement, in-vivo experiments are available in human skin, chick embryo, erectile dysfunction, and ischemic stroke rat brain. Results show the validation of the DSCA system by various experiments with phantom, human skin, chick embryo, erectile dysfunction, and rat brain. In the phantom experiment, the DSCA system shows almost linear correlation between the blood flow index and the induced Intralipid flow. In the chick embryo experiment, comparative experiment between healthy embryo and weakened embryo prove that DSCA system could detect a vital sign of embryo. The blood flow index of healthy embryo is much higher than weakened embryo. The stroke rat brain experiment shows that infarct area has less blood flow index than contralateral area. Erectile dysfunction and human arm experiments indicate the effectiveness of the measurement system by measuring real-time change of blood flow index caused by stimulation or pressure, respectively. With various data analyses and configurations, the performance of DSCA system was evaluated on various samples and proved effectiveness of the DSCA system for blood flow measurement. From this study, the DSCA system could secure in-vivo measurement of blood flow in deep tissues. In future work, the DSCA system will be useful in medical diagnostic device. ⓒ 2016 DGIST