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Seminar 1 Near-infrared optical imaging for clinical applications and Seminar 2 Formation Mechanism of Blood Pulse Profiles( 2:00 p.m. , Friday, October 16, 2015)
发表时间:2015-10-14 阅读次数:297次

Time:    2 p.m., Friday, October 16

Venue:  Room 1801, East Guanghua Building, Handan Campus, Fudan University

 

Seminar 1  

Speaker: Chia-Wei Sun  

                   Assistant Professor

                  Department of Photonics, National Chiao Tung University, Taiwan

Title:        Near-infrared optical imaging for clinical applications

Abstract:

Recently, noninvasive evaluation of activation-related tissue oxygenation changes has become available with near-infrared spectroscopy (NIRS). Since the NIRS method can evaluate the spatial distribution of tissue oxygenation in real-time, it has been proposed as an effective tool to quantify changes of local oxygenation in muscle tissue. In order to avoid the use of an exogenous tracer, the analysis of the dynamic response to oxy-hemoglobin (HbO2) and deoxy-hemoglobin (Hb) during a standardized vascular occlusion test has been proposed for characterizing local metabolic rate, i.e., to analyze the concomitant temporal response of NIRS signal with applied vascular occlusion. Also, the tissue oxygen saturation (StO2) and total hemoglobin (tHb) changes can be assessed by use of NIRS technique as markers of oxygen consumption and cardiovascular reserve with resting and exercising test. The high sensitivity of NIRS to changes in the tissue hemoglobin concentration (changes as small as 0.05-0.10 µM in tissues can be detected) affords the optical detection of small cerebral hemodynamic fluctuations. NIRS is a promising non-invasive brain imaging technique with a high sampling rate, precise and localized spatial resolution. Neurovascular coupling is the generic term for changes in cerebral metabolic rate of oxygen (CMRO2), cerebral blood flow (CBF), and cerebral blood volume (CBV) related to brain activity. NIRS detects changes in [HbO2] and [Hb] and therefore total hemoglobin concentration [tHb], which corresponds to CBV. CBF and CMRO2also affect the [HbO2] and [Hb] traces. Assuming a one-compartment model (Fig. 4.2), an isolated change in CBF will have the depicted effect on the [HbO2] and [Hb]. The increase in CBF will lead to an increase in [HbO2] and a decrease in [Hb] because more oxygenated than deoxygenated blood will fill the compartment. This effect is often described as the washout effect. Note that the changes are completely symmetrical. This NIRS method permitted several benefits as non-invasive, less expensive, non-ionizing radiation imaging, real-time measurement, compact implementation, long time monitoring and easy operation with high time resolution and adequate spatial resolution for continuously recording [HbO2] and [Hb] changes of brain. Also, NIRS offers a more comprehensive measurement of brain activity than blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI).

 

Seminar 2

Speaker: Dan Hu  

                 Distinguished Research Fellow

                 Institute of Natural Sciences and Department of Mathematics, Shanghai Jiao Tong University

Title:        Formation Mechanism of Blood Pulse Profiles

Abstract:

In traditional Chinese and Greek medicine, blood pulse phase is believed to be an important indicator of the state of human body. Strong correlations between diseases and the types of blood pulse profiles, such as hypertension and wiry pulse, have been discovered in medical measurements. In this work, one‐dimensional model of the interaction between blood flow and blood vessel walls is used to describe the propagation of blood pulse waves in arterial trees. The formation mechanisms of important characteristics of blood pulse profiles, such as the dicrotic wave and the predicrotic wave, are explained in detail by the propagation of blood pulse waves. Consistent with medical observations, our numerical study shows that vessel thickening as a result of hypertension lead to the formation of wiry pulse. These results suggest that the change of the arterial tree structure in patients can lead to significant change in blood pulse phase, thus providing useful information in medical diagnosis.

 

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