The present invention relates to an improved breast electrode array and method for detecting and diagnosing disease states in a living organism by using a plurality of electrical impedance measurements.
Methods for screening and diagnosing diseased states within the body are based on sensing a physical characteristic or physiological attribute of body tissue, and then distinguishing normal from abnormal states from changes in the characteristic or attribute. For example, X-ray techniques measure tissue physical density, ultrasound measures acoustic density, and thermal sensing techniques measure differences in tissue heat. Another measurable property of tissue is its electrical impedance; i.e., the resistance tissue offers to the flow of electrical current through it. Values of electrical impedance of various body tissues are well known through studies on intact humans or from excised tissue made available following therapeutic surgical procedures. In addition, it is well documented that a decrease in electrical impedance occurs in tissue as it undergoes cancerous changes. This finding is consistent over many animal species and tissue types, including, for example human breast cancers.
One technique for screening and diagnosing diseased states within the body using electrical impedance is disclosed in U.S. Pat. No. 6,122,544. In this patent data are obtained in organized patterns from two anatomically homologous body regions, one of which may be affected by disease. One subset of the data so obtained is processed and analyzed by structuring the data values as elements of an impedance matrix. The matrices can be further characterized by their eigenvalues and eigenvectors. These matrices and/or their eigenvalues and eigenvectors can be subjected to a pattern recognition process to match for known normal or disease matrix or eigenvalue and eigenvectors patterns. The matrices and/or their eigenvalues and eigenvectors derived from each homologous body region can also be compared, respectively, to each other using various analytical methods and then subject to criteria established for differentiating normal from diseased states.
Published international patent application, PCT/CA01/01788, discloses a breast electrode array for diagnosing the presence of a disease state in a living organism, wherein the electrode array comprises a flexible body, a plurality of flexible arms extending from the body, and a plurality of electrodes provided by the plurality of flexible arms, wherein the electrodes are arranged on the arms to obtain impedance measurements between respective electrodes. In one embodiment, the plurality of flexible arms are spaced around the flexible body and are provided with an electrode pair. In operation, the electrodes are selected so that the impedance data obtained will include elements of an impedance matrix, plus other impedance values that are typically obtained with tetrapolar impedance measurements. In a preferred embodiment the differences between corresponding homologous impedance measurements in the two body parts are compared in variety of ways that allow the calculation of metrics that can serve either as an indicator of the presence of disease or localize the disease to a specific breast quadrant or sector. The impedance differences are also displayed graphically, for example in a frontal plane representation of the breast by partitioning the impedance differences into pixel elements throughout the plane. These pixel plots as well can be used to define a set of metrics for cancer detection, for example by using the difference between homologous pixels of two body parts.
This invention provides for an improved breast electrode array and method of analysis for detecting and diagnosing diseases, particularly using the improved electrode array of this invention.
In particular, an electrode array for diagnosing the presence of a disease state in a living organism is disclosed, with the electrode array comprising a body, a plurality of flexible arms extending from the body, and a plurality of outer electrodes provided by the plurality of flexible arms, and a plurality of inner electrodes provided on at least one of the flexible arms and positioned partway between the body and the outer electrodes, and wherein the outer electrodes and the inner electrodes are arranged on the arms to obtain impedance measurements between respective electrodes.
In another aspect of this invention, the electrode array comprises a body, a plurality of flexible arms extending from the body, and a plurality of outer electrodes provided by the plurality of flexible arms, the outer electrodes arranged on the arms to obtain impedance measurements between respective electrodes and with at least one of the outer electrodes spaced from the body greater than the other outer electrodes.
In particular, at least a further one of the outer electrodes is spaced from the body greater than the other outer electrodes but not as great as said at least one outer electrode. the further outer electrode is provided on a flexible arm adjacent to a flexible arm having the at least one outer electrode.
Further, the outer electrodes are arranged in electrode pairs, and each of the plurality of arms is provided with an electrode pair. Similarly, the inner electrodes can be arranged in electrode pairs.
In a further aspect of the invention, at least one of the inner electrodes is spaced from the body greater than the other inner electrodes, and the at least one inner electrode is provided on the flexible arm having the at least one outer electrode.
