Water content probe
US6950699B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 2001 |
| Grant date | Sep 27, 2005 |
| Priority date | — |
| Expiry date | Jan 7, 2024 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/6864
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A method and system to determine brain stiffness is disclosed. A probe to measure tissue water content is inserted through an aperture (burr hole) in the cranium into brain tissue. The probe has two electrically separated plate conductors with a dielectric which forms a capacitor plane. One conductor has a surface mount resistor to allow exact impedance matching to the core of a coaxial cable. The other conductor attaches electrically to the shield of the coaxial cable. The probe is stabilized in the brain tissue through a plastic ventriculostomy bolt which has been secured by screw tapping into the cranium. The coaxial cable connects to a spectrum analyzer. Brain water content and blood congestion alter the resonant frequency of the probe, allowing a realtime readout of apparent tissue water content. By monitoring the momentary shift in center resonant frequency or, alternatively, the standing wave ratio slightly off resonant frequency, a beat-to-beat pulsatile waveform is derived relating to the perfusion of the brain. A strain gauge intracranial pressure sensor (ICP) is separately affixed through the bolt and adjacent to the water content probe. By comparing the phase angle or l…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.