Ultrasound method and apparatus for evaluating, in vivo, bone conditions

A method of assessing the condition of a bony member of a patient comprising the steps of:

• a. launching into the patient an ultrasound signal containing energy components at frequencies in a spectrum from about 100 kHz to about 3.0 MHz, such pulse being launched at a first position proximate the surface of a bony member which is surrounded by minimal soft tissue;
• b. proximate a second position on the surface of said bony member, monitoring said ultrasound spectrum, and generating electrical signals, termed "received signals" corresponding to the energy in said monitored ultrasound spectrum;
• c. extracting from the received signals the components thereof at frequencies greater than a first predetermined frequency, to provide a time-domain high frequency signal, and the components thereof at frequencies less than a second predetermined frequency, to provide a time-domain low frequency signal;
• and
• d. comparing the time-domain low frequency signal to the launched ultrasound signal, to provide an indicator of condition of the bony member.

A method of accessing the condition of a bony member of a patient comprising the steps of:

• a. launching into a first position proximate the surface of a bony member of the patient an ultrasound signal, such bony member being surrounded by minimal soft tissue;
• b. at a second position proximate the surface of said bony member, monitoring the spectrum of the ultrasound signal, and generating electrical signals corresponding to the energy in said monitored spectrum, each such electrical signal having a waveform associated therewith;
• c. said first and second positions substantially opposing each other on the surface of the bony member;
• d. comparing with a catalog of sets of waveform characteristics from a representative sample of the general public including for each age range a spectrum of bone conditions, at least one selected waveform characteristic of the generated electrical signals;
• e. selecting from said catalog that set of waveform characteristics which most closely matches the at least one selected waveform characteristic of the generated electrical signals;
• and
• f. determining the condition of the patient's bony member by comparing the age and bone condition represented by the matched catalog set of waveform characteristics with the patient's age.

A method for evaluating the bone condition of a patient comprising the steps of:

• a. providing an apparatus including (i) first transducer means for launching a broad band acoustic signal, said first transducer means having a launching face;
• (ii) second transducer means for monitoring excitation in said frequency range, said second transducer means having a receiving face;
• (iii) positioning means for locating the launching face of the first transducer means and the receiving face of the second transducer means on opposite sides of a bony member of the patient, said bony member possibly being surrounded by soft tissue;
• (iv) signal generator means for exciting the first transducer means to launch an acoustic signal in said range;
• (v) a data acquisition system electronically connected to said signal generator means and to said second transducer means, said data acquisition system being capable of recording signals corresponding to the time variation of acoustic excitation at the second transducer means;
• and (vi) electronic data computation means for processing the recorded data;
• b. generating an acoustic signal with said signal generator and launching said acoustic signal from said launching transducer means into the bony member;
• c. monitoring acoustic excitation at the second transducer means and sending to the data acquisition system a signal corresponding to the monitored excitation;
• d. recording the history of the monitored excitation with respect to time, with the data acquisition system;
• e. providing an electronic template signal for comparison with the recorded time-varying history of the monitored excitation;
• f. maximizing a cross-correlation function between the signal corresponding to the monitored excitation and the template signal, to minimize the effect of noise in obscuring the record of the time of arrival at the second transducer means of the acoustic signal;
• g. determining the time of arrival of the acoustic signal response at the receiving transducer means, and from said time and the time of pulse launching, the duration of travel of the acoustic signal through the bone and soft tissue;
• h. measuring the distance through which the acoustic signal travels between the first and second transducer means;
• i. computing the velocity of the acoustic signal through the bony member and surrounding soft tissue by dividing the measured distance by the computed arrival time;
• j. normalizing the velocity with respect to the patient's soft tissue characteristics, by applying an appropriate soft tissue normalization factor;
• k. comparing the normalized velocity to a statistical representation of normalized velocities for different groups of the population, grouped according to their age and bone condition;
• and
• l. responsive to such comparison, indicating the bone condition of the patient.

