Non-invasive detection of structures in conduit - by externally measuring streaming potentials generated by flowing fluid using two electrodes

摘要

The location of a constriction of an ionically conductive vessel, e.g. an artery, through which a conductive fluid, e.g. blood, is flowing is detected by sensing the streaming potential at locations spaced along the vessel. The detected streaming potentials are compared and the detected streaming potential having the highest relative magnitude is selected, the constriction being located with reference to where the highest streaming potential was detected. The streaming potentials are detected by a sensor (50) comprising two passive electrodes (64), the spacing (L) between them being variable.