# US 8,784,332 B2 · System for transcutaneous monitoring of intracranial pressure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,332 B2 - Document ID: US8784332B2 - Status: Granted - Kind: B2 - Application number: 13/645,358 - Filed: 2012-10-04 - Published: 2013-02-07 - Granted: 2014-07-22 - Earliest claimed: 2005-02-24 - Applicants: Erich W. Wolf, II - Inventors: Erich W. Wolf, II - Web page: https://patentgrep.com/patent/US8784332B2 ## CPC - A61B 5/0077: {Devices for viewing the surface of the body, e.g. camera, magnifying lens} - A61B 5/0017: {transmitting optical signals} - A61B 5/0031: {Implanted circuitry} - A61B 5/0086: {using infrared radiation} - A61B 5/031: {Intracranial pressure} - A61B 5/0075: {by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy (A61B5/0071 takes precedence)} - A61B 2560/0219: of externally powered implanted units - A61B 2562/0247: Pressure sensors - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A system for measuring and converting to an observer intelligible form an internal physiological parameter of a patient. The invention allows transcutaneous telemetry of intracranial pressure via a system which includes a patient implanted sensor module and an external processing module, optically coupled to the sensor module via an external coupling module. A sensor within the sensor module transduces the measured pressure and a near infrared emitter transmits the telemetry when interrogated by the external coupling module. A set of tuned inductor-crystal circuits comprised in part of a cylindrical crystal oscillator whose resonant frequency is sensed by a dipper circuit arrangement is provided. Power for the sensor module is derived inductively through rectification of a transcutaneously-applied high-frequency alternating electromagnetic field generated within the external coupling module. A computer within the processing module calculates the physiological parameter from the telemetry signal and represents this data in numerical, graphical, or analog format. ## Claims ### Claim 1 A method of determining an intracranial fluid pressure of an intracranial fluid comprising the steps of: providing a cylindrical crystal oscillator probe having a transducer crystal and a reference crystal, wherein the transducer crystal is in contact with the intracranial fluid; providing at least one driver circuit within the cylindrical crystal oscillator probe connected to the transducer crystal and the reference crystal; exposing the reference crystal to a reference pressure; exposing the transducer crystal to the intracranial fluid pressure; exciting the transducer crystal to provide a first radio frequency energy absorption; exciting the reference crystal to produce a second radio frequency energy absorption; measuring the first radio frequency energy absorption; measuring the second radio frequency energy absorption; comparing the first radio frequency energy absorption and the second radio frequency energy absorption to determine a difference; determining the intracranial fluid pressure from the difference and the reference pressure; determining a first resonance frequency from the first radio frequency absorption; determining a second resonance frequency from the second radio frequency absorption; determining a calibration slope linearly relating a set of absorption frequencies to a set of pressures; wherein the step of determining the intracranial fluid pressure includes application of the formula: P=P0−m(f0−f1) where: P=the intracranial fluid pressure; P0=the reference pressure; m=the calibration slope; f0=the first resonant frequency; and, f1=the second resonant frequency. ### Claim 2 (depends on 1) The method of claim 1 wherein the steps of exciting the transducer crystal and exciting the reference crystal include the steps of: providing a first coil connected to the reference crystal; providing a second coil connected to the transducer crystal; and, sweeping an oscillating electromagnetic field over the first coil and the second coil to produce at least one frequency absorption null. ### Claim 3 (depends on 1) The method of claim 1 including the further steps of: providing a memory in the crystal oscillator probe; and, storing a set of calibration data in the memory. ### Claim 4 (depends on 1) The method of claim 1 including the further steps of: providing a memory in the crystal oscillator probe; and, storing a set of patient data in the memory. ### Claim 5 (depends on 1) The method of claim 1 wherein the step of measuring the first radio frequency energy absorption further comprises the step of accounting for a protein deposit from the intracranial fluid. ### Claim 6 (depends on 5) The method of claim 5 wherein the step of accounting for a protein deposit further includes the step of: determining a reported resonant frequency fr according to the formula: fr=fmeasured+(fi−ft) where: fr=the reported resonant frequency; fmeasured=the first resonant frequency; fi=an initial resonant frequency; and, ft=a final resonant frequency. ### Claim 7 (depends on 6) The method of claim 6 further including the step of: recording the initial resonant frequency and a time of inception. ### Claim 8 A method of determining an intracranial fluid pressure of an intracranial fluid comprising the steps of: providing a cylindrical crystal oscillator probe having a transducer section and a reference section; providing at least one driver circuit within the cylindrical crystal oscillator probe connected to the transducer section and the reference section; exposing the reference section to a reference pressure; exposing the transducer section to the intracranial fluid pressure; exciting the transducer section to provide a first radio frequency energy absorption; exciting the reference section to produce a second radio frequency energy absorption; measuring the first radio frequency energy absorption; measuring the second radio frequency energy absorption; comparing the first radio frequency energy absorption and the second radio frequency energy absorption to determine a difference; determining the intracranial fluid pressure from the difference and the reference pressure; determining a first resonance frequency from the first radio frequency absorption; determining a second resonance frequency from the second radio frequency absorption; determining a calibration slope linearly