Noninvasive tissue assessment

• US 7,435,232 B2
• Filed: 09/07/2004
• Issued: 10/14/2008
• Est. Priority Date: 09/05/2003
• Status: Expired due to Fees

• Current Assignee: Rice University
• Original Assignee: Rice University
• Inventors: Liebschner, Michael
• Primary Examiner(s): Hindenburg; Max
• Assistant Examiner(s): HOEKSTRA, JEFFREY GERBEN
• Application Number:
  US10/935,432
• Publication Number:
  US 20050113691A1
• Time in Patent Office: 1,498 Days
• Field of Search: 600/552, 600/300, 600/301, 600/587, 600/586, 600/372, 600/382, 600/384, 600/386, 128/920, 128/923, 601/46, 601/80, 606/201, 606/202
• US Class Current: 600/587
• CPC Class Codes: A61B 5/0051 by applying vibrations
• CPC Class Codes: A61B 5/4504 Bones A61B5/4547 takes precedence
• CPC Class Codes: A61B 5/4509 Bone density determination
• CPC Class Codes: A61B 5/4514 Cartilage
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: A61B 5/4523 Tendons
• CPC Class Codes: A61B 5/4533 Ligaments
• CPC Class Codes: A61B 9/00 Instruments for examination by percussion; Pleximeters
• CPC Class Codes: Y10S 128/92 Computer assisted medical diagnostics
• CPC Class Codes: Y10S 128/923 by comparison of patient data to other data

Abstract

Methods and apparatus for non-invasively assessing physiological hard of soft tissue of human and other species are described. In a preferred embodiment, tissue is vibrationally stimulated in vivo through a frequency spectrum. The tissue reacts against the stimulus and the reaction is preferably measured and recorded. Based on analytical algorithms or comparisons with previously taken measurements, changes within the tissue can be detected and used for diagnostic purposes. Further embodiments describe the usage of the device and methods for in vivo intra-operative and post-operative implant evaluations and as a therapeutic tool.

Claims

1. A method for tissue quality assessment comprising:

(a) engaging a tissue with a handheld device at a contact point and with a contact load, wherein the handheld device comprises a vibration generator for inducing mechanical vibrations over a range of frequencies at the contact point and one or more sensors for measuring the applied force of the mechanical vibrations and for measuring the tissue response at the same contact point;

(b) initiating a frequency sweep at the same contact point in (a) with the handheld device;

(c) simultaneously performing the frequency sweep over the range of frequencies based on a given set of operational parameters while maintaining the contact load to induce mechanical vibrations in the tissue at the same contact point in (a) and

measuring the applied force of the mechanical vibrations and the tissue response at the same contact point in (a) with the handheld device to assess tissue quality.

2. The method according to claim 1 wherein the frequency range is between 20 Hz and 1.5 MHz.

3. The method according to claim 2 wherein the frequency range is between 20 Hz and 600 kHz.

4. The method according to claim 2 wherein the frequency range is between 800 Hz and 1.5 MHz.

5. The method according to claim 1 further comprising selecting the operational parameters prior to engaging the tissue with the handheld device.

6. The method according to claim 5 wherein the operational parameters comprise one or more inputs selected from the group consisting of anatomic site, age, sex, body weight and shoe size.

7. The method according to claim 1 wherein providing a user response comprises calculating a relative value based on comparative data from a database.

8. The method according to claim 7 wherein the user response comprises a diagnostic value for osteoporosis.

9. The method according to claim 1 wherein providing a user response comprises calculating a relative value based on an analytical method.

10. The method according to claim 1 wherein the user response comprises a diagnostic value for bone fractures.

11. The method according to claim 1 wherein the vibration generator comprises a shaker.

12. The method according to claim 11 wherein the shaker comprises a device selected from the group consisting of piezoelectric devices, electromechanical devices, hydraulic devices and pneumatic devices.

13. The method according to claim 11 wherein the shaker comprises an electromagnetic device.

14. The method according to claim 1 wherein one or more sensors comprises an impedance transducer.

15. The method according to claim 14 wherein the impedance transducer measures both input and output signals.

16. The method according to claim 14 wherein the impedance transducer comprises one or more selected from the group consisting of accelerometers, displacement transducers, load cells, and combinations thereof.

17. The method according to claim 1 wherein the device further comprises a means for determining the contact load.

18. The method according to claim 17 wherein the means for determining the contact load comprises a tissue contact pressure sensor.

19. The method according to claim 17 wherein the means for determining the contact load comprises a load cell.

20. The method according to claim 17 wherein the device further comprises a means for outputting that a desirable load has been achieved.

21. The method according to claim 20 wherein the means for outputting that a desirable load has been achieved comprises at least one LED.

22. The method of claim 1 wherein the contact load is between 10 N and 100 N.

23. The method according to claim 1 wherein the contact load is between 10 N and 20 N.

24. The method according to claim 1 further comprising repeating (a)-(c) at a different contact point.

25. The method according to claim 1 further comprising using a Fast Fourier transform to convert the force and tissue response measured in (c) into frequency domain data and using the frequency domain data to calculate mechanical transfer functions comprising accelerance, effective mass, mobility, impedance, compliance, or stiffness.

26. A method for testing an anatomical region, the method comprising:

(a) selecting operational parameters;

(b) engaging the anatomical region with a handheld device comprising an electromagnetic shaker, wherein a contact force is applied to the anatomical region by the handheld device yielding a contact pressure;

(c) simultaneously performing a frequency sweep over a range of frequencies based on a given set of operational parameters to generate mechanical vibrations within the same anatomical region while maintaining the contact pressure

and collecting tissue response data with the handheld device at the same anatomical region in (b), the tissue response data including at least force and acceleration data from the mechanical vibrations; and

(d) providing a response based on the tissue response data.

27. The method according to claim 26 wherein the force applied is from between 10 N and 100 N.

28. The method according to claim 26 wherein the contact pressure applies a force between 10 N and 20 N to the anatomical region.

29. The method according to claim 26 wherein the operational parameters are selected from the group consisting of anatomic site, age, sex, body weight, shoe size, and combinations thereof.

30. The method according to claim 29 wherein the operational information further comprises a file name.

31. The method according to claim 26 wherein the frequency sweep is between 20 Hz and 600 kHz.

32. The method according to claim 26 wherein the frequency sweep is between 800 Hz and 1.5 MHz.

33. The method according to claim 26 wherein providing a response based on the tissue response data comprises confirmation that the data collected was a valid sample.

34. The method according to claim 26 wherein providing a response based on the tissue response data comprises calculating one or more relative values based on comparative data from a database.

35. The method according to claim 26 wherein providing a response based on the tissue response data comprises

(i) confirming that the data collected was a valid sample;

(ii) calculating one or more raw values based on the data collected;

(iii) comparing the raw values from (ii) to either;

(1) one or more previous calculated raw values for a given patient from the same anatomic site or contralateral site, or

(2) a database of similar values;

(iv) determining a relative diagnosis based on the comparison in step (iii); and

(v) communicating the relative diagnosis to a user.

36. The method according to claim 35 wherein the relative diagnosis comprises one or more forms selected from the group consisting of alpha-numeric characters, electronic data, graphs, pictures, video, charts, icons, sounds, and combinations thereof.

37. The method according to claim 26 further comprising repeating (a)-(d) at a different anatomical region.

38. The method according to claim 26 further comprising using a Fast Fourier transform to convert the tissue response data measured in (c) into frequency domain data and using the frequency domain data to calculate mechanical transfer functions comprising accelerance, effective mass, mobility, impedance, compliance, or stiffness.