Apparatus for recording intracranial pressure

• US 4,971,061 A
• Filed: 05/11/1989
• Issued: 11/20/1990
• Est. Priority Date: 09/27/1986
• Status: Expired due to Fees

• Current Assignee: Hiroji Kuchiwaki, Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hiroji Kuchiwaki, Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Minamiyama, Eiji, Kuchiwaki, Hiroji, Ito, Junki, Kageyama, Naoki, Ogura, Yukio, Sakuma, Nobumitsu
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US07/350,704
• Time in Patent Office: 558 Days
• Field of Search: 128/660.02, 128/662.03, 128/748
• US Class Current: 600/438
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61B 8/0808 for diagnosis of the brain

Abstract

An apparatus for recording the intracranial pressure of a living body or patient utilizing ultrasonic waves includes a probe which is connected to a pulser to receive intracranial echoes that are multi-reflected being interfered with each other, a receiver for amplifying the received echoes, a gate circuit which applies a gate for a predetermined time duration of echo synchronous with the heart beat among the amplified echoes and which produces internal waves of gates, and a recorder for continuously recording peak values of the output waveforms. The intracranial pressure waveforms are continuously recorded, a change in thickness of the dura mater is found from the recorded intracranial pressure waveforms and a change of the intracranial pressure is found by utilizing a correlation between the intracranial pressure and the thickness of the dura mater.

Claims

1. An apparatus for recording peak values of the sound pressure of reflected ultrasonic waves which correspond to an intracranial pressure of a patient, comprising:

a pulser for generating a voltage pulse;

a probe for receiving said voltage pulse from said pulser and for transmitting an ultrasonic wave pulse into a cranium of the patient and for receiving reflected ultrasonic waves from inside of said cranium, said ultrasonic wave pulse being transmitted in accordance with said voltage pulse;

a receiver connected to said pulser for amplifying the sound pressure of said reflected ultrasonic waves received by said probe and for providing output waveforms corresponding thereto;

a gate circuit, connected to said receiver, for setting a gate within a required range of said output waveforms from said receiver;

a peak detector connected to an output of said gate circuit, for detecting peak values of the sound pressure within the gate width set by said gate circuit by detecting peak values of said output waveforms from said receiver as gated by said gate circuit; and

a recorder for continuously recording said detected peak values;

wherein said probe transmits an ultrasonic wave having a pulse train length which is more than twice as large as a thickness of dura mater inside said cranium, and wherein said gate circuit is so arranged as to set its gate to a time duration corresponding to the time in which reflection waves from said dura mater occur.