| 摘要 |
In the present invention, a catheter comprises a resiliently biased projection and a detector which generates a signal which varies as a function of radial displacement of the resiliently biased projection relative to the longitudinal axis of the catheter. In a preferred example, the catheter comprises a resiliently biased projection comprising one plate of a variable capacitor, wherein the capacitance varies as a function of radial displacement of the resiliently biased projection. Thus, a signal processing system electrically coupled to the variable capacitor plate may be adapted to detect changes in the capacitance of the variable capacitor. This affords a method of studying the physiology and/or morphology of a vessel wall by detecting capacitance variations between capacitor plates inserted into the vascular tissue. The present invention allows dimensional characteristics of the vascular tissue to be determined. For example, the cross-section of a vascular lumen can be measured by measuring the capacitance between the plates of the variable capacitor and relating this to the distance between the plates. If the position of one of the plates in the lumen is known, for example, being positioned against one wall of the vessel, the resiliently biased projection, comprising the other plate of the variable capacitor, can bias itself against the opposing wall. The measured capacitance is directly proportional to the distance between the plates.
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