U.S. patent application number 10/531852 was filed with the patent office on 2006-06-08 for arrangement and method for detecting abnormalities and inconsistencies in a body.
Invention is credited to John W. Belliveau, Giorgio Bonmassar.
Application Number | 20060122523 10/531852 |
Document ID | / |
Family ID | 32108052 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060122523 |
Kind Code |
A1 |
Bonmassar; Giorgio ; et
al. |
June 8, 2006 |
Arrangement and method for detecting abnormalities and
inconsistencies in a body
Abstract
A system for detecting abnormalities or inconsistencies and a
method to utilize the same are provided. In particular, a computer
system may be adapted to detect the abnormality or inconsistency
within at least a portion of a subject by generating internal
impedance data which indicates that an impedance change within the
portion of the subject has occurred. For example, the impedance
change may be associated with a change in at least one
characteristic of a blood vessel within the subject (such as a
change in a fluid flow rate within at least a portion of the
subject), a change in a fluid volume within at least a portion of
the subject, etc. The impedance change also may be associated with
the presence of a foreign object within the portion of the subject.
In an exemplary embodiment, it is possible to detect the
abnormality or inconsistency within the subject by generating a
continuous, real time internal impedance map indicating the
impedance change within the subject. Alternatively, the abnormality
or inconsistency may be detected within the subject by generating a
plurality of static internal impedance maps which indicate that the
impedance change within the subject has occurred.
Inventors: |
Bonmassar; Giorgio;
(Lexington, MA) ; Belliveau; John W.; (Boston,
MA) |
Correspondence
Address: |
DORSEY & WHITNEY LLP;INTELLECTUAL PROPERTY DEPARTMENT
250 PARK AVENUE
NEW YORK
NY
10177
US
|
Family ID: |
32108052 |
Appl. No.: |
10/531852 |
Filed: |
October 17, 2003 |
PCT Filed: |
October 17, 2003 |
PCT NO: |
PCT/US03/33009 |
371 Date: |
September 26, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60419256 |
Oct 17, 2002 |
|
|
|
Current U.S.
Class: |
600/506 |
Current CPC
Class: |
A61B 5/0536 20130101;
A61B 5/053 20130101; A61B 5/02007 20130101; A61B 5/369 20210101;
A61B 5/055 20130101 |
Class at
Publication: |
600/506 |
International
Class: |
A61B 5/02 20060101
A61B005/02 |
Claims
1. An arrangement, comprising: a computer system adapted to detect
an abnormality or an inconsistency within a subject by generating
internal impedance data, the internal impedance data indicating an
impedance change within at least one portion of the subject,
wherein the impedance change is associated with at least one of: a
change in at least one characteristic of a blood vessel within the
subject, and a presence of a foreign object within the at least one
portion of the subject.
2. The arrangement of claim 1, faker comprising: an electrical
stimulator adapted to apply a current to at least one pair of
electrodes that are positioned in a proximity of the at least one
portion of the subject; and an analog to digital (A/D) converter
adapted to measure voltage distributions resulting from the applied
current, wherein the internal impedance data is generated based on
the voltage distributions.
3. The arrangement of claim 1, wherein the impedance change
associated with the change in the at least one characteristic of
the blood vessel is at least one of: a change in a fluid flow rate
within the at least one portion of the subject, and a change in a
fluid volume within the at least one portion of the subject.
4. The arrangement of claim 3, wherein the fluid includes
blood.
5. The arrangement of claim 3, wherein the at least one portion of
the foreign object comprises a metal material.
6. The arrangement of claim 1, wherein the computer system
generates a continuous, real time internal impedance map to detect
the abnormality or inconsistency within the subject by generating,
and wherein the impedance map indicates the impedance change within
the subject.
7. The arrangement of claim 1, wherein the computer system
generates a plurality of static internal impedance maps to detect
the abnormality or inconsistency within the subject, and wherein
the impedance maps indicate the impedance change within the
subject.
8. The arrangement of claim 1, wherein the subject is a human
being, and wherein the computer system is further adapted to detect
the abnormality or the inconsistency within the human being by
generating the internal impedance data over a predetermined range
of frequencies.
9. The arrangement of claim 1, wherein the at least one portion of
the subject is a portion of a brain of the subject.
10. The arrangement of claim 1, wherein the at least one portion of
the subject is a portion of a torso of the subject.
11. The arrangement of claim 2, wherein the electrical stimulator
is a function generator.
12. The arrangement of claim 2, wherein the A/D converter is a
thirty-two channel, twenty-four bit A/D converter.
13. The arrangement of claim 12, wherein the computer system is
adapted to obtain spectral electrical impedance tomography
recordings and electroencephalography recordings,
simultaneously.
14. An arrangement, comprising: an electrical stimulator adapted to
apply a current to at least one pair of electrodes, the electrodes
being positioned on at least one portion of a subject; an analog to
digital (A/D) converter adapted to measure voltage distributions
resulting from the applied current; and a computer system adapted
to detect an abnormality or an inconsistency within the at least
one portion of the subject by generating internal impedance data,
the internal impedance data indicating the impedance change within
the subject wherein the impedance change is associated with at
least one of: a change in at least one characteristic of a blood
vessel within the subject, and a presence of a foreign object
within the at least one portion of the subject.
15. The arrangement of claim 14, wherein the impedance change
associated with the change in the at least one characteristic of
the blood vessel is at least one of: a change in a fluid flow rate
within the at least one portion of the subject, and a change in a
fluid volume within the at least one portion of the subject.
16. The arrangement of claim 15, wherein the fluid includes
blood.
17. The arrangement of claim 15, wherein the at least one portion
of the foreign object comprises a metal material.
18. The arrangement of claim 14, wherein the computer system
generates a continuous, real time internal impedance map to detect
the abnormality or inconsistency within the subject by generating,
and wherein the impedance map indicates the impedance change within
the subject.
