Electromagnetic bone-assessment apparatus and method
First Claim
1. Apparatus for non-invasive quantitative evaluation of the status of bone tissue in vivo, as measured in a selected bony member of a living body and manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
circuit means including a pair of spaced magnetic field coils wherein the spacing is adapted to receive the bony member to be analyzed and wherein said circuit means is a two-port electrical circuit,network analyzer means included in said circuit means for obtaining a set of three (3) inductively-determined two-port frequency-dependent bone-admittance functions when said circuit means includes said bony member;
means for selectively using said pair of magnetic field coils and said network analyzer with a medium of known electrical and magnetic properties and path length to thereby establish a set of three (3) inductively-determined two-port frequency-dependent reference-admittance functions, and including means to store each of said reference-admittance functions, andmeans for comparatively evaluating said bone-admittance functions and reference-admittance functions, whereby to estimate one or more of the said quantities.
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Accused Products
Abstract
Non-invasive quantitative in-vivo electromagnetic evaluation of bone is performed by subjecting bone to an electrical excitation wave-form supplied to a pair of electrodes on opposite sides of a bony member, and involving a repetitive finite duration signal consisting of plural frequencies that are in the range 0 Hz-200 MHz. Signal-processing of a bone-current response signal and a bone-voltage response signal is operative to sequentially average the most recently received given number of successive bone-current and bone-voltage response signals to obtain an averaged per-pulse bone-current signal and an averaged per-pulse bone-voltage signal, and to produce their associated Fourier transforms. These Fourier transforms are further processed to obtain the frequency-dependent bone-admittance function. In a separate operation, the same electrodes respond to the same excitation signal via a medium of known electromagnetic properties and path length to establish a reference-voltage signal and reference-current signal, which are processed to produce their associated Fourier transforms. These two Fourier transforms are further processed to produce a frequency-dependent reference-admittance function, which together with the bone-admittance function are processed to derive the frequency-dependent bone-conductivity real function, σ'"'"'b (f), and frequency-dependent dielectric bone-permittivity real function, .di-elect cons.'"'"'b (f). The function σ'"'"'b (f) is related to the energy loss in the bony member, and the function .di-elect cons.'"'"'b (f) is related to the energy storage in the bony member. A neural network, configured to generate an estimate of one or more of the desired bone-related quantities, is connected for response to the functions σ'"'"'b (f) and .di-elect cons.'"'"'b (f), whereby to generate the indicated estimates of bone status, namely, bone-density, bone-architecture, bone-strength and bone-fracture risk.
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Citations
12 Claims
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1. Apparatus for non-invasive quantitative evaluation of the status of bone tissue in vivo, as measured in a selected bony member of a living body and manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
circuit means including a pair of spaced magnetic field coils wherein the spacing is adapted to receive the bony member to be analyzed and wherein said circuit means is a two-port electrical circuit, network analyzer means included in said circuit means for obtaining a set of three (3) inductively-determined two-port frequency-dependent bone-admittance functions when said circuit means includes said bony member; means for selectively using said pair of magnetic field coils and said network analyzer with a medium of known electrical and magnetic properties and path length to thereby establish a set of three (3) inductively-determined two-port frequency-dependent reference-admittance functions, and including means to store each of said reference-admittance functions, and means for comparatively evaluating said bone-admittance functions and reference-admittance functions, whereby to estimate one or more of the said quantities. - View Dependent Claims (11)
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
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2. Apparatus for non-invasive quantitative evaluation of the status of bone tissue in vivo, as measured in a selected bony member of a living body and manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
circuit means including a pair of spaced magnetic field coils wherein the spacing is adapted to receive the bony member to be analyzed and wherein said circuit means is a two-port electrical circuit, network analyzer means included in said circuit means for obtaining a set of three (3) inductively-determined two-port frequency-dependent bone-admittance functions when said circuit means includes said bony member, and means for comparatively evaluating said bone-admittance functions, whereby to estimate one or more of the said quantities.