The electrode array can also feature the plurality of flexible arms spaced around the body.
In a further aspect of the invention, the electrode array has the at least one outer electrode comprising a first set of electrodes having at least one electrode on each of two adjacent flexible arms. More particularly, the electrode array has the outer electrodes provide for a second set of electrodes spaced from the body greater than the other outer electrodes but not as great as the first set of electrodes, and the second set of electrodes has at least one electrode on each of two flexible arms, and the flexible arms are each adjacent to one of the flexible arms that has the first set of electrodes. A third set of electrodes are spaced from the body greater than the other outer electrodes but not as great as the second set of electrodes, and the third set of electrodes has at least one electrode provided on one flexible arm, and that flexible arm is adjacent to one of the flexible arms that has the second set of electrodes. Moreover, a fourth set of electrodes are spaced from the body greater than the other outer electrodes but not as great as the third set of electrodes, and the fourth set of electrodes has at least one electrode on each of two flexible arms, and one of the flexible arms is adjacent the flexible arm that has the third set of electrodes, and the other of said flexible arms is adjacent one of the flexible arms that has the second set of electrodes. The remaining of the other outer electrodes are equally spaced from the body not as great as the fourth set of electrodes.
The inner electrodes can be provided on at least one of the flexible arms and positioned partway between the body and the outer electrodes, and with at least one of the inner electrodes spaced from the body greater than the other inner electrodes and provided on one of the flexible arms having the first set of electrodes. Moreover, at least one of the other inner electrodes is provided on one of the flexible arms having the second set of electrodes, but not adjacent to the flexible arm having the at least one inner electrode, and at least one of the other inner electrodes is provided on the flexible arm having the third set of electrodes, and with this flexible arm not adjacent the flexible arm having both the second set of electrodes and said other inner electrodes. Further at least one of the other inner electrodes is provided on at least one other flexible arm that is not adjacent to any of the flexible arms that have the first, second, third, and fourth set of electrodes. The other inner electrodes are equally spaced from the body.
In one aspect of the invention certain of the flexible arms are of different lengths to provide for the spacing of the different sets of electrodes.
Moreover, at least one the flexible arms is transparent and is provided with a marker along the central axis of the flexible arm. The marker is a line along the central axis of the flexible arm. The flexible arm with the marker is provided with a tab at its end thereof.
In further aspect of this invention, a system for diagnosing the possibility of disease in a body part is disclosed. The system comprises an electrode array of this invention containing a plurality of outer electrodes and at least one inner electrode capable of being electrically coupled to the body part, a controller switching unit, and a multiplexing unit. The controller switching unit and multiplexing unit allow a current to flow between any two electrodes and a resultant voltage measurement to be measured between any two electrodes. In particular, the controller-switching unit and the multiplexing unit allows any one of the inner electrodes and outer electrodes to be a current injection electrode, and allows any one the inner electrodes and outer electrodes to be a voltage measurement electrode. In one aspect of the invention, the controller-switching unit and the multiplexing unit select the current injection electrodes and the voltage measurement electrodes such that a tetrapolar measurement is taken between any two pairs of inner electrodes, any two pairs of outer electrodes, and any two pairs of electrodes with one selected from the pairs of outer electrodes and one selected from the pairs of inner electrodes.
A template for positioning an electrode array on a part of a living organism to be diagnosed for the presence of a disease state is also disclosed. The template comprises an elongate body, and a mark provided over at least part of the length of the body, and wherein the elongate body has an opening therein and is provided with at least one hole spaced from the opening. In a preferred use of the template to position an electrode array of this invention to a breast, the opening is sized to fit around a nipple of the breast. In particular, the elongate body has a central axis and the mark is on the central axis. The mark can be a line along the central axis of the template. The mark extends to the other end of the elongate body. The elongate body can be transparent. The opening and the at least one hole are spaced from one another along the central axis. In a preferred aspect the at least one hole is three holes.
In one aspect, the opening is provided at one end of the elongate body, and the elongate body is of sufficient length so that when the opening is fitted around the nipple of one breast the other end of the elongate body extends to at least the nipple of the other breast.