19. The arrangement of claim 14, wherein the computer system
generates a plurality of static internal impedance maps to detect
the abnormality or inconsistency within the subject, and wherein
the impedance maps indicate the impedance change within the
subject.
20. The arrangement of claim 14, wherein the subject is a human
being, and wherein the computer system is further adapted to detect
the abnormality or the inconsistency within the human being by
generating the internal impedance data over a predetermined range
of frequencies.
21. The arrangement of claim 14, wherein the at least one portion
of the subject is a portion of a brain of the subject.
22. The arrangement of claim 14, wherein the at least one portion
of the subject is a portion of a torso of the subject.
23. The arrangement of claim 14, wherein the electrical stimulator
is a function generator.
24. The arrangement of claim 14, wherein the A/D converter is a
thirty-two channel, twenty-four bit A/D converter.
25. The arrangement of claim 24, wherein the computer system is
adapted to obtain spectral electrical impedance tomography
recordings and electroencephalography recordings,
simultaneously.
26. An arrangement, comprising: an electrical stimulator; a switch
coupled to the electrical stimulator; a plurality of electrodes
positioned on at least one portion of a subject, wherein each of
the electrodes is coupled to the switch; an analog to digital (A/D)
converter coupled to the switch and to each of the electrodes; and
a computer system adapted to detect an abnormality or inconsistency
within the subject by generating internal impedance data, the
internal impedance data indicating an impedance change within the
at least one portion of the subject, wherein the impedance change
is associated with at least one of: a change in at least one
characteristic of a blood vessel within the subject, and a presence
of a foreign object within the at least one portion of the
subject.
27. The arrangement of claim 26, wherein the impedance change
associated with the change in the at least one characteristic of
the blood vessel is at least one of: a change in a fluid flow rate
within the at least one portion of the subject, and a change in a
fluid volume within the at least one portion of the subject.
28. The arrangement of claim 27, wherein the fluid includes
blood.
29. The arrangement of claim 27, wherein at least a portion of the
foreign object comprises a metal material.
30. The arrangement of claim 26, wherein the computer system
generates a continuous, real time internal impedance map to detect
the abnormality or inconsistency within the subject by generating,
and wherein the impedance map indicates the impedance change within
the subject.
31. The arrangement of claim 26, wherein the computer system
generates a plurality of static internal impedance maps to detect
the abnormality or inconsistency within the subject and wherein the
impedance maps indicate the impedance change within the
subject.
32. The arrangement of claim 26, wherein the subject is a human
being, and wherein the computer system is further adapted to detect
the abnormality or the inconsistency within the human being by
generating the internal impedance data over a predetermined range
of frequencies.
33. The arrangement of claim 26, wherein the at least one portion
of the subject is a portion of a brain of the subject.
34. The arrangement of claim 26, wherein the at least one portion
of the subject is a portion of a torso of the subject.
35. The arrangement of claim 26, wherein the electrical stimulator
is a function generator.
36. The arrangement of claim 26, wherein the switch is a thirty-two
channel matrix switch.
37. The arrangement of claim 26, wherein the A/D converter is a
thirty-two channel, twenty-four bit A/D converter.
38. The arrangement of claim 37, wherein the computer system is
adapted to obtain spectral electrical impedance tomography
recordings and electroencephalography recordings,
simultaneously.
39. The arrangement of claim 26, wherein the computer system
further is coupled to the electrical stimulator.
40. An arrangement for use within a magnetic resonance imaging
environment, comprising: an electrical stimulator; a switch coupled
to the electrical stimulator via a filter; a plurality of
electrodes positioned on at least one portion of a subject, wherein
each of the electrodes is coupled to the switch; an analog to
digital (A/D) converter coupled to the switch and to each of the
electrodes; and a computer system coupled to the switch and to the
A/D converter, wherein the electrical stimulator applies a current
to at least one pair of the electrodes, and the A/D converter
measures voltage distribution and a current distribution resulting
from the applied current, wherein the computer system is adapted to
detect an abnormality or inconsistency within the subject by
generating internal impedance data, the internal impedance data
indicating an impedance change within the at least one portion of
the subject, and wherein the impedance change is associated with at
least one of: a change in at least one characteristic of a blood
vessel within the subject, and a presence of a foreign object
within the at least one portion of the subject.
41. The arrangement of claim 40, wherein the impedance change
associated with the change in the at least one characteristic of
the blood vessel is at least one of: a change in a fluid flow rate
within the at least one portion of the subject, and a change in a
fluid volume within the at least one portion of the subject.
42. The arrangement of claim 41, wherein the fluid includes
blood.
43. The arrangement of claim 41, wherein the at least one portion
of the foreign object comprises a metal material.
44. The arrangement of claim 40, wherein the computer system
generates a continuous, real time internal impedance map to detect
the abnormality or inconsistency within the subject by generating,
and wherein the impedance map indicates the impedance change within
the subject.
45. The arrangement of claim 40, wherein the computer system
generates a plurality of static internal impedance maps to detect
the abnormality or inconsistency within the subject, and wherein
the impedance maps indicate the impedance change within the
subject.
46. The arrangement of claim 40, wherein the subject is a human
being, and wherein the computer system is further adapted to detect
the abnormality or the inconsistency within the human being by
generating the internal impedance data over a predetermined range
of frequencies.
47. The arrangement of claim 40, wherein the at least one portion
of the subject is a portion of a brain of the subject.
48. The arrangement of claim 40, wherein the at least one portion
of the subject is a portion of a torso of the subject.
49. The arrangement of claim 40, wherein the electrical stimulator
is a function generator.
50. The arrangement of claim 40, wherein the switch is a thirty-two
channel matrix switch.
51. The arrangement of claim 40, wherein the A/D converter is a
thirty-two channel, twenty-four bit A/D converter.
52. The arrangement of claim 51, wherein the computer system is
adapted to obtain spectral electrical impedance tomography
recordings and electroencephalography recordings,
simultaneously.
