WO1996025876A1 - Subarachnoidal space monitoring system - Google Patents
Subarachnoidal space monitoring system Download PDFInfo
- Publication number
- WO1996025876A1 WO1996025876A1 PCT/PL1995/000018 PL9500018W WO9625876A1 WO 1996025876 A1 WO1996025876 A1 WO 1996025876A1 PL 9500018 W PL9500018 W PL 9500018W WO 9625876 A1 WO9625876 A1 WO 9625876A1
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- WO
- WIPO (PCT)
- Prior art keywords
- pass filter
- input
- low
- photodiode
- brain
- Prior art date
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
- A61B5/1073—Measuring volume, e.g. of limbs
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
- A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
- A61B5/14553—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases specially adapted for cerebral tissue
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Medical Informatics (AREA)
- Surgery (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Veterinary Medicine (AREA)
- Molecular Biology (AREA)
- Public Health (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Dentistry (AREA)
- Neurology (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Optics & Photonics (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
- Measuring And Recording Apparatus For Diagnosis (AREA)
Abstract
A system, for monitoring the changes in the volume of the protective subarachnoidal space surrounding the outside of the brain and the changes in the pulsation of this space inside the skull comprises an eletroluminescent diode (1) emitting pulsating infrared light beams in the range of 650-950 nm in the direction of an examined subject (2). The incident light beams going through the skin layer (a), the cranial bones (b), the cerebrospinal fluid (c) and the brain (d) is received in proximity to the emitting diode by a photodiode (3), and at the distance from the emitting diode by a photodiode (4), whose outputs are connected through amplifiers (5, 11), low-pass filter systems (6, 12), low-pass filters (7, 14) and high-pass filters (8, 13) to an analog-to-digital converter (9). The output of the converter is connected with the input of a computer (10).
Description
SUBARACHNOIDAL SPACE MONITORING SYSTEM
Subarachnoidal space monitoring system has its application in non-invasive monitoring of the changes in the human or animal brain's blood supply as well as the brain's volume.
The fluid transducer of the intracranial pressure,
disclosed in the Polish description of the patent No.
PL-P-131236, consists of a mechanical sensor screwed into the
cranial bone at the examined place.
The drawback of the transducer is that during the very
measurement the continuity of the cranial bone is
mechanically broken.
Non-invasive monitoring of blood flow and blood pressure
in the brain with the application of the ultraminiature
sensor of the photoelectric-plethysmographic type, which
records the light emitted and reflected at the supraorbital
part of the forehead, is disclosed in the European description
of the patent No, EP-A-0276344. The disclosed sensor consists
of the li ht source and the dectector placed at a defined
angle in relation to the external surface of the skull. The
light source emitting the light beam is placed at a small
angle, whereas the detector is located at a larger angle s
that the axes of the beams intersect on the examined subjec
in the form of the extracranial artery. The light reflected
from the extracranial vessels is recorded with the
osci 1 loscope.
The drawback of the disclosed device is that th
measurement requires monitoring of the blood flow in th
arterial vessel outside the cranial bone.
Optical oximeter measuring oxygen in the brain is
disclosed in the world patent No, W0-92/21283. This
device consists of a infrared light source and two detector
located on the external surface of the skull. The li h
source emits a light beam that passes through the bone an
the forehead part of the brain. The light is absorbed selectively by the brain tissue and vessels, depending on th
degree of oxidation of the blood. Having passed all th
layers of the brain, the cranial bones the light is recorde
by the detectors, and then undergoes further compute
processing.
The drawback of the invention is the lack of possibilit
of monitoring the changes in the brain's volume. Th
disclosed device cannot be applied in measuring the change
of the cerebral blood flow volume.
In order to eliminate the above drawbacks, the following
invention has been prepared. The present invention is
characterized in that the pulsating infrared light beams in
the range of 650-950 nm are emitted from the
electroluminescent diode in the direction of the examined
subject. The incident light beam, passing through the skin
layer, the cranial bones and the cerebrospinal fluid
surrounding the brain as well as through the layer of brain
tissue, is received at the input of the photodiode located
near the electroluminescent diode. The output of the
electrolu inescent diode is connected with the input of the
amplifier, whose output is connected with the input of the
low-pass filter. The outpXit of the low-pass filter is
connected in parallel to the inputs of the low-pass filter
and the high-pass filter, whose outputs are connected with
the inputs of the analog-to-digi al converter. At the other
place distant from the electroluminescent diode, the light
beam falling upon the skin layer, the cranial bones and the
cerebrospinal fluid surrounding the brain is received at the
input of the photodiode, whose output is connected with the
input of the amplifier. The output of the amplifier is
connected with the input of the low-pass fi lter. The output
of the low-pass filter is connected in parallel to the inputs
of the low-pass filter and the high-pass filter. The outpu
of the low-pass filter and the high-pass filter are connect
with the inputs of the analog-to-digital converter, who
output is connected with the input of the computer, where t
signal from the photodiode placed at the distance from t
emitting diode is divided by the signal from the photodio
located in proximity to the emitting diode and undergo
further digital processing.
