使用多模光纤导管进行体内多普勒频移测量。

In vivo Doppler shift measurements using multimode fiber-optic catheters.

作者信息

Tjin S C, Ng S L, Soo K T

机构信息

School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore.

出版信息

IEEE Trans Biomed Eng. 1998 Oct;45(10):1272-8. doi: 10.1109/10.720205.

DOI:10.1109/10.720205

PMID:9775541

Abstract

A new fiber-optic catheter for in vivo blood-flow measurements has been developed. The catheter is designed to measure blood flow in both the forward (toward the catheter tip) and reverse (away from the catheter tip) flow directions. It consists of two multimode optical fibers with core diameter of 50 microns and cladding diameter of 125 microns. One fiber transmits the laser beam into blood and the other receives the backscattered light from the erythrocytes within the probe volume. In the flow experiment, it was found that the flow within the boundary layer is indeed laminar and, hence, the relationship between the Doppler shift frequencies and the flow velocities is linear, thereby making the linear calibration possible for predicting the free stream flow velocity. Plots of the maximum shift frequency (frequency at which the Doppler spectrum disappeared into the noise spectrum) against the flow velocities are found to be more linear in both the forward and reverse flow directions than that of the dominant shift frequency (frequency with the highest amplitude). These results were reaffirmed by the numerical flow simulation along the catheter side wall.

摘要

一种用于体内血流测量的新型光纤导管已被研发出来。该导管旨在测量正向（朝向导管尖端）和反向（远离导管尖端）血流方向的血流。它由两根芯径为50微米、包层直径为125微米的多模光纤组成。一根光纤将激光束传输到血液中，另一根接收来自探头体积内红细胞的后向散射光。在流动实验中，发现边界层内的流动确实是层流，因此，多普勒频移频率与流速之间的关系是线性的，从而使得预测自由流流速的线性校准成为可能。与主导频移频率（幅度最高的频率）相比，在正向和反向流动方向上，最大频移频率（多普勒频谱消失在噪声频谱中的频率）与流速的关系图都更呈线性。沿导管侧壁的数值流动模拟再次证实了这些结果。