Ultrasonic bone assessment apparatus and method

• US 20050197576A1
• Filed: 02/22/2005
• Published: 09/08/2005
• Est. Priority Date: 02/23/2004
• Status: Active Grant

• Current Assignee: CyberLogic, Inc.
• Original Assignee: CyberLogic, Inc.
• Inventors: Johnson, William A., Altman, Ronald L., Siffert, Robert S., Kaufman, Jonathan J., Luo, Gangming
• Granted Patent: US 8,202,219 B2
• Time in Patent Office: Days
• US Class Current: 600/438
• CPC Class Codes: A61B 8/0875 for diagnosis of bone A61B5/4504 takes precedence

Abstract

A method for the assessment of various properties of bone is provided. The method includes applying a pair of ultrasound transducers to skin on opposite sides of the bone and generating an ultrasound signal and directing the signal through both the bone to obtain a bone output signal. The method further includes establishing a set of parameters associated with the bone output signal and then further processing the parameters in order to obtain the desired bone property. Two novel parameters are also disclosed, namely the net time delay (NTD) and mean time duration (MTD) parameters. An apparatus for the assessment of various properties of bone is also provided. The apparatus includes a pair of ultrasound transducers which may be single-element transducers or array transducers in any combination. The apparatus further includes various computer hardware components and computer software for generating and directing the ultrasound signal, establishing the parameter set and performing the processing. In addition, an apparatus that is battery powered, handheld, and portable and operates in real time is also provided.

Claims

1. A method of non-invasive and quantitative assessment of the status of bone tissue in a bony member in vivo for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising the steps of:

acoustically coupling a first transducer and a second transducer to nearby skin on opposite sides of said bony member;

measuring a distance between said first transducer and said second transducer;

generating an ultrasound signal and directing said ultrasound signal from said first transducer to said second transducer through said bone tissue to obtain a bone-oriented output signal;

processing said bone-oriented output signal and said distance, whereby an estimate of at least one of a net time delay parameter and a mean time duration parameter is obtained; and

further processing said at least one of said net time delay parameter and said mean time duration parameter, whereby an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality is obtained.

2. The method of claim 1 wherein said processing step includes use of a method of moments.

3. The method of claim 1 wherein said bony member is a heel.

4. The method of claim 3 wherein at least one of said first transducer and said second transducer is an array transducer.

5. The method of claim 1 wherein said bony member is a wrist and wherein at least one of said first transducer and said second transducer is an array transducer.

6. The method of claim 1 wherein said bony member is a finger.

7. The method of claim 6 wherein at least one of said first transducer and said second transducer is an array transducer.

8. An apparatus for non-invasive and quantitative assessment of the status of bone tissue in a bony member in vivo for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising:

first and second transducers including means for acoustically coupling said first and second transducers to nearby skin on opposite sides of said bony member;

means for generating an ultrasound signal and directing said ultrasound signal from said first transducer to said second transducer through said bone tissue to obtain a bone-oriented output signal;

means for measuring a distance between set first transducer and said second transducer;

means for processing said bone-oriented output signal and said distance, whereby an estimate of at least one of a net time delay parameter and a mean time duration parameter is obtained; and

means for further processing said at least one of said net time delay parameter and said mean time duration parameter, whereby an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality is obtained.

9. The apparatus of claim 8 wherein said processing means includes use of a method of moments.

10. The apparatus of claim 8 wherein said bony member is a heel.

11. The apparatus of claim 8 wherein at least one of said first transducer and said second transducer is an array transducer.

12. The apparatus of claim 8 wherein said bony member is a wrist and wherein at least one of said first transducer and said second transducer is an array transducer.

13. The apparatus of claim 8 wherein said bony member is a finger.

14. The apparatus of claim 13 wherein at least one of said first transducer and said second transducer is an array transducer.

15. A method of non-invasive and quantitative assessment of the status of a radius bone in an arm in vivo for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising the steps of:

(a) acoustically coupling a first transducer and a second transducer to nearby skin on opposite sides of said arm wherein said second transducer has a plurality of elements;

(b) generating an ultrasound signal and directing said ultrasound signal from said first transducer to said second transducer through said arm to obtain a plurality of bone-oriented output signals;

(c) processing said plurality of bone-oriented output signals to obtain a plurality of ultrasound parameters; and

(d) further processing said plurality of ultrasound parameters, whereby an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality is obtained.

16. The method of claim 15 wherein said step (d) is replaced by a new step, said new step comprising a translating of said second transducer a prescribed distance along said arm and repeating said step (b) and said step (c) at least one time, whereby to obtain an image of said radius, and further processing said image to obtain an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture, and bone quality.

