| 摘要 |
In a present invention the physiology of a vessel wall is investigated using the frequency shifting of an oscillator (21) due to capacitance variations of a capacitor formed between a metallic plate (12) carried by a catheter (10) and an adjacent section of the vessel wall in which the catheter (10) is inserted. Changes in capacitance presented by this variable are detected by the frequency shifting of an associated variable frequency oscillator (21) which is mixed with the output of a fixed frequency oscillator (23). |