53. The arrangement of claim 40, wherein the computer system is
coupled to the electrical stimulator.
54. The arrangement of claim 40, wherein the computer system and
the electrical stimulator are positioned externally form a magnetic
resonance imaging room, and wherein the switch, the A/D converter
and the electrodes are positioned inside of the magnetic resonance
imaging room.
55. An arrangement, comprising: means for applying a current to at
least one pair of electrodes that are positioned on at least one
portion of a subject; means for measuring voltage distributions
resulting from the applied current; and a computer system adapted
to detect an abnormality or inconsistency within the subject by
generating internal impedance data, the internal impedance data
indicating an impedance change within the at least one portion of
the subject, wherein the impedance change is associated with at
least one of: a change in at least one characteristic of a blood
vessel within the subject, and a presence of a foreign object
within the at least one portion of the subject.
56. The arrangement of claim 55, wherein the impedance change
associated with the change in the at least one characteristic of
the blood vessel is at least one of: a change in a fluid flow rate
within the at least one portion of the subject, and a change in a
fluid volume within the at least one portion of the subject.
57. The arrangement of claim 56, wherein the fluid includes
blood.
58. The arrangement of claim 56, wherein the at least one portion
of the foreign object comprises a metal material.
59. The arrangement of claim 55, wherein the computer system
generates a continuous, real time internal imp ce map to detect the
abnormality or inconsistency within the subject by generating, and
wherein the impedance map indicates the impedance change within the
subject.
60. The arrangement of claim 55, wherein the computer system
generates a plurality of static internal impedance maps to detect
the abnormality or inconsistency within the subject, and wherein
the impedance maps indicate the impedance change within the
subject.
61. The arrangement of claim 55, wherein the subject is a human
being, and wherein the computer system is further adapted to detect
the abnormality or the inconsistency within the human being by
generating the internal impedance data offer a predetermined range
of frequencies.
62. The arrangement of claim 55, wherein the at least one portion
of the subject is a portion of a brain of the subject.
63. The arrangement of claim 55, wherein the at least one portion
of the subject is a portion of a torso of the subject.
64. The arrangement of claim 55, wherein the means for applying the
current comprises an electrical stimulator.
65. The arrangement of claim 64, wherein the electrical stimulator
is a function generator.
66. The arrangement of claim 55, wherein the means for measuring
the voltage distributions comprises an A/D converter.
67. The arrangement of claim 66, wherein the A/D converter is a
thirty-two channel, twenty-four bit A/D converter.
68. The arrangement of claim 55, wherein the computer system is
adapted to obtain spectral electrical impedance tomography
recordings and electroencephalography recordings,
simultaneously.
69. An abnormality or inconsistency detection arrangement,
comprising: an analog to digital converter adapted to obtain
spectral electrical impedance tomography recordings and current
density recordings from a subject, simultaneously.
70. The arrangement of claim 69, further comprising: a computer
system adapted to detect at least one of the abnormality and the
inconsistency within the subject by generating internal impedance
data based on the spectral electrical impedance tomography
recordings and the current density recordings, the internal
impedance data indicating an impedance change within at least one
portion of the subject; and an electrical stimulator adapted to
apply a current to at least one pair of electrodes positioned on
the at least one portion of the subject.
71. A method of detecting an abnormality or an inconsistency,
comprising the steps of: generating internal impedance data
indicating an impedance change within a subject, wherein the
impedance change is associated with at least one of a change in at
least one characteristic of a blood vessel within the subject and a
presence of a foreign object within at least one portion of the
subject; and detecting the abnormality or inconsistency based on
the internal impedance data.
72. The method of claim 71, further comprising the steps of:
applying a current to at least one pair of the electrodes which are
positioned on the at least one portion of the subject; and
measuring voltage distributions resulting from the applied
current.
73. The method of claim 71, wherein the impedance change associated
with the change in the at least one characteristic of the blood
vessel is at least one of: a change in a fluid flow rate within the
at least one portion of the subject, and a change in a fluid volume
within the at least one portion of the subject.
74. The method of claim 73, wherein the fluid includes blood, and
wherein the at least one portion of the foreign object comprises a
metal material.
75. The method of claim 71, wherein the step of generating the
internal impedance data comprises the step of generating a
continuous, real time internal impedance map indicating an
impedance change within the subject.
76. The method of claim 71, wherein the step of generating the
internal impedance data comprises the step of generating a
plurality of static internal impedance maps that indicate the
impedance change within the subject.
77. The method of claim 71, wherein the subject is a human being,
and wherein the computer system is further adapted to detect the
abnormality or the inconsistency within the human being by
generating the internal impedance data over a predetermined range
of frequencies.
78. The method of claim 71, wherein the at least one portion of the
subject is one of a portion of a brain of the subject and a portion
of a torso of the subject.
79. The method of claim 71, further comprising the step of
simultaneously obtaining spectral electrical impedance tomography
recordings and electroencephalography recordings from the
subject.
80. A method of detecting an abnormality or an inconsistency,
comprising the steps of: positioning a plurality of electrodes on
at least one portion of a subject; applying a current to at least
one pair of the electrodes; measuring voltage distributions
resulting from the applied current; and detecting the abnormality
or inconsistency within the subject by generating internal
impedance data which indicates an impedance change within the at
least one portion of the subject, wherein the impedance change is
associated with at least one of: a change in at least one
characteristic of a blood vessel within the subject, and a presence
of a foreign object within the at least one portion of the
subject.
81. The method of claim 80, wherein the impedance change associated
with the change in the at least one characteristic of the blood
vessel is at least one of: a change in a fluid flow rate within the
at least one portion of the subject, and a change in a fluid volume
within the at least one portion of the subject.
82. The method of claim 80, wherein the internal impedance data is
generated using a continuous, real time internal impedance map that
indicates that an impedance change within the subject has
occurred.