A system for positioning an electrode array on a part of a living organism to be diagnosed for the presence of a disease state is also disclosed. In particular, the system comprises a template having an elongate body, and a mark provided over at least part of the length of the body, and wherein the elongate body has an opening therein and is provided with at least one hole spaced from the opening, and an electrode array having a body, a plurality of flexible arms extending from the body, and a marker provided along the central axis of at least one of the flexible arms.
Moreover, a method of positioning an electrode array on a part of a living organism to be diagnosed for the presence of a disease state, the electrode array positioned using a template of this invention is disclosed. The method comprises:
This invention also discloses the use of an electrode array of this invention for diagnosing the presence of a disease state in a living organism, the electrode array comprising a body, a plurality of flexible arms extending from the body, a plurality of outer electrodes provided by the plurality of flexible arms, and a plurality of inner electrodes provided on at least one of the flexible arms and positioned partway between the body and the outer electrodes, the outer electrodes and the inner electrodes are arranged on the arms to obtain impedance measurements between respective electrodes, and wherein the impedance values are arranged in a mathematical matrix and mathematical analysis is performed to diagnose for the presence of a disease state.
Further, a method of diagnosing the possibility of a disease state in one of first and second substantially similar parts of a living organism is disclosed. In particular, a use of the electrode array of this invention to obtain impedance measurements through parts of a living organism is disclosed. The method and use comprises:
In particular, the pixel plot is a first pixel plot derived from the impedance measurements taken from the first area. The pixel plot can also be a second pixel plot derived from the impedance measurements taken from the second area. Moreover, the pixel plot can be a third pixel plot derived from the impedance measurements taken from between the first area and the second area. The third pixel plot can be the sum of separate pixel plots that can be derived from the impedance measurements taken from between each point in the first area and the plurality of points in the second area. The separate pixel plots that make the third pixel plot are all mapped onto a common frame of reference, and can be mapped onto a common reference plane. The common frame of reference is a set of orthogonal axes intersecting a predetermined point of the part of the living organism to be diagnosed. In particular, the common reference plane is the body frontal plane.
In one aspect, the pixel plot can be a plurality of pixel plots comprising a first pixel plot derived from the impedance measurements taken from the first area, a second pixel plot derived from the impedance measurements taken from the second area, and a third pixel plot derived from the impedance measurements taken between the first area and the second area.
In a further aspect of the invention, the plurality of pixel plots further comprise an integrated plot combining the first pixel plot, the second pixel plot, and the third pixel plot.
In a preferred use of the apparatus of this invention, the part of the living organism to be diagnosed by this method is a breast. For this application, the first area is the periareolar area of the breast and the first pixel plot is a periareolar pixel plot, the second area is the base area of the breast and the second pixel plot is a base pixel plot, and the third pixel plot is a conical pixel plot derived from impedance measurements taken from a predetermined plurality of points between the periareolar area of the breast and the base area of the breast.
For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, which show a preferred embodiment of the present invention and in which:
FIGS. 4A-D shows modes of the controller switching unit of
a, 11b, 11c, and 11d, show the four conical surfaces created by connecting the four periareolar plane electrodes to the base plane electrodes;
a, 14b, 14c, and 14d, are illustrations of the conical plane impedance chords derived from the electrode array of
a, 15b, 15c, and 15d are examples of periareolar, conical, base, and integrated pixel plots derived from this invention.
As disclosed in applicant's co-pending application Ser. No. 09/749,613, the entirety of which is incorporated herein by reference, electrical impedance is measured by using four electrodes as shown in
Impedance consists of two components, resistance and capacitive reactance (or equivalently, the magnitude of impedance and its phase angle). Both components are measured, displayed, and analyzed in the present invention. However, for the purpose of explanation of the invention, only resistance will be used and will interchangeably be referred to as either resistance or the more general term impedance.