A method of assessing the bone condition of a patient comprising the steps of:

• a. launching into a first position proximate the surface of a bony member of the patient an ultrasound signal having a spectrum containing energy in the frequency range of about 100 kHz to about 3 MHz, such bony member being surrounded by minimal soft tissue;
• b. at a second position proximate the surface of said bony member, monitoring acoustic excitation due to said ultrasound signal, generating electrical signals corresponding to said excitation and recording such signals with the data acquisition system;
• c. measuring the distance between the first and second positions;
• d. determining the transit time of the ultrasound signal from the first position to the second position;
• e. responsive to said measuring step and said transit-time-determining step, determining the velocity of the ultrasound signal components travelling through the bony member and surrounding minimal soft tissue;
• f. computing from such velocity a compensated velocity adjusted to account for the effects of signal propagation through soft tissue surrounding the bony member;
• and
• g. determining the patient's bone condition from the compensated velocity.

Apparatus for evaluating the condition of a bony member of a patient comprising:

• a. means for launching into the patient at a first position proximate a bony member transdermally, for transmission through such bony member and any surrounding soft tissue, an ultrasound signal containing energy components in an ultrasound spectrum from about 100 kHz to about 3.0 MHz;
• b. means for monitoring the spectrum of ultrasound signals arriving at a second position proximate such bony member, and for generating electrical signals (termed "received signals") corresponding to the energy in said monitored ultrasound spectrum;
• c. means for extracting from the received signals (i) the components thereof at frequencies greater than a first predetermined frequency and providing a time-domain high frequency signal, and (ii) the components thereof at frequencies less than a second predetermined frequency and providing a time-domain low frequency signal;
• and
• d. means for comparing the time-domain high frequency signal to the time-domain low frequency signal to provide an indicator of the condition of the bony member.

Apparatus for evaluating the condition of a bony member of a patient comprising:

• a. means for launching into the patient, for transmission through a bony member and any surrounding soft tissue, an ultrasound signal containing energy components in an ultrasound spectrum from about 100 kHz to about 3.0 MHz;
• b. means for monitoring energy in said ultrasound spectrum arriving at a second surface of said bony member, substantially opposing said first surface, and for generating electrical signals (termed "received signals") corresponding to the energy in said monitored ultrasound spectrum;
• c. means for extracting from the received signals the components thereof at frequencies less than a predetermined frequency and providing a time-domain low frequency signal;
• and
• d. means for comparing the time-domain low frequency signal to the launched ultrasound signal to provide an indicator of condition of the bony member.

Apparatus for assessing the condition of a bony member of a patient comprising:

• a. means for launching into the patient, at a first position proximate a bony member, an ultrasound pulse containing energy components in a spectrum from about 100 kHz of about 3.0 MHz;
• b. a data acquisition system;
• c. at a second position proximate the bony member, substantially opposing said first surface, means for monitoring said ultrasound spectrum, and for generating and supplying to the data acquisition system, for recording thereby, electrical signals corresponding to the energy in the monitored spectrum;
• d. means for comparing with a catalog of waveform characteristics from a representative sample of the general public, including for each age range a spectrum of bone conditions, at least one selected waveform characteristic of said electrical signals and for selecting from said catalog that set of waveform characteristics which most closely matches the at least one selected waveform characteristic of the electrical signals;
• and
• e. means for determining the condition of the patient's bone by comparing the age and bone condition represented by the matched catalog set of waveform characteristics with the patient's age.

Apparatus for evaluating the bone condition of a patient, comprising:

• a. means for launching into the patient at a first position proximate a bony member an ultrasound signal having energy components from about 100 kHz to about 3 MHz, such bony member possibly being surrounded by minimal soft tissue;
• b. means for monitoring acoustic excitation at a second position proximate said bony member, and for generating electrical signals corresponding to said excitation;
• c. the data acquisition system being adapted to record said electrical signals;
• d. measuring means for measuring the distance between the first and second position;
• e. velocity-determining means responsive to the electrical signals and to the measuring means, for determining the velocity of the ultrasound energy components travelling through the bony member;
• and
• f. means responsive to the velocity-determining means, for determining the patient's bone condition from the velocity through the bony member.