83. The method of claim 80, wherein the internal impedance data is
generated using a plurality of static internal impedance maps that
indicate the impedance change within the subject.
84. The method of claim 80, wherein the subject is a human being,
and wherein the computer system is further adapted to detect the
abnormality or the inconsistency within the human being by
generating the internal impedance data over a predetermined range
of frequencies.
85. The method of claim 80, further comprising the step of
simultaneously obtaining spectral electrical impedance tomography
recordings and electroencephalography recordings from the
subject.
86. A method of detecting an abnormality or inconsistency within a
magnetic resonance imaging environment, comprising the steps of:
positioning a plurality of electrodes on at least one portion of a
subject; applying a current to at least one pair of the electrodes;
filtering the current before the current is transmitted inside the
magnetic resonance imaging environment; measuring voltage
distributions resulting from the applied current; and detecting an
abnormality within the subject by generating internal impedance
data that indicates an impedance change within the at least one
portion of the subject, wherein the impedance change is associated
with at least one of: a change in at least one characteristic of a
blood vessel within the subject, and a presence of a foreign object
within the at least one portion of the subject.
87. The method of claim 86, wherein the impedance change associated
with the change in the at least one characteristic of the blood
vessel is at least one of: a change in a fluid flow rate within the
at least one portion of the subject, and a change in a fluid volume
within the at least one portion of the subject.
88. The method of claim 86, wherein the internal impedance data is
generated using a continuous, real time internal impedance map that
indicates the impedance change within the subject.
89. The method of claim 86, wherein the internal impedance data is
generated using a plurality of static internal impedance maps that
indicate the impedance change within the subject.
90. The method of claim 86, wherein the subject is a human being,
and wherein the computer system is further adapted to detect the
abnormality or the inconsistency within the human being by
generating the internal impedance data over a predetermined range
of frequencies.
91. A method of detecting an abnormality or inconsistency,
comprising the step of: simultaneously obtaining spectral
electrical impedance tomography recordings and
electroencephalography recordings from a subject; and detecting the
abnormality or inconsistency using the simultaneously obtained
spectral electrical impedance tomography recordings and
electroencephalography recordings.
92. An arrangement, comprising: a computer system adapted to detect
an abnormality or an inconsistency within a subject by generating
internal impedance data over a predetermined range of frequencies,
the internal impedance data indicating an impedance change within
at least one portion of the subject.
93. The arrangement of claim 92, wherein the computer system is
further adapted to generate data associated with a flow of current
through the at least one portion of the subject and to modify the
data associated with the flow of current through the at least one
portion of the subject based on at least one predetermined
characteristic of the subject.
94. The arrangement of claim 93, wherein the at least one
predetermined characteristic is at least one of an age of the
subject, a sex of the subject, and a height of the subject.
95. The arrangement of claim 93, wherein the impedance change is
associated with at least one of a change in at least one
characteristic of a blood vessel within the subject and a presence
of a foreign object within the at least one portion of the
subject.
96. A method of detecting an abnormality or an inconsistency,
comprising the step of generating internal impedance data over a
predetermined range of frequencies, the internal impedance data
indicating an impedance change within at least one portion of the
subject.
97. The method of claim 96, wherein the step of generating the
internal impedance data comprises the substeps of: generating data
associated with a flow of current through the at least one portion
of the subject; and modifying the data associated with the flow of
current through the at least one portion of the subject based on at
least one predetermined characteristic of the subject.
98. The arrangement of claim 97, wherein the at least one
predetermined characteristic is at least one of an age of the
subject, a sex of the subject, and a height of the subject.
99. The arrangement of claim 97, wherein the impedance change is
associated with at least one of a change in at least one
characteristic of a blood vessel within the subject and a presence
of a foreign object within the at least one portion of the subject.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from U.S.
Provisional Patent Application No. 60/419,256, which is entitled
"Arrangement and Method for Detecting Abnormalities and
Inconsistencies in a Body," and was filed on Oct. 17, 2002, the
disclosure of which is incorporated herein by reference in its
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to an arrangement
and method for detecting abnormalities and inconsistencies within a
subject. In particular, the present invention is directed to an
arrangement and method in which a computer system detects an
abnormality or inconsistency within the subject by generating
internal impedance data over a predetermined range of frequencies
to indicate an impedance change within the subject
BACKGROUND OF THE INVENTION
[0003] Conventional electroencephalography (EEG) systems have been
employed to record brain waves in a patient by measuring intrinsic
voltages or currents produced by the brain of the patient.
Specifically, conventional EEG systems detect and amplify brain
waves, and convert the brain waves into digital data to be compared
with data associated with normal brain waves. These systems may be
employed to detect possible spinal cord injuries, stroke, epilepsy
and a variety of brain dysfunctions related to a psychology of a
patient ranging from substance abuse to psychosis. For example,
certain conventional EEG systems include a plurality of electrodes
which can be positioned on the scalp of a patient. The electrodes
are coupled to a switching system, which in turn is coupled to a
preamplifier that is connected to an amplifier. The amplifier is
connected to a sixteen (16) bit analog to digital (A/D) converter,
and the A/D converter is connected to a display. The A/D converter
samples the EEG waves, and converts the EEG waves into the digital
data to be shown on the display. However, such conventional system
only may be adapted to obtain EEG recordings.
[0004] Conventional electrical impedance tomography (EIT) systems
have been employed to produce electrical impedance images in
medical applications. These EIT systems measure current or voltage
distributions resulting from the currents being applied to a
portion of the body of the patient, and generate an image of such
portion of the body based on the measured current or voltage
distributions. These conventional systems have been employed, e.g.
to display changes in the thorax during breathing, the stomach
during a gastric emptying, the heart during intraventricular
hemorrhage, and the brain due to a physiological cerebral activity,
and to monitor the progression of various lung diseases. For
example, the conventional EIT system can be adapted to image
changes in the brain due to a physiological cerebral activity may
include a current generator coupled to a switching arrangement,
such as a computer controlled multiplexor. A plurality of
electrodes are positioned in contact with the patient's scalp, and
are coupled to the switching arrangement. An amplifier is coupled
to the electrodes, a sixteen (16) bit A/D converter is connected to
the amplifier, and a computer is connected to the A/D
converter.