Twelve array arms 30 are shown in the electrode array 28 of
In the embodiment illustrated, twelve electrode pairs 34 are provided around the electrode array 28, with each electrode pair 34 positioned near the outer edge of each array arm 30. The electrode pairs 34 are numbered counterclockwise for the left breast electrode array, one (1) through twelve (12), with the first electrode pair one (1) positioned near the top of
In addition an inner electrode is provided on certain of the array arms 30 of the electrode array 28. For the embodiment illustrated in
For the embodiment illustrated, electrode pairs 40 are provided on the array arms 30 that carry the electrode pairs 34 that are numbered one (1), five (5), nine (9), and eleven (11). Electrode pairs 40 are similarly numbered counterclockwise in the left breast electrode array, thirteen (13) through sixteen (16). Again, the numbering convention for the right breast electrode array is clockwise to allow for mirror-imaged electrode pairs to be compared.
Each electrode pair 40 is comprised of a current injection electrode 42 and voltage measurement electrode 44, similar to that for electrode pairs 34. For the electrode connections illustrated, the current injection electrodes 42 and the voltage measurement electrodes 44 of the electrode pairs 40 are in an opposite orientation to the current injection electrodes 36 and voltage measurement electrodes 38 of electrode pairs 34. These orientations of the electrodes maintain the required positioning of I, V, V, I (as shown in
It is to be noted, however, that the terms “current injection” and “voltage measurement” refer to the use of any four electrodes used for tetrapolar impedance measurement, with the two electrodes between which current is injected being called current injection electrodes, and the two electrodes across which voltage is measured being called voltage measurement electrodes. In particular, the present invention has the capability of interchanging which electrodes are used for current injection and voltage measurement. This allows, for example, impedance measurements to be taken between any two of electrode pairs 40, numbered thirteen (13), fourteen (14), fifteen (15) and sixteen (16), in
A diagnostic system capable of interchanging which electrodes are used for current injection and voltage measurement will now be described. Moreover, the diagnostic system is capable of tetrapolar measurements, as described above, and also of bipolar measurements where a single electrode is used for both current injection and voltage measurement. For example, current is injected between two electrodes and voltage is measured between the same two electrodes.
The system 1000 further includes a controller switching unit 260 having a first switch 280 connected to the multiplexer 160 by the first MX lead 180 and the second MX lead 200, a second switch 300 connected to the multiplexer 160 by the third MX lead 220 and the fourth MX lead 240, a current input lead 320 connected to the first switch 280, a current output lead 340 connected to the second switch 300, a first voltage lead 360 connected to the first switch 280, and a second voltage lead 380 connected to the second switch 300. The controller switching unit 260 also includes a controller 390. The system 1000 further includes an impedance module 400 and a diagnosis module 420.
Also shown in
The N body leads 120 electrically connect the multiplexing unit 140 to the body part 110. Each of the N body leads 120 includes a wire capable of carrying a current and an electrode to attach to the body part 110. A current conducting gel can act as an interface between the electrode and the skin covering the body part 110.
The multiplexing unit 140 and the controller switching unit 260 allow a current to flow through the body part 110 between any two body leads, n1 and n2, of the N body leads 120, and a resultant voltage to be measured between any two body leads, n3 and n4 of the N body leads 120, where n1≠n2 and n3≠n4, but where n1, n2, n3 and n4 need not otherwise be distinct. Thus, n1, n2, n3 and n4 are numbers belonging to the set {1, 2, . . . , N} that identify body leads. For example, if n1=7, then n1 denotes the seventh body lead from among the N body leads 120 used to inject current into the body part 110.
The impedance module 400 generates current that is injected into the current input lead 320 and then delivered to the body part. The current output lead 340 receives the current from the body part. When the current is traveling through the body part, the first voltage lead 360 and the second voltage lead 380 are used to measure the resultant voltage between these leads 360 and 380. The impedance module 400 uses this voltage, together with the known current injected into the current input lead 320, to calculate corresponding impedance, which may then be used by the diagnosis module 420 to diagnose disease.