The advantages of the present invention are its simpl
structure and relatively simple technology of construction
well as direct, non-invasive monitoring of the changes in t
brain's perfusion and volume.
The subject matter of the invention is depicted in
the example of the embodiement, in which Fig. 1 presents a
block diagram of the device, while Fig. 2 presents
cross-section of the examined subject.
The pulsating infrared li ht beams in the range o
650-950 nm are emitted from the electroluminescent diode (1
located on the surface of the forehead part of the head in
the direction of the examined subject (2) that constitutes
protective cerebrospinal fluid (c). The beam passing throu
the skin layer (a), the cranial bones (b) and th
cerebrospinal fluid (c) is partially reflected, diffused
absorbed, transmitted, and is received at the input of the
photodiode (3), placed in proximity to the electroluminescent diode (1), in which the li ht signal is converted into
voltage and passed onto the input of the amplifier (5) with a
digital, adjustable amplification. The signal of cut-off
frequency, preferably 30 Hz, obtained after passing through
the low-pass filter (6), is divided into two components of
the signal, which enter the inputs of the low-pass filter (7)
and the high-pass filter (8), whose outputs are connected
with the inputs of the analog-to-digital converter (9), whose
output is connected with the input of the computer (10),
where the signals from the converter (9) are read in. Leaving
the low-pass filter (7) in the range between 0,0 Hz and
0, 1Hz, the first component of the signal informs of slow
changes in the width of the subarachnoidal space brain-bone.
The other signal componet, leaving the high-pass filter (8)
in the range between 0,1 Hz and 30 Hz, informs of the changes
in the pulsation of this brain space. A different beam
passing through the skin layer (a), the cranial bones (b) and
mainly through the cerebrospinal fluid (c) and the brain
surface (d) is partially reflected, diffused, absorbed,
transmitted, and is received at the input of the photodiode
(4), located at the distance from the electroluminescent
diode (1), which records and converts the light signal int
voltage that is then passed onto the input of the amplifie
(11) with a digitally adjustable amplification. The signal o
cut-off frequency, preferably 30 Hz, obtained after passing
through the low-pass filter (12), is divided into tw
components of the signal, which enter the inputs of th
low-pass filter (14) and the high-pass filter (13), whos
outputs are connected with the inputs of th
analog-to-digital converter (9), whose output is connected
with the input of the computer (10), where the signals fro
the converter (9) are read in. Leaving the low-pass filte
(7) in the range between 0,0 Hz and 0,1 Hz, the firs
component of the signal informs of slow changes in the widt
of the subarachnoidal space brain-bone. The other signal
componet, leaving the high-pass filter (8) in the rang
between 0,1 Hz and 30 Hz, informs of the changes in th
pulsation of this brain space.
The pulsating infrared light beams in the range o
650-950 nm are emitted from the electroluminescent diode (1
located on the surface of the forehead part of the head i
the direction of the examined subject (2) that constitutes
protective cerebrospinal fluid (c). The beam going throug
the skin layer (a), the cranial bones (b) and th
cerebrospinal fluid (c) is partially reflected, diffused,
absorbed, transmitted, and is received at the input of the
photodiode (3), placed in proximity to the electroluminescent
diode (1), in which the light signal is converted into
voltage and passed onto the input of the amplifier (5) with a
digital, adjustable amplification. The signal of cut-off
frequency, preferably 30 Hz, obtained after passing through
the low-pass filter (6), is divided into two components of
the signal, which enter the inputs of the low-pass filter (7)
and the high-pass filter (8), whose outputs are connected
with the inputs of the analog-to-digital converter (9), whose
output is connected with the input of the computer (10),
where the signals from the converter (9) are read in. Leaving
the low-pass filter (7) in the range between 0,0 Hz and
0, 1 Hz, the first component of the signal informs of slow
changes in the width of the subarachnoidal space brain-bone.
The other signal componet, leaving the high-pass filter (8)
in the range between 0,1 Hz and 30 Hz, informs of the changes
in the pulsation of this brain space. A different beam passing
through the skin layer (a), the cranial bones (b) and mainly
through the cerebrospinal fluid (c) and the brain surface
(d) is partially reflected, diffused, absorbed, transmitted,
and is received at the input of the photodiode (4), located
at the distance from the electroluminescent diode (1), which
records and converts the light signal into voltage that is
then passed onto the input of the amplifier (11) with a
digitally adjustable amplification. The signal of cut-off
frequency, preferably 30 Hz, obtained after passing through
the low-pass filter (12), is divided into two components of
the signal, which enter the inputs of the low-pass filter
(14) and the high-pass filter (13), whose outputs are
connected with the inputs of the analog-to-digital conver-
ter (9), whose output is connected with the input of the
computer (10), where the signals from the converter (9) are
read in. Leaving the low-pass filter (7) in the range between
0,0 Hz and 0, 1 Hz, the first component of the signal informs
of slow changes in the width of the subarachnoida 1 space
brain-bone. The other signal co ponet, leaving the high-pass
filter (8) in the range between 0, 1 Hz and 30 Hz, informs of
the changes in the pulsation of this brain space. In the
microcomputer the read-in signals coming from the photodiode
(4) located at the distance from the emitting diode (1) are
divided by the signals coming from the photodiode (3) located
near the emitting diode (1). Thus formed quotient of the
signal undergoes further digital processing.