[0005] In operation, the current generator applies current to the
electrodes. For example, the current may be applied sequentially to
the electrode pairs, or simultaneously to multiple pairs of
electrodes, which is known as a parallel data collection. Moreover,
potential differences between the electrode pairs may be measured
to obtain analog signals, and these analog signals may be amplified
by the amplifier. Subsequently, the A/D converter converts the
analog signals to digital signals, and forwards the digital signals
to the computer. In this manner, the data may be processed by the
reconstruction software to obtain image changes in the brain due to
a physiological cerebral activity, and provide these images on a
display. However, such conventional system may be adapted to only
obtain EIT recordings that are e.g., associated with the
physiological cerebral activity, and may also be adapted to only
monitor only certain organs. Moreover, such convention system only
may obtain EIT recordings at a particular frequency.
SUMMARY OF THE INVENTION
[0006] Therefore, a need has arisen to provide an arrangement and
method for detecting abnormalities and inconsistencies which
overcome the above-described and other shortcomings of the related
art.
[0007] One of the advantages of the present invention is that the
arrangement and method are provided which may detect the
abnormality or inconsistency within a subject by generating
internal impedance data that indicates the occurrence and/or
particulars of an impedance change within the associate subject has
for at least one characteristic of a blood vessel within the
subject. For example, the impedance change associated with the
change in the characteristic of the blood vessel may be a change of
a fluid flow rate within at least a portion of the subject, a
change of a fluid volume within at least a portion of the subject,
etc. Another advantage of the system and method of the present
invention is that the abnormality or inconsistency within a subject
may be detected by generating internal impedance data that
indicates an impedance change within the subject associated that is
with the presence of a foreign object within at least a portion of
the subject. Yet another advantage of the system and method of the
present invention is that they allow simultaneous spectral
electrical impedance tomography (SEIT) recordings and
electroencephalography recordings, and/or simultaneous spectral
electrical impedance tomography recordings and current density
recordings to be obtained from the subject. Still another advantage
of the present invention is that the system may be a portable
system, so that it may be used by first responders to accidents,
e.g., Emergency Medical Service (EMS) personnel, in order to assist
the responders in obtaining data which is useful in making
decisions concerning abnormalities or inconsistencies, such as
injuries to the brain or torso involving foreign objects and/or
internal bleeding.
[0008] According to an exemplary embodiment of the present
invention, an arrangement and method utilize a computer system
which may be adapted to detect abnormalities and inconsistencies
within a subject, e.g., a human or an animal, by generating
internal impedance data which indicates the occurrence and/or the
particulars of an impedance change within at least a portion (e.g.
a brain or a torso) of the subject has occurred. For example, the
impedance change may be associated with a change in at least one
characteristic of a blood vessel within the subject, such as a
change in a fluid (e.g., blood, flow rate within at least a portion
of the subject) a change in a fluid volume within at least a
portion of the subject, etc. The impedance change may also be
associated with the presence of a foreign object (e.g., a metal
foreign object) within at least a portion of the subject. Moreover,
the internal impedance data may be obtained over a predetermined
range of frequencies, such as between about 0.01 Hz and about 100
KHz. As examples the Cole-Cole or 4-Cole-Cole models may be used to
determine tissue's impedence at a given frequency. In another
exemplary embodiment of the present invention, the computer system
may adapted to detect the abnormality or inconsistency within the
subject by generating a continuous, real time internal impedance
map which indicates the occurrence and/or the particulars of the
impedance change within the portion of the subject. Alternatively,
the computer system may be adapted to detect the abnormality or
inconsistency within the subject by generating a plurality of
static internal impedance maps which also may indicate the
occurrence and/or the particulars of the impedance change within
the subject.
[0009] In yet another exemplary embodiment of the present
invention, it is possible to utilize an electrical stimulator, a
switch coupled to the electrical stimulator, and a plurality of
electrodes positioned on at least a portion of the subject and
coupled to the switch. An analog to digital (A/D) converter can
also be provided such that it is coupled to the switch and to each
of the electrodes. Moreover, the computer system may be coupled to
the switch and to the A/D converter. In operation, the electrical
stimulator may apply current to at least a pair of the electrodes,
and the A/D converter may measure voltage or current distributions
resulting from the applied current. The applied current may be
white noise or pink noise, depending on whether SEIT are being
recorded, or whether SEIT and EEG signals are being simultaneously
recorded. The A/D) converter may also transmit the voltage or
current distributions to the computer system so that the computer
system may generate the internal impedance data based on the
voltage or current distributions.
[0010] As examples, the computer system may use the Barber-Brown
linear backprojection method, the Calderon approach, the moment
method, the one-step Newton method, the least squares method, or
constrain minimixation methods in combination with an approximation
model of the at least one portion of the subject (e.g. the head of
the subject) to generate the internal impedance maps. Specifically,
a map of the current flow through the head may be generated using
the Barber-Brown backprojection method. Moreover, the computer
system may include a database of approximated head models, and each
approximation head model may be based on predetermined
characteristics associated with an imaginary subject, such as a
predetermined height, age, sex, etc., of the imaginary subject.
Each approximation head model may indicate an expected current flow
through the head of a subject who's characteristics are the same as
or are similar to the predetermined characteristics. The computer
system may select an appropriate approximated head model for the
subject based on the characteristics of the subject, and the
computer system then may alter the current flow map obtained using
the Barber-Brown linear backprojection method based on the selected
approximation head model to obtain the internal impedance maps.