In one embodiment, N is even and the multiplexer 160 can electrically connect the first MX lead 180 and the fourth MX lead 240 to a first set of N/2 of the N leads, and the second MX lead 200 and the third MX lead 220 to a second set of the other N/2 leads. In a conventional system, the first set of N/2 leads are exclusively used to inject current into and receive current from the body part. The second set of N/2 leads are then exclusively used to measure resultant voltages in tetrapolar measurements. This configuration limits the number of impedances that can be measured.
In the system 1000, however, the second set of N/2 leads can also be used to inject and receive current, and the first set can be used to measure resultant voltages. Thus, the system 1000 can furnish a greater number of impedances. Moreover, as detailed below, the system can make both tetrapolar and bipolar measurements. The added benefits arise from the functionality of the controller switching unit 260. By using the controller switching unit 260, the system 1000 can force current to flow through the body part 110 between any two body leads, n1 and n2, of the N body leads 120, and a resultant voltage to be measured between any two body leads, n3 and n4 of the N body leads 120, where n1≠n2 and n3≠n4.
FIGS. 4A-D show several states of the switches 280 and 300 resulting in different modes of the controller switching unit 260 of the system of
In
In
In a tetrapolar mode, the current input lead 320 is electrically connected to exactly one of the first MX lead 180 and the second MX lead 200 and the first voltage lead 360 is electrically connected to the other one of the first MX lead 180 and the second MX lead 200; likewise, the current output lead 340 is electrically connected to exactly one of the third MX lead 220 and the fourth MX lead 240 and the second voltage lead 380 is connected to the other one of the third MX lead 220 and the fourth MX lead 240.
The two tetrapolar modes shown in
In
In
In
In a bipolar mode, the current input lead 320 and the first voltage lead 360 are electrically connected to each other and to exactly one of the first MX lead 180 and the second MX lead 200, and the current output lead 340 and the second voltage lead 380 are electrically connected to each other and to exactly one of the third MX lead 220 and the fourth MX lead 240.
The two modes shown in
In addition to the tetrapolar and bipolar modes shown in
In
From
In particular, current is generated by the impedance module 400 and sent to the current input lead 320. From there, the current travels to the first MX lead 180 via the first switch 280 and from there to the electrode 6 via the multiplexer 160. The current next travels through the body part 110 (such as, for example, a breast) to the electrode 9 and then through the multiplexer 160 to the fourth MX lead 240. The current then flows to the current output lead 340 via the second switch 300 and then back to the impedance module 400. The resultant voltage is measured between the first and second voltage leads 360 and 380, which corresponds to the voltage between the electrodes 2 and 5. The first voltage lead 360 is connected to the electrode 2 via the first switch 280 and the multiplexer 160, and the second voltage lead 380 is electrically connected to the electrode 5 via the second switch 300 and the multiplexer 160. The controller 390 controls the states of the switches 280 and 300 and the multiplexing states in the multiplexer 160 that determine through which leads current flows and which leads are used to measure voltage.
The first body part multiplexer 520 is used for multiplexing electrical signals to the first body part of the homologous pair. In particular, the first body part A multiplexer unit 540 and B multiplexer unit 560 are both capable of multiplexing current and voltage signals to and from the N leads 120. Likewise, the second body part multiplexer 580 is used for multiplexing electrical signals to the homologous body part. In particular, the second body part A multiplexer unit 600 and B multiplexer unit 620 are both capable of multiplexing current and voltage signals to and from the N leads 120, as described below.
A similar binary code for the multiplexers 680 and 700 dictates through which one of the first 16 electrodes of the 32 leads 120 current is received from the breast, provided the states of the switches 280 and 300 connect the current output lead 340 to the fourth MX lead 240. If the fourth MX lead 240 is not connected to the current output lead 340, but is connected to the second voltage lead 220, then the fourth MX lead 240 is used for measuring the resultant voltage, provided the inhibit state of the multiplexer 680 or the multiplexer 700 is off.
The B multiplexer unit 560 is similar to the A multiplexer unit 540 in that it has four one-to-N/4 multiplexers analogous to 640, 660, 680 and 700. However, the one-to-N/4 multiplexers are capable of connecting with the second and third MX leads 200 and 220, instead of the first and fourth MX leads 180 and 240. Here, the inhibit and control states determine which electrode from among the other N/2 electrodes is used to deliver current or measure voltage.