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
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3. Apparatus for non-invasive quantitative evaluation of the status of bone tissue in vivo, as measured in a selected bony member of a living body and manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
circuit means including a pair of spaced magnetic field coils wherein the spacing is adapted to receive the bony member to be analyzed and wherein said circuit means is a two-port electrical circuit, network analyzer means included in said circuit means for obtaining a set of three (3) inductively-determined two-port frequency-dependent bone-admittance functions when said circuit means includes said bony member; means for selectively using said pair of magnetic field coils and said network analyzer with a medium of known electrical and magnetic properties and path length to thereby establish a set of three (3) inductively-determined two-port frequency-dependent reference-admittance functions, and including means to store each of said reference-admittance functions, and means including a neural network connected for response to said bone-admittance functions and reference-admittance functions, said neural network being configured to generate an estimate of one or more of the said quantities. - View Dependent Claims (7, 9, 10)
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
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4. Apparatus for non-invasive quantitative evaluation of the status of bone tissue in vivo, as measured in a selected bony member of a living body and manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
circuit means including a pair of spaced magnetic field coils wherein the spacing is adapted to receive the bony member to be analyzed and wherein said circuit means is a two-port electrical circuit, network analyzer means included in said circuit means for obtaining a set of four (4) inductively-determined two-port frequency-dependent bone-admittance functions when said circuit means includes said bony member, and means including a neural network connected for response to said bone-admittance functions, said neural network being configured to generate an estimate of one or more of the said quantities. - View Dependent Claims (8)
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
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5. Apparatus for non-invasive quantitative evaluation of the status of bone tissue in vivo, as measured in a selected bony member of a living body and manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
circuit means including a pair of spaced magnetic field coils wherein the spacing is adapted to receive the bony member to be analyzed and wherein said circuit means is a two-port electrical circuit, network analyzer means included in said circuit means for obtaining a set of three (3) inductively-determined two-port frequency-dependent bone-admittance functions when said circuit means includes said bony member; means for selectively using said pair of magnetic field coils and said network analyzer with a medium of known electrical and magnetic properties and path length to thereby establish a set of three (3) inductively-determined two-port frequency-dependent reference-admittance functions, and including means to store each of said reference-admittance functions; additional circuit means including a pair of spaced electrodes wherein the spacing is adapted to receive the bony member to be analyzed and wherein said additional circuit means is a two-terminal electrical circuit, impedance analyzer means included in said additional circuit means for obtaining a capacitively-determined frequency-dependent bone-admittance function when said additional circuit means includes said bony member; means for selectively using said pair of electrodes and said impedance analyzer with an additional medium of known electrical and magnetic properties and path length to thereby establish a capacitively-determined frequency-dependent reference-admittance function, and including means to store said reference-admittance function, and means for comparatively evaluating said capacitively-determined bone-admittance function and stored reference-admittance function, and said inductively-determined bone-admittance function and stored reference-admittance function whereby to estimate one or more of the said quantities.
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
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6. Apparatus for non-invasive quantitative evaluation of the status of bone tissue in vivo, as measured in a selected bony member of a living body and manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
circuit means including a pair of spaced magnetic field coils wherein the spacing is adapted to receive the bony member to be analyzed and wherein said circuit means is a two-port electrical circuit, network analyzer means included in said circuit means for obtaining a set of three (3) inductively-determined two-port frequency-dependent bone-admittance functions when said circuit means includes said bony member; additional circuit means including a pair of spaced electrodes wherein the spacing is adapted to receive the bony member to be analyzed and wherein said additional circuit means is a two-terminal electrical circuit, impedance analyzer means included in said additional circuit means for obtaining a capacitively-determined frequency-dependent bone-admittance function when said additional circuit means includes said bony member, and means for comparatively evaluating said capacitivly-determined bone-admittance function and said inductively-determined bone-admittance function whereby to estimate one or more of the said quantities.
- bone-mineral density, architecture, strength and fracture risk at a given time, said apparatus comprising;
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12. The method of non-invasively and quantitatively evaluating the status of bone tissue in vivo, as manifested through one or more of the quantities:
- bone-mineral density, architecture, strength and fracture risk, using two magnetic field coils that are spaced to receive a bony part of a living body, which method comprises the steps of;
(a) electrically coupling said magnetic field coils to nearby skin on opposite sides of said bony part, and whereby said magnetic field coils and bony part comprise a two-port electrical network; (b) connecting a network analyzer to the said two-port electrical network, whereby to obtain a set of three (3) inductively-determined two-port frequency-dependent bone-admittance functions associated with said two-port electrical network; and (c) comparatively evaluating the set of three (3) two-port bone-admittance functions.
- bone-mineral density, architecture, strength and fracture risk, using two magnetic field coils that are spaced to receive a bony part of a living body, which method comprises the steps of;
Specification