[0011] According to still yet another exemplary embodiment of the
present invention the A/D converter is, e.g., a twenty-four (24)
bit, thirty-two (32) channel A/D converter, adapted to obtain
simultaneous spectral electrical impedance tomography recordings
and electroencephalography recordings from the subject. In a
variation of this embodiment, the electrical stimulator and the
computer system can be positioned externally from a magnetic
resolution environment, such that the twenty-four (24) bit,
thirty-two (32) channel A/D converter may be adapted to obtain
simultaneous spectral electrical impedance tomography recordings
and current density recordings from the subject.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] For a more complete understanding of the present invention,
the needs satisfied thereby, and the objects, features, and
advantages thereof, reference now is made to the following
descriptions taken in connection with the accompanying
drawings.
[0013] FIG. 1 is a schematic diagram of a first exemplary
embodiment of an arrangement according to a first embodiment of the
present invention for detecting abnormalities and inconsistencies
in a subject.
[0014] FIG. 2 is a schematic diagram of a second exemplary
embodiment of the arrangement of the present invention.
[0015] FIG. 3a is a flow diagram of a first exemplary embodiment of
a method according to the present invention for detecting
abnormalities and inconsistencies within the subject.
[0016] FIG. 3b is a flow diagram depicting a variation of the
method of FIG. 3a.
[0017] FIG. 4a is a flow diagram of a second exemplary embodiment
of the method according to the present invention.
[0018] FIG. 4b is a flow diagram depicting a first variation of the
method of FIG. 4a.
[0019] FIG. 4c is a flow diagram depicting a second variation of
the method of FIG. 4a.
DETAILED DESCRIPTION
[0020] Exemplary embodiments of the present invention and their
advantages may be understood by referring to FIGS. 1-4b, like
numerals being used for like commending parts in the various
drawings.
[0021] Referring to FIG. 1, a first exemplary embodiment of an
arrangement 100 according to the present invention for detecting
abnormalities and inconsistencies in a subject is provided. The
arrangement 100 may include a computer system 110 which can be
adapted to detect an abnormality or inconsistency within at least a
portion of a subject 116. Specifically, the computer system 110 may
detect the abnormality or biological inconsistency by generating
internal impedance data. For example, the computer system 110 may
generate the internal impedance data over a predetermined range of
frequencies, such as between about 0.01 Hz and about 100 KHz. This
internal data indicates the occurrence and/or the particulars of an
impedance change within the subject 116 (associated with a change
in at least one characteristic of a blood vessel within the
subject). Alternatively, the internal impedance data may be
associated with a presence of a foreign object within at least a
portion of the subject 116. In an exemplary embodiment of the
present invention, the impedance change associated with the change
in the at least one characteristic of the blood vessel may be a
variance in a fluid flow rate (e.g., a blood flow rate) within at
least a portion of the subject 116. Alternatively, the impedance
change can be a change in a fluid volume (e.g., a blood volume)
within at least a portion of the subject.
[0022] In another exemplary embodiment of the present invention,
the subject 116 may be a human being an animal, etc., and the
arrangement 100 may be adapted to detect the abnormality within a
brain, a torso, etc. of the subject 116. Moreover, the
abnormalities or biological inconsistencies may include an injury
(such an injury associated with internal bleeding), the presence of
a foreign object within the subject 116, or any other internal or
external abnormality or biological inconsistency resulting in a
change in impedance within the subject 116. In these exemplary
embodiments of the present invention, the impedance of blood is
generally smaller than the impedance of a brain tissue (i.e. the
conductivity of the blood is greater than the conductivity of the
brain tissue), and is also less than the impedance of a tissue in
the torso and other parts of the subject 116. When the blood volume
or the blood flow in the brain, the torso, or any other part of the
subject 116 increases (such as when a blood vessel is believed to
be likely punctured or expanded), the impedance of at least a
portion of the subject 116 decreases. For example, when the blood
vessel is punctured, the blood flows from the punctured blood
vessel, and the impedance of the tissue adjacent to the punctured
blood vessel may decrease. Similarly, when the blood volume or the
blood flow in the brain, the torso, or any other part of the
subject 116 decreases (such as when a blood vessel is constricted),
the impedance of at least a portion of the subject 116 may
increase. Moreover, the impedance of a foreign object (e.g. a metal
foreign object, such as a bullet, shrapnel, etc.) may be smaller
than the impedance of the brain tissue, and can also be smaller
than the impedance of the tissue in the torso or other parts of the
subject 116. As such, when a foreign object is present in the
brain, torso, or any other part of the subject 116, the impedance
of at least a portion of the subject 116 is decreased. As such, the
arrangement 100 may be employed to determine whether the
abnormality or biological inconsistency may exist (e.g., an injury
to or the presence of a foreign object within the subject 116) by
generating data associated with these changes in the impedance.
[0023] In particular, an exemplary embodiment of the arrangement
100 of the present invention may also include a plurality of
electrodes 106 positioned on at least a portion of the subject 116,
an electrical stimulator 102 (e.g., a function generator, such as a
current function generator or a voltage function generator), a
matrix switch 104 (e.g., a thirty-two (32) channel, analog matrix
switch), and an A/D converter 108 (e.g., a thirty-two (32) channel,
twenty-four (24) bit A/D converter). The electrical stimulator 102
may be coupled to the matrix switch 104, and the matrix switch 104
may be coupled to the electrodes 106 and the computer 110.
Moreover, the electrodes 106 may be coupled to the A/D converter
108, which can be coupled to the computer system 110, and the
computer system 110 may be coupled to the electrical stimulator
102. For example, the matrix switch 104 may be connected to the
computer system 110 using an optical digital link, and the A/D
converter 108 can be connected to the computer system 110 using an
optical USB link. In this configuration, the computer system 110
may be used to control each component of the arrangement 100.