17. The method of claim 16, wherein said image includes soft tissue adjacent to said radius.

18. The method of claim 16, wherein said further processing includes determining a region of interest within said radius.

19. The method of claim 15 wherein said step (d) is replaced by a new step, said new step comprising a translating of said first transducer and said second transducer a prescribed distance along said arm and repeating said step (b) and said step (c) at least one time, whereby to obtain an image of said radius, and further processing said image to obtain an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture, and bone quality.

20. The method of claim 19, wherein said image includes soft tissue adjacent to said radius.

21. The method of claim 19, wherein said further processing includes determining a region of interest within said radius.

22. The method of claim 15, wherein said plurality of ultrasound parameters is at least one of a plurality of net time delay parameters, a plurality of acoustic transfer functions, a plurality of mean time duration parameters, a plurality of attenuation parameters, a plurality of velocity parameters, and a plurality of mean frequency parameters.

23. The method of claim 15, wherein said generating step includes a further step of measuring a distance between said first transducer and said second transducer, and wherein said plurality of ultrasound parameters is at least one of a plurality of net time delay parameters, a plurality of acoustic transfer functions, a plurality of mean time duration parameters, a plurality of attenuation parameters, a plurality of velocity parameters, and a plurality of mean frequency parameters.

24. The method of claim 15, wherein at least one of said first transducer and said second transducer is an array transducer, and wherein said plurality of ultrasound parameters comprises an image of said radius.

25. An apparatus for non-invasive and quantitative assessment of the status of a radius bone in an arm in vivo for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising:

first and second transducers including means for acoustically coupling said first and second transducers to nearby skin on opposite sides of said arm;

means for generating an ultrasound signal and directing said ultrasound signal from said first transducer to said second transducer through said arm to obtain a plurality of bone-oriented output signals;

means for processing said plurality of bone-oriented output signals to obtain a plurality of ultrasound parameters; and

means for further processing said plurality of said ultrasound parameters, whereby an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture, and bone quality is obtained.

26. The apparatus of claim 25, wherein said plurality of ultrasound parameters is at least one of a plurality of net time delay parameters, a plurality of mean time duration parameters, a plurality of attenuation parameters, and a plurality of mean frequency parameters.

27. The apparatus of claim 25, wherein said generating means includes a further means for measuring a distance between said first transducer and said second transducer.

28. The apparatus of claim 25, wherein at least one of said first and second transducers is an array transducer.

29. A method of non-invasive and quantitative assessment of the status of bone tissue in a bony member in a living being for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising the steps of:

acoustically coupling a first transducer and a second transducer to nearby skin on opposite sides of said bone tissue;

generating an ultrasound signal and directing said ultrasound signal from said first transducer to said second transducer through said bone tissue to obtain a bone-oriented output signal;

measuring a degree of bone turnover associated with said living being; and

processing said bone-oriented output signal and said degree of bone turnover, whereby an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality is obtained.

30. An apparatus for non-invasive and quantitative assessment of the status of bone tissue in a bony member in a living being for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising:

a first transducer and a second transducer including means for acoustic coupling said first and second transducers to nearby skin on opposite sides of said bone tissue;

means for generating an ultrasound signal and directing said ultrasound signal from said first transducer to said second transducer through said bony member to obtain a bone-oriented output signal;

means for measuring a degree of bone turnover associated with said living being; and

means for processing said bone-oriented output signal and said degree of bone turnover, whereby an estimate of said at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality is obtained.

31. A method of non-invasive and quantitative assessment of the status of bone tissue in a living being for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising the steps of:

acoustically coupling an ultrasound transducer to nearby skin overlying said bone tissue;

generating an ultrasound signal from said transducer through skin towards said bone tissue;

measuring a reflected ultrasound signal;

processing said reflected ultrasound signal whereby at least one of an acoustic impedance and a time delay associated with said bone tissue are obtained to thereby estimate at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality.

32. An apparatus for non-invasive and quantitative assessment of the status of bone tissue in a living being for at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture and bone quality comprising:

an ultrasound transducer including means for coupling said ultrasound transducer to nearby skin overlying said bone tissue;

means for generating an ultrasound signal from said transducer through said skin towards said bone tissue;

means for measuring a reflected ultrasound signal;

means for processing said reflected ultrasound signal, whereby at least one of an acoustic impedance and a time delay associated with said bone tissue is obtained, to thereby estimate at least one of the quantities, bone-mineral density, bone strength, bone fracture risk, bone architecture, and bone quality.