US 10,299,719 B2Granted

Systems and methods for establishing the stiffness of a bone using mechanical response tissue analysis

AssigneeOhio University

InventorsLyn Bowman, Patricia A. Arnold, Emily R. Ellerbrock

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Abstract

Parametric model based computer implemented methods for determining the stiffness of a bone, systems for estimating the stiffness of a bone in vivo, and methods for determining the stiffness of a bone. The computer implemented methods include determining a complex compliance frequency response function Y(f) and an associated complex stiffness frequency response function H(f) and fitting a parametric mathematical model to Y(f) and to H(f). The systems include a device for measuring the stiffness of the bone in vivo and a data analyzer to determine a complex compliance frequency response function Y(f) and an associated complex stiffness frequency response function H(f). The methods for determining the stiffness include fitting a parametric model to stiffness of the skin-bone complex as a function of frequency H(f) and the compliance of the skin-bone complex as a function of frequency Y(f).

Claims28

Dependent claims

A parametric model based computer implemented method for determining the stiffness of a bone, comprising:

(1) applying a superposition of static and oscillatory forces (F) with a mechanical force applicator over a range of frequencies (f) to a region of a skin-bone complex thereby exciting oscillatory accelerations (a) over the range of frequencies (f) of the skin-bone complex;
(2) receiving measurement data of the oscillatory forces (F as functions of time F(t) and obtaining the resulting oscillatory acceleration data (a) as functions of time a(t) with a data receiver communicatively coupled to a controller comprising a processor and a storage medium containing computer readable and executable instructions which, when executed by the processor, cause the controller to automatically:
(i) transform a(t) and F(t) to functions of frequency, a(f) and F(f),
(ii) reduce a(f) and F(f) to accelerance frequency response function data A(f),
(iii) determine, a complex compliance frequency response function, Y(f) and associated complex stiffness frequency response function H(f),
(iv) fit a parametric mathematical model to Y(f) to obtain a first set of parameters of the parametric mathematical model, including the stiffness of the bone (KB),
(v) fit the parametric mathematical model to H(f) to obtain a second set of parameters of the parametric mathematical model, including the stiffness of the bone (KB),
(vi) after fitting, determine discrepancies between each parameter of the first set of parameters and each corresponding parameter of the second set of parameters as a measure of conformity thereof to the parametric mathematical model, and
(vii) save the measure of conformity, the first set of parameters, and the second set of parameters as a parameter set for the measured region of the skin-bone complex;
(3) positioning the mechanical force applicator at a laterally shifted region of the skin-bone complex and repeating steps (1)-(2), such that the static and oscillatory forces (F) in step (1) are applied to the laterally shifted region of the skin-bone complex, thereby obtaining a parameter set for the laterally shifted region of the skin-bone complex;
(4) repeating step (3) until the measure of conformity worsens, and determining an optimized parameter set based on the measure of conformity;
and
(5) determining the stiffness of the bone from (kb) values of the optimized parameter set.

10 more elements

A method for determining the stiffness of a bone, comprising:

(1) applying a controlled superposition of static and oscillatory forces (F) measured as a first function of frequency F(f) over a range of frequencies to a skin-bone complex in vivo with a mechanical force applicator, thereby exciting oscillatory accelerations (a) over the range of frequencies of the skin-bone complex;
(2) measuring the resulting oscillatory accelerations (a) of the skin-bone complex as a second function of frequency a(f);
(3) transforming F(f) and a(f) to obtain the stiffness of the skin-bone complex as a function of frequency H(f);
(4) transforming F(f) and a(f) to obtain the compliance of the skin-bone complex as a function of frequency Y(f);
(5) fitting a parametric model to H(f) to obtain a first set of parameters of the parametric model, including the stiffness of the bone (KB);
(6) fitting the parametric model to Y(f) to obtain a second set of parameters of the parametric model, including the stiffness of the bone (KB);
(7) after fitting, determining discrepancies between each parameter of the first set of parameters and each corresponding parameter of the second set of parameters as a measure of conformity thereof to the parametric mathematical model;
(8) saving the measure of conformity, the first set of parameters, and the second set of parameters as a parameter set for the measured region of the skin-bone complex;
(9) positioning the mechanical force applicator at a laterally shifted region of the skin-bone complex and repeating steps (1)-(8), such that the static and oscillatory forces (F) in step (1) are applied to the laterally shifted region of the skin-bone complex, thereby obtaining a parameter set for the laterally shifted region of the skin-bone complex;
(10) repeating step (9) until the measure of conformity worsens, and determining an optimized parameter set based on the measure of conformity;
and
(11) determining the stiffness of the bone from (KB) values of the optimized parameter set.

9 more elements

A parametric model based computer implemented method for determining the stiffness of a bone, comprising:

(1) applying a superposition of static and oscillatory forces (F) with a mechanical force applicator over a range of frequencies (f) to a region of a skin-bone complex thereby exciting oscillatory accelerations (a) over the range of frequencies (f) of the skin-bone complex;
(2) receiving measurement data of the oscillatory forces (F as functions of time F(t) and obtaining the resulting oscillatory acceleration data (a) as functions of time a(t) with a data receiver communicatively coupled to a controller comprising a processor and a storage medium containing computer readable and executable instructions which, when executed by the processor, cause the controller to automatically:
(i) transform a(t) and F(t) to functions of frequency, a(f) and F(f),
(ii) reduce a(f) and F(f) to accelerance frequency response function data A(f),
(iii) determine, a complex compliance frequency response function, Y(f) and associated complex stiffness frequency response function H(f),
(iv) fit a parametric mathematical model to Y(f) to obtain a first set of parameters of the parametric mathematical model, including the stiffness of the bone (KB),
(v) fit the parametric mathematical model to H(f) to obtain a second set of parameters of the parametric mathematical model, including the stiffness of the bone (KB),
(vi) after fitting, determine discrepancies between each parameter of the first set of parameters and each corresponding parameter of the second set of parameters as a measure of conformity thereof to the parametric mathematical model, wherein the measure of conformity between the first set of parameters and the second set of parameters is quantified as a root mean square therebetween of the percentage differences between each of the parameters of the first set of parameters and the second set of parameters, and
(vii) save the measure of conformity, the first set of parameters, and the second set of parameters as a parameter set for the measured region of the skin-bone complex;
(3) positioning the mechanical force applicator at a laterally shifted region of the skin-bone complex and repeating steps (1)-(2), such that the static and oscillatory forces (F) in step (1) are applied to the laterally shifted region of the skin-bone complex, thereby obtaining a parameter set for the laterally shifted region of the skin-bone complex;
(4) repeating step (3) until the measure of conformity worsens, and determining a optimized parameter set based on the measure of conformity;
and
(5) determining the stiffness of the bone from (kb) values of the optimized parameter set.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/782,712Filed 11 Apr 2014 · us provisional application
Priority: 11 Apr 2013
Published: US 2016/0058365 A13 Mar 2016
Granted: 28 May 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

A61B 5/4509
Bones: bone density determination
A61B 5/0051
Detecting, measuring or recording by applying mechanical forces or stimuli: by applying vibrations
A61B 5/442
Skin evaluation, e.g. for skin disorder diagnosis: evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment
A61B 5/4504
For evaluating or diagnosing the musculoskeletal system or teeth: bones