Electrical method and apparatus for non-invasively detecting abnormal

Abstract

Method and apparatus are disclosed for obtaining flow information of a conductive fluid by detecting the streaming potential and analyzing the resultant signal. In a particular embodiment for detecting abnormal blood velocities in the arterial tree, the apparatus includes a flexible sensor having two fixedly spaced apart electrodes and a common mode signal electrode. Each sensor electrode is connected to an input of a differential amplifier and the common electrode is connected to the common input of the differential amplifier. The output signal from the differential amplifier, after filtering and amplification is provided to a recorder or oscilloscope so that it can be compared with the normal or average signal. A particular embodiment of the method is used to detect blood flow abnormalities, either too fast or too slow compared with most healthy individuals of the same age. In this method, a flexible sensor having two fixedly mounted electrodes is placed on the skin over the artery to be examined, for example the dorsalis pedis artery, so that each electrode is in electrical contact with a different part of the artery. The detected signal is processed and is compared to normal signals. These comparisons can be the wave shape or the time difference between the detection of the wave pulse and a pump timing signal such as the ECG signal.