Design and thermal modeling of a non-invasive probe for measuring perfusion by thermodiffusion

摘要

This research 1) explores the feasibility of developing a non-invasive probe to precisely quantify microcirculatory blood flow (tissue perfusion), in real time and in absolute units, and 2) presents designs and models of such a probe, along with an evaluation of various design-model combinations. Bowman et al. have developed an invasive thermodiffusion probe that measures tissue perfusion accurately, continuously, and in real time. This method employs a self-heated thermistor placed in perfused tissue. From a knowledge of the power required to heat the thermistor probe to a given temperature, perfusion can be calculated using an analytical or numerical model. Using Bowman's thermodiffusion probe (designed for invasive use) in a non-invasive manner, a perfusion study was performed. The data clearly show the promise of a non-invasive thermodiffusion perfusion probe (designed for non-invasive use), and the design of such a probe was pursued by adapting the invasive technology for a non-invasive probe. Because perfusion is not actually measured but calculated from measured quantities by a model of the probe and perfused tissue, the design of the non-invasive probe occurred hand-in-hand with the development of analytical models.