[0024] In operation, the electrical stimulator 102 can apply a
current or a voltage to at least one pair (e.g., may simultaneously
apply a current or a voltage to eight (8) pairs) of the electrodes
106, and the A/D converter 108 can continuously measure the voltage
and/or current distributions at the electrodes 106 to which the
current is not being applied. The applied current may be white
noise or pink noise. For example, when the A/D converter 108 is
obtaining SEIT recordings from the subject 112, the applied current
may be white noise. Specifically, the frequency range of white
noise may not overlap with the frequency range at which SEIT
signals are detected (e.g., between about 50 Hz and about 100 KHz).
Consequently, the white noise may not interfere with the
recordation of SEIT signals. However, when the A/D converter 108 is
simultaneously obtaining EEG recordings and SEIT recordings from
the subject 112, the applied current may be pink noise.
Specifically, the frequency range of pink noise may not overlap
with the frequency range at which EEG signals are detected (e.g.,
between about 0.01 Hz and about 50 Hz). Consequently, the pink
noise may not may not interfere with the recordation of EEG
signals. If the pink noise does interfere with the recordation of
EEG signals, the unwanted pink noise readily may be filtered out
(e.g., using an adaptive filter). Moreover, although the frequency
range of pink noise may overlap with the frequency range at which
SEIT signals are detected, the effect of such pink noise on the
SEIT signals may be minimal.
[0025] In any of the above-described exemplary embodiments of the
present invention, after electrical stimulator 102 applies the
current or the voltage to the at least one pair of the electrodes
106, and the A/D converter 108 measures the voltage and/or current
distributions at the electrodes 106 to which the current or voltage
is not being applied, the matrix switch 104 switches the current to
another one or more parts of the electrodes 106, and the A/D
converter 108 obtains additional voltage or current distribution
measurements from those electrodes. Thereafter, the A/D converter
108 converts the analog voltages into digital data, and forwards
the converted digital data to the computer system 110.
[0026] When the computer system 110 receives the digital data from
the A/D converter 108, the computer system 110 can generate the
internal impedance data which indicates the occurrence and/or the
particulars of the impedance change within the subject 116. The
impedance change is associated with a change in at least one
characteristic of a blood vessel within the subject and/or with a
presence of a foreign object within at least a portion of the
subject 116. For example, the computer system 110 may generate a
continuous, real time internal impedance map indicating the
impedance change within the subject 116. Alternatively, the
computer system 110 may generate a plurality of static internal
impedance maps indicating the impedance change within the subject
116. In addition, the computer system 110 may be adapted to
compensate for impedance variations resulting from the attachment
of the at least one electrode 106 to the subject 116 (e.g.,
variations resulting from the use of paste to attached the at least
one electrode to the subject 116, cleansing of the portion of the
subject 116 which the at least one electrode is attached, etc.).
For example, the computer system 110 may compensate for the
impedance variations resulting from the attachment of the at least
one electrode 106 to the subject 116 by using frequency spectrum
normalizations.
[0027] In an exemplary embodiment of the present invention, the
computer system 110 may generate the internal impedance maps by
using a known linear approximation method, such as the Barber-Brown
linear backprojection method, Calderon's method, a moment method,
or a one-step Newton method. Each of these linear approximation
methods readily will be understood by those of ordinary skill in
the art. In another exemplary embodiment of the present invention,
the computer system 110 may generate the internal impedance maps by
using a known iterative method, such as by employing a
layer-stripping algorithm.
[0028] Alternatively, the computer system 110 may use the
Barber-Brown linear backprojection method in combination with an
approximation model of the at least one portion of the subject 116
(e.g., the head of the subject 116) to generate the internal
impedance maps. For example, in accordance with the Barber-Brown
linear backprojection method, a pair of detectors (not shown) may
be positioned on opposite sides of the head and may obit the head.
As the detectors orbit the head, two twin particles may be
continuously transmitted to the detectors, and a map of the current
flow though the head may be generated. However, as the frequency of
the current flowing through the head decreases, the difficulty of
obtaining data sufficient to generate an accurate map of the
current flow through the head increases. Consequently, at least
certain frequencies, using the Barber-Brown linear backprojection
method by itself may not be sufficient to generate an accurate map
of the current flow through the head. In this exemplary embodiment
of the present invention, the approximation model of the head may
be used in combination with the above-described current data
obtained using the Barber-Brown linear backprojection method to
generate the internal impedance maps. Specifically, the computer
system 110 may include a database of approximated head models, and
each approximation head model may be based on predetermined
characteristics associated with an imaginary subject, such as a
predetermined height, age, sex, etc., of the imaginary subject.
Moreover, each approximation head model may indicate an expected
current flow through the head of a subject 116 who's
characteristics are the same as or are similar to the predetermined
characteristics. The computer system 110 may select an appropriate
approximated head model for the subject 116 based on the
characteristics of the subject 116, and the computer system 110
then may alter the current flow map obtained using the Barber-Brown
linear backprojection method based on the selected approximation
head model to obtain the internal impedance maps.
[0029] In another variation of the present invention, the
arrangement 100 may be a portable abnormality detection
arrangement. As such, the arrangement 100 may be used by first
responders to accidents (e.g., EMS personnel) in order to assist
the responder in obtaining data that is useful in making decisions
concerning abnormalities or biological inconsistencies, such as
injuries to the brain or torso involving foreign objects and/or
internal bleeding. Further, in yet another variation of the
arrangement 100, the A/D converter 108 can be a thirty-two (32)
channel, twenty-four (24) bit A/D converter, and thus the bandwidth
of the arrangement 100 may be sufficient to allow the computer
system 110 to obtain simultaneous SEIT and EEG recordings. These
simultaneous SEIT and EEG recordings allow the computer system 110
to gather information related to different types of medical
problems, simultaneously. For example, the SEIT recordings may be
used to detect the presence of the foreign object in the subject
116, and can detect an increase in the blood to the brain, torso,
or any other body part due to trauma. In contrast, the EEG
recordings may be used to detect strokes, epilepsy, spinal cord
injuries, substance abuse, and any other injury or occurrence which
can affect the brain to emit the corresponding waves.