Thus, by setting inhibit and control states, in coordination with the states of the switches 280 and 300, it is possible to direct current between any pair of the N leads 120 and to make a measurement of the resultant voltage between any pair of the N leads 120.
The inhibit and control states are set by the controller 390 with a shift-register and/or a computer. A direct digital stream can be sent to the shift register for this purpose.
The function of the second body part multiplexer 580 is analogous to that of the first body part multiplexer 520 and therefore need not be described further.
Using the first switch 280 and the second switch 300, the internal load 840 can be connected to the impedance module 400 in a tetrapolar mode or in a bipolar mode. The internal load 840 has a known impedance and therefore can be used to test the diagnostic system 820.
Additionally, the internal load 840 can be used to change the measurement range of the system 820. By attaching this internal load 840 in parallel with any load, such as the body part 110, the system 820 is capable of measuring larger impedances than would otherwise be possible. If the resistance of the internal load 840 is Rint and is in parallel, the measured resistance R is given by R=(1/Rload+1/Rint)−1 where Rload is the resistance of the load. Consequently, the measured resistance is reduced from the value without the internal load, thereby increasing the measurement range of the system 840.
The switches 280 and 300 allow current to flow between various pairs of electrodes on a body part, and resultant voltage to be measured between various pairs of electrodes, as described above with reference to
The switches 920 and 940 can be turned on or off and can be used to make tetrapolar and bipolar measurements. With only one of the switches 920 and 940 on, a tetrapolar measurement can be made. With both switches 920 and 940 on, a bipolar measurement can be made. For example, when the first switch 920 is on, and the second switch is off, the resultant functionality corresponds to that of
In another example, when the first switch 920 is off, and the second switch 940 is on, the resultant functionality corresponds to that of
In yet another example, the first and second switches 920 and 940 are both on, which corresponds to
The controller switching unit 900 also includes an internal load switch 1080 that is connected to the internal load 840. The controller switching unit 900 and the internal load 840 are used to test the system and to increase the measurement range, as described above.
Referring again to
In addition, certain inner electrode pairs 40 can be spaced from body 32 at different positions along array arms 30. For the embodiment illustrated in
It can therefore be appreciated that the resultant array shape illustrated in
It can be appreciated that different array sizes can be produced to accommodate different breast sizes. For different sizes of electrode arrays as illustrated in
Array arm 45—numbered four (4) in
Prior to application of the breast electrode arrays, a template is used to position the electrode arrays. As illustrated in
Identical positioning of left and right breast electrode arrays is assured by centering the body 32 of the array over the nipple, then with the nipple as the pivot point for rotation, bringing tab line 47 over the previously placed skin alignment mark. This process is facilitated by the presence of tab 46 because (1) it allows the operator to see tab line 47 while still grasping the end of array arm 45, and (2) performing the rotation of the array at the end of the arm rather than at the body 32 reduces adjustment overshoot during the alignment process.
With the exception of the above differences, the construction of electrode array 28 is as described in applicant's co-pending application Ser. No. 09/749,613, which is incorporated herein by reference.
One technique for screening and diagnosing diseased states within the body using electrical impedance is disclosed in U.S. Pat. No. 6,122,544, and in co-pending application Ser. No. 09/749,613, which are incorporated herein by reference. In U.S. Pat. No. 6,122,544 data are obtained in organized patterns from two anatomically homologous body regions, one of which may be affected by disease. One subset of the data so obtained is processed and analyzed by structuring the data values as elements of an impedance matrix. The matrices can be further characterized by their eigenvalues and eigenvectors. These matrices and/or their eigenvalues and eigenvectors can be subjected to a pattern recognition process to match for known normal or disease matrix or eigenvalue and eigenvectors patterns. The matrices and/or their eigenvalues and eigenvectors derived from each homologous body region can also be compared, respectively, to each other using various analytical methods and then subject to criteria established for differentiating normal from diseased states.