relating a set of absorption frequencies to a set of pressures; and, wherein the step of determining the intracranial fluid pressure includes application of the formula: P=P0−m(f0−f1) where: P=the intracranial fluid pressure; P0=the reference pressure; m=the calibration slope; f0=the first resonant frequency; and, f1=the second resonant frequency. ### Claim 9 A method of determining an intracranial fluid pressure of an intracranial fluid comprising the steps of: providing a cylindrical crystal oscillator probe having a transducer section and a reference section; providing at least one driver circuit within the cylindrical crystal oscillator probe connected to the transducer section and the reference section; exposing the reference section to a reference pressure; exposing the transducer section to the intracranial fluid pressure; exciting the transducer section to provide a first radio frequency energy absorption; exciting the reference section to produce a second radio frequency energy absorption; measuring the first radio frequency energy absorption; measuring the second radio frequency energy absorption; comparing the first radio frequency energy absorption and the second radio frequency energy absorption to determine a difference; determining the intracranial fluid pressure from the difference and the reference pressure; determining a first resonance frequency from the first radio frequency absorption; determining a second resonance frequency from the second radio frequency absorption; determining a calibration slope linearly relating a set of absorption frequencies to a set of pressures; wherein the step of determining the intracranial fluid pressure includes application of the formula: P=P0−m(f0−f1) where: P=the intracranial fluid pressure; P0=the reference pressure; m=the calibration slope; f0=the first resonant frequency; f1=the second resonant frequency; providing a first coil connected to the reference section; providing a second coil connected to the transducer section; and, sweeping an oscillating electromagnetic field over the first coil and the second coil to produce at least one frequency absorption null. ### Claim 10 A method of determining an intracranial fluid pressure of an intracranial fluid comprising the steps of: providing a cylindrical crystal oscillator probe having a transducer section and a reference section; providing at least one driver circuit within the cylindrical crystal oscillator probe connected to the transducer section and the reference section; exposing the reference section to a reference pressure; exposing the transducer section to the intracranial fluid pressure; exciting the transducer section to provide a first radio frequency energy absorption; exciting the reference section to produce a second radio frequency energy absorption; measuring the first radio frequency energy absorption; measuring the second radio frequency energy absorption; comparing the first radio frequency energy absorption and the second radio frequency energy absorption to determine a difference; determining the intracranial fluid pressure from the difference and the reference pressure; and, wherein the step of measuring the first radio frequency energy absorption further comprises the step of accounting for a protein deposit from the intracranial fluid. ### Claim 11 A method of determining an intracranial fluid pressure of an intracranial fluid comprising the steps of: providing a cylindrical crystal oscillator probe having a transducer section and a reference section; providing at least one driver circuit within the cylindrical crystal oscillator probe connected to the transducer section and the reference section; exposing the reference section to a reference pressure; exposing the transducer section to the intracranial fluid pressure; exciting the transducer section to provide a first radio frequency energy absorption; exciting the reference section to produce a second radio frequency energy absorption; measuring the first radio frequency energy absorption; measuring the second radio frequency energy absorption; comparing the first radio frequency energy absorption and the second radio frequency energy absorption to determine a difference; determining the intracranial fluid pressure from the difference and the reference pressure; wherein the step of measuring the first radio frequency energy absorption further comprises the step of accounting for a protein deposit from the intracranial fluid; and, wherein the step of accounting for a protein deposit further includes the step of: determining a reported resonant frequency fr according to the formula: fr=fmeasured+(fi−ft) where: fr=the reported resonant frequency; fmeasured=a first resonant frequency; fi=an initial resonant frequency; and, ft=a final resonant frequency. ### Claim 12 A method of determining an intracranial fluid pressure of an intracranial fluid comprising the steps of: providing a cylindrical crystal oscillator probe having a transducer section and a reference section; providing at least one driver circuit within the cylindrical crystal oscillator probe connected to the transducer section and the reference section; exposing the reference section to a reference pressure; exposing the transducer section to the intracranial fluid pressure; exciting the transducer section to provide a first radio frequency energy absorption; exciting the reference section to produce a second radio frequency energy absorption; measuring the first radio frequency energy absorption; measuring the second radio frequency energy absorption; comparing the first radio frequency energy absorption and the second radio frequency energy absorption to determine a difference; and, determining the intracranial fluid pressure from the difference and the reference pressure; wherein the step of measuring the first radio frequency energy absorption further comprises the step of accounting for a protein deposit from the intracranial fluid; wherein the step of accounting for a protein deposit further includes the step of: determining a reported resonant frequency fr according to the formula: fr=fmeasured+(fi−ft) where: fr=the reported resonant frequency; fmeasured=a first resonant frequency; fi=an initial resonant frequency; ft=a final resonant frequency; and, further including the step of recording the initial resonant frequency and a time of inception.