Apparatus for evaluating the bone condition of a patient, comprising:

• a. means for launching an acoustic signal having energy components in the range between about 100 kHz and about 3.0 MHz, said means having a launching face;
• b. means for monitoring excitation in said frequency range, said means having a receiving face;
• c. positioning means for locating said first and second transducer means on opposite sides of a bony member of the patient, said bony member being surrounded by soft tissue;
• d. signal generator means for triggering the launching transducer means to launch an acoustic signal from the launching face thereof;
• e. a data acquisition system electronically connected to said signal generator means and to said monitoring means, said data acquisition system being adapted
• (1) to determine and record the time at which an acoustic signal is launched;
• (2) to monitor and record with respect to time acoustic excitation signals from the monitoring means;
• and
• (3) to record the history of the averaged monitored excitation with respect to time;
• f. electronic data computation means for processing the recorded data, such computation means
• (1) comparing an electronic template signal with said recorded averaged time-varying history of said monitored excitation;
• (2) maximizing a cross-correlation function between said signal corresponding to said averaged monitored excitation and said template signal, to minimize the effect of noise in obscuring the record of the time of arrival of the acoustic signal at said monitoring means;
• (3) determining the time of arrival of said averaged signal response at said monitoring means, and from said time, the duration of travel of said averaged signal through the bone and soft tissue;
• g. means for measuring the distance through which an acoustic signal travels between the launching face and the receiving face and for providing to the computation means a signal representing such measurement;
• and
• h. the computation means further
• (4) computing the average velocity of the signals through the bony member and surrounding soft tissue by dividing the measured distance by the computed arrival time;
• (5) adjusting the velocity with respect to the patient's soft tissue characteristics, by applying an appropriate soft tissue adjustment factor;
• (6) comparing the adjusted velocity to a statistical representation of adjusted velocities for different groups of the population, grouped according to their age and osteoporotic health;
• and
• (7) responsive to such comparison, generating a probabilitistic evaluation of the bone condition of the patient.

Apparatus for evaluating the bone condition of a patient, comprising:

• a. means for launching into a first position on the surface of a selected bone of the patient, an acoustic signal containing energy components in the frequency range between about 1.5 and about 3.0 MHz;
• b. means for monitoring excitation transmitted through the patient's bone to a second position on the surface thereof, responsive to said pulse;
• c. a data acquisition system electronically connected to said means for launching and to said means for means for monitoring, said data acquisition system being adapted
• (1) to determine and record the time at which a such signal pulse is launched;
• and
• (2) to record with respect to time acoustic excitation signals from the monitoring means;
• d. electronic data computation means for processing the recorded data, such computation means
• (1) comparing an electronic template signal with said recorded time-varying history of said monitored excitation;
• (2) maximizing a cross-correlation function between said signal corresponding to said monitored excitation and said template signal, to minimize the effect of noise in obscuring the record of the time of arrival of the pulse at the monitoring means;
• and
• (3) determining the time of arrival of said signal response at said monitoring means, and from said time, the duration of travel of said signal through the bone and soft tissue;
• e. means for measuring the distance through which an acoustic signal travels between the launching means and the monitoring means and for providing to the computation means a signal representing such measurement;
• and
• f. the computation means further
• (4) computing the velocity of the acoustic signal through the bony member and surrounding soft tissue, responsive to said distance measurement signal, by dividing the measured distance by the duration of travel of the acoustic signal;
• (5) adjusting the velocity with respect to the patient's soft tissue characteristics, by applying an appropriate soft tissue normalization factor;
• (6) comparing the normalized velocity to a statistical representation of normalized velocities for different groups of the population, grouped according to their age and bone condition;
• and
• (7) responsive to such comparison, generating a probabilistic evaluation of the bone condition of the patient.

A method of measuring, in-vivo, physical properties of a bone surrounded by soft tissue comprising:

• (1) transmitting from a transmitting site, into said soft tissue and bone, a first ultrasonic signal and a second ultrasonic signal;
• (2) receiving at a receiving site, first and second received signals produced, respectively, by the propagation of the first and second ultrasonic signals through the bone and surrounding soft tissue.
• (3) producing from said first received signal information characterizing the soft tissue surrounding the bone;
• and
• (4) producing from a combination of said first and second received signals a signal characterizing the bone.