In co-pending application Ser. No. 09/749,613, electrodes are selected so that the impedance data obtained can be considered to represent elements of an impedance matrix. Then two matrix differences are calculated to obtain a diagnostic metric from each. In one, the absolute difference between homologous right and left matrices, on an element-by-element basis, is calculated; in the second, the same procedure is followed except relative matrix element difference is calculated. These techniques as disclosed above can be applied utilizing the electrode array of the present invention, for example, electrode array 28 illustrated in
Breast electrode array 28, as constructed, is flat, but the arms are flexible, so that when applied to the breast the array shape becomes approximately a section of a sphere. It can be appreciated therefore that by placing certain of the electrodes pairs 40 at some intermediate location along array arm 30 that they will be at a different topology from electrode pairs 34. For the electrode array 28 illustrated in
It is known that electrical current does not flow in a single or in a straight path through tissue. However, for purposes of the following analyses, it will be assumed it does. Because many of these analyses are based on comparison of homologous (mirror image) small areas (pixels) in each breast, the potential inaccuracies that could result from the above assumption will tend to be negligible. Therefore, current flow, and subsequent impedance measurement between electrode pairs can be represented as straight lines, or chords, connecting the two pairs.
From
In particular,
Co-pending application Ser. No. 09/749,613, which is incorporated herein by reference, describes a pixel plot method of data analysis for detecting the possible presence of a breast cancer. The breast electrode array that was subject of this application was circular in shape, and consisted of 16 equal length arms, each with an electrode pair close to the end of the arm. All impedance chords were, therefore, in the same plane (body frontal plane) and were represented as chords of a circle in the frontal plane. The circle was divided into equal size quadrants by orthogonal axes intersecting at the nipple. Briefly, pixel analysis consisted of subdividing the plane into a grid of square-shaped pixel elements, and calculating the impedance value of each pixel element from the number of impedance chords that pass through the pixel, the impedance magnitude of each such impedance chord, and the segment length of the chord within the pixel element. A pixel difference set was created by subtracting the pixel impedance values of homologous (mirror image) pixel elements in the right and left breasts. Analysis included calculating difference metrics from the means and sums of all of the difference values, and comparing to a pre-established difference threshold to diagnose the possibility of a disease state. Pixel difference sets can also be plotted (pixel plots) and be divided into sectors, with the sector displaying the largest difference being the likely location of a cancer for those sets where the calculated difference metric exceeds a threshold value.
The present invention generates three sets of pixel plots based on the method described above from application Ser. No. 09/749,613, one from each of the base, conical, and periareolar planes. However, as previously indicated, there are four separate conical surfaces, each defining impedance chords that can be projected onto the frontal plane, as shown in
It is also desirable to have a single, integrated pixel plot that combines base, conical, and periareolar pixel plots. This again would use an additive model where the base, conical, and periareolar plots are added. This single integrated pixel plot forms a fourth pixel plot.
a, 15b, 15c, and 15d are illustrative examples of pixel plots of this invention obtained from a normal subject. Pixel plots 100a, 100b, 100c, and 100d are periareolar, conical, base, and integrated pixel plots, respectively. Note that each consists of right (R) and left (L) breast pixel difference plots, with the magnitude of difference indicated here by a gray scale, with white or blank being no difference and black being maximum difference for a given plot. Following the convention of co-pending application Ser. No. 09/749,613, for any given pixel location, the value is plotted on the side having the lower value, or if there is no difference, the pixel area is left white or blank on both sides. Whereas the illustrated example of the present invention is a novel and improved apparatus and method for detecting and locating breast cancers, the invention can also be applied to other diseases or conditions in which there is a distinguishable difference in electrical impedance in the tissue as a result of the disease or condition.
It can be appreciated that variations to this invention would be readily apparent to those skilled in the art, and this invention is intended to include those alternatives.
This application is a division of application Ser. No. 10/724,357, filed Dec. 1, 2003. This application also claims the benefit of Provisional Application No. 60/429,560, filed Nov. 29, 2002, the entire contents of each of which are hereby incorporated by reference in this application.
Number | Date | Country | |
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Parent | 10724357 | Dec 2003 | US |
Child | 11896532 | Sep 2007 | US |