LIST OF ELEMENTS
(1) electroluminescent diode (LED)
(2) examined subject
(3) photodiode
(4) photodiode
(5) ampl i fier
(6) low-pass filter
(7) low-pass filter
(8) high-pass filter
(9) analog-to-di ital converter
(10) computer (PC)
(11 ) ampl i fier
(12) low-pass filter
(13) high-pass filter
(14) low-pass filter
(a) skin layer
(b) cranial bones
(c) cerebrospinal fluid
(d) brain
Claims
CLA I MS
Subarachnoidal space monitoring system, consistin
of a li ht source, a detector and a recorder, i
characterized in that the pulsating infrared 1 ight beams in
the range of 650-950 nm are emitted from th
electroluminescent diode { i_) in the direction of the examine
subject (2_) , and the light beam falling upon the skin laye
(a) . the cranial bones (b ) and the cerebrospinal fluid (c.)
surrounding the brain (d) is received in proximity to the
input of the photodiode (-3J, whose output is connected i
parallel to the input of the amplifier (_5), whose output i
connected with the input of the low-pass filter (6J whos
output is connected in parallel to the inputs of the low-pas
filter (.1) and the high-pass filter [_.) , whose outputs are
connected with the inputs of the analog-to-digital converte
(9), while at the other distant place the light beam fallin
upon the skin layer (a), the cranial bones (b and the
cerebrospinal fluid (cj surrounding the brain (jd) is
received in proximity to the input of the photodiode (4),
whose output is connected with the input of the amplifier
(11 ) . whose output is connected in parallel to the input of
the low-pass filter (12J whose output is connected in
parallel to the inputs of the low-pass filter (J_4 and the
high-pass filter { ___) , whose outputs are connected with the
inputs of the analog-to-digital converter (9), whose output
is connected with the input of the computer (10), where the
signal from the photodiode (4) is divided by the signal from the photodiode ( _) and undergoes further digital processing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PL30741995A PL307419A1 (en) | 1995-02-21 | 1995-02-21 | System for monitoring the cerebrospinal fluid filled space of cerebrum |
| PLP.307419 | 1995-02-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1996025876A1 true WO1996025876A1 (en) | 1996-08-29 |
Family
ID=20064465
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/PL1995/000018 WO1996025876A1 (en) | 1995-02-21 | 1995-08-24 | Subarachnoidal space monitoring system |
Country Status (2)
| Country | Link |
|---|---|
| PL (1) | PL307419A1 (en) |
| WO (1) | WO1996025876A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2323440A (en) * | 1997-03-17 | 1998-09-23 | Johnson & Johnson Medical | Measuring thickness of a layer within a body |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4223680A (en) * | 1977-06-28 | 1980-09-23 | Duke University, Inc. | Method and apparatus for monitoring metabolism in body organs in vivo |
| US4590948A (en) * | 1984-01-20 | 1986-05-27 | Perimed Kb | Method and apparatus for measuring the blood flow in the superficial blood vessels of tissue |
| GB2228314A (en) * | 1989-02-16 | 1990-08-22 | Hamamatsu Photonics Kk | Optical examination apparatus |
| WO1992001216A1 (en) * | 1990-07-06 | 1992-01-23 | Kapsch Aktiengesellschaft | Process and device for qualitatively and quantitatively determining tissue-specific parameters of biological tissues |
-
1995
- 1995-02-21 PL PL30741995A patent/PL307419A1/en unknown
- 1995-08-24 WO PCT/PL1995/000018 patent/WO1996025876A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4223680A (en) * | 1977-06-28 | 1980-09-23 | Duke University, Inc. | Method and apparatus for monitoring metabolism in body organs in vivo |
| US4321930A (en) * | 1977-06-28 | 1982-03-30 | Duke University, Inc. | Apparatus for monitoring metabolism in body organs |
| US4590948A (en) * | 1984-01-20 | 1986-05-27 | Perimed Kb | Method and apparatus for measuring the blood flow in the superficial blood vessels of tissue |
| GB2228314A (en) * | 1989-02-16 | 1990-08-22 | Hamamatsu Photonics Kk | Optical examination apparatus |
| WO1992001216A1 (en) * | 1990-07-06 | 1992-01-23 | Kapsch Aktiengesellschaft | Process and device for qualitatively and quantitatively determining tissue-specific parameters of biological tissues |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2323440A (en) * | 1997-03-17 | 1998-09-23 | Johnson & Johnson Medical | Measuring thickness of a layer within a body |
Also Published As
| Publication number | Publication date |
|---|---|
| PL307419A1 (en) | 1995-06-12 |
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