[0030] FIG. 2 shows a second exemplary embodiment of the
arrangement 200 for detecting the abnormalities or biological
inconsistencies for use within a magnetic resonance imaging (MRI)
environment 114 according to the present invention. The features
and advantages of the second embodiment of the arrangement 200 of
the present invention are substantially similar to the features and
advantages of the second embodiment of the present invention,
except as provided herein below. In the second exemplary embodiment
of the arrangement 200 of the present invention, the electrical
stimulator 102 and the computer system 110 may be positioned
externally from the MRI environment 114, and the arrangement 200
may further include at least one filter 112 (e.g., at least one
radio frequency filter) communicatively connected between the
electrical stimulator 102 and the matrix switch 104. Moreover, the
filter 112 may be adapted to filter the current applied by the
electrical stimulator 102 before the current is transmitted into
the MRI environment 114.
[0031] In this exemplary embodiment of the present invention, the
A/D converter 108 may be adapted to obtain simultaneous SEIT
recordings and current density recordings from the subject 116.
Specifically, imaging techniques such as a current density imaging
("CDI") technique can be utilized to generate electrical current
density distributions in a volume of the subject 116 being examined
using the MRI techniques. For example, when the electrical
stimulator 102 applies the electrical current to the subject 116,
the computer system 110 may receive MRI data and SEIT data from the
A/D converter 108. Using known mathematical techniques, the
computer system 110 can process the MRI data so as to convert the
MRI data into current density distribution data, which may be used
to determine a current flow or a current path within the subject
116. After the current flow within the subject 116 is determined,
the location of particular portions of the subject 116 in which all
impedance change or impedance spike occurs may be determined more
precisely. Consequently, an internal impedance map, generated by
the computer system 110 based on the SEIT data and the current
density distribution data, may have a greater spatial resolution
than an internal impedance map which is generated based on the SEIT
data.
[0032] Referring to FIG. 3a, a flow diagram of a first exemplary
embodiment of a method 300 which can be used by the arrangement 100
of FIG. 1 is depicted. In step 310, a plurality of electrodes 106
may be positioned on at least a portion of the subject 116. In step
320, a current can be applied to at least one pair of the
electrodes 106 (or even to a single electrode). In step 330,
voltage or current distributions resulting from the applied current
may be measured. Then, in step 340, the internal impedance data is
generated. A user of the arrangement 100 determines whether the
internal impedance data indicates an impedance change within the
subject 116 in step 350. This impedance change is associated with a
change in the blood vessel characteristic and/or a presence of the
foreign object within at leas a portion of the subject 116.
Referring to FIG. 3b, in a variation of the first exemplary
embodiment of the method 300 according to the present invention,
step 350 may be replaced by step 350'. In step 350', the user of
the arrangement 100 determines whether the internal impedance data
indicates the impedance change within subject 116 that is
associated with a change in fluid flow rate (e.g., a blood flow
rate) and/or the change in fluid volume (e.g., a blood volume)
within the subject 116. In either one of the variants of the method
300 illustrated in FIGS. 3a and 3b, if the internal impedance data
indicates such impedance change, in step 360, the user of the
arrangement 100 detects an abnormality within the subject 116. If
the internal impedance data does not indicate such an impedance
change, in step 370, the user of the arrangement 100 detects the
absence of an abnormality or biological inconsistency within the
subject 116.
[0033] Referring to FIG. 4a, a flow diagram of a second embodiment
of a method 400 according to the present invention which is used by
the arrangement 200 of FIG. 2 is depicted. In step 410, the
electrodes 106 may be positioned on at least a portion of the
subject 116. In step 420, the current can be applied to at least a
pair of the electrodes 106. Further, in step 430, the current may
be filtered before the current is transmitted inside the MRI
environment. In step 440, the voltage or current distributions
resulting from the applied current may be measured. Referring to
FIG. 4b which shows a first variation of the second exemplary
embodiment of the method 400 according to the present invention,
this method is substantially the same as that of FIG. 4a, except
steps 440a and 440b can also be provided. In step 440a, MRI data
may be acquired, and in step 440b, the MRI data may be converted
into voltage or current distribution data. Moreover, in step 450,
the internal impedance data is generated. For example, the internal
impedance data can be based on the voltage or current
distributions. In step 460, the user of the arrangement 200
determines whether the internal impedance data indicates the dance
change within the subject 116 associated with a change in a blood
vessel characteristics and/or a presence of the foreign object
within at least a portion of the subject 116. Referring to FIG. 4c,
in a second variation of the second exemplary embodiment of the
method 300 of the present invention, step 460 may be replaced by
step 460'. In step 460', the user of the arrangement 200 deter
whether the internal impedance data indicates the impedance change
within subject 116 associated with the change in fluid flow rate
(e.g., the blood flow rate) and/or a change in fluid volume (e.g.,
the blood volume) within the subject 116. In either of the flow
diagrams of FIGS. 4a and 4b, if the internal impedance data
indicates such impedance change, in step 470, the user of the
arrangement 200 detects an abnormality within the subject 116. If
the internal impedance data does not indicate such impedance
change, in step 480, the user of the arrangement 200 detects the
absence of the abnormality or biological inconsistency within the
subject 116.
[0034] While the invention has been described in connection with
preferred embodiments, it will be understood by those of ordinary
skill in the art that other variations and modifications of the
preferred embodiments described above may be made without departing
from the scope of the invention. Other embodiments will be apparent
to those of ordinary skill in the art from a consideration of the
specification or practice of the invention disclosed herein. It is
intended that the specification and the described examples are
considered as exemplary only, with the true scope and spirit of the
invention indicated by the following claims.
* * * * *