Method for periprosthetic bone mineral density measurement

Claim 1

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) establishing a measurement boundary which conforms to said implant boundary and is translated from said implant boundary by a predetermined distance along a translation axis; e) calculating bone mineral density within a plurality of segments contained between the implant boundary and the measurement boundary and displaced along the implant boundary to produce a set of segment values indicative of the density of the bone adjacent to said implant; and f) displaying on said visual display a plot of segment values versus distance along the implant boundary.

Claim 2

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) establishing a measurement boundary which conforms to said implant boundary and is translated from said implant boundary by a predetermined distance along a translation axis; e) calculating bone mineral density within a plurality of segments contained between the implant boundary and the measurement boundary and displaced along the implant boundary to produce a set of segment values indicative of the density of the bone adjacent to said implant; and f) displaying on said visual display a plot of segment values versus distance along the implant boundary.

Claim 6

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of the patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary d) identifying the position of a fiducial point of the bone within the matrix of data elements; e) calculating bone mineral density along a measurement axis having a predetermined distance and orientation with respect to said fiducial point and including a portion of the bone adjacent said implant as defined by the implant boundary; and f) displaying on said visual display a plot of the bone mineral density along said measurement axis.

Claim 7

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of the patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary d) identifying the position of a fiducial point of the bone within the matrix of data elements; e) calculating bone mineral density along a measurement axis having a predetermined distance and orientation with respect to said fiducial point and including a portion of the bone adjacent said implant as defined by the implant boundary; and f) displaying on said visual display a plot of the bone mineral density along said measurement axis.

Claim 8

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) establishing a measurement boundary which conforms to said implant boundary and is translated from said implant boundary by a predetermined distance along a translation axis; e) calculating bone mineral density for the data values located between the implant boundary and the measurement boundary and displaced along the implant boundary to produce a set of segment values corresponding to the density of the bone adjacent to the implant; f) averaging the segment values to obtain a value representing average bone mineral density adjacent the implant; and g) displaying on said visual display a visual representation of the result of step f).

Claim 9

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) establishing a measurement boundary which conforms to said implant boundary and is translated from said implant boundary by a predetermined distance along a translation axis; e) calculating bone mineral density for the data values located between the implant boundary and the measurement boundary and displaced along the implant boundary to produce a set of segment values corresponding to the density of the bone adjacent to the implant; f) averaging the segment values to obtain a value representing average bone mineral density adjacent the implant; and g) displaying on said visual display a visual representation of the result of step f).

Claim 10

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) employing the implant boundary to isolate and remove from the determination of bone mineral density data elements resulting from energy absorbed by said implant; e) employing the implant boundary to identify those data elements which result from energy absorbed by bone immediately adjacent said implant; f) displaying on said visual display a visual representation of said matrix showing said implant and said bone adjacent said implant; g) analyzing the data elements identified in step e) to determine bone mineral density of said bone adjacent said implant; and h) displaying the result of step g) on said visual display.

Claim 11

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, the method comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) employing the implant boundary to isolate and remove from the determination of bone mineral density data elements resulting from energy absorbed by said implant; e) employing the implant boundary to identify those data elements which result from energy absorbed by bone immediately adjacent said implant; f) displaying on said visual display a visual representation of said matrix showing said implant and said bone adjacent said implant; g) analyzing the data elements identified in step e) to determine bone mineral density of said bone adjacent said implant; and h) displaying the result of step g) on said visual display.

Claim 13

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) locating at least one region of interest, said region of interest containing only bone data elements and having one side adjacent said implant boundary, said one side conforming to the shape of said adjacent implant boundary; e) displaying on said visual display a visual representation of said bone, said implant and said region of interest; f) analyzing said bone data elements within said region of interest to calculate bone mineral density within said region of interest; and g) displaying on said visual representation of said calculated bone mineral density corresponding to the bone mineral density of bone adjacent said implant in said region of interest.

Claim 14

A method of using a dual energy densitometer having a visual display to determine bone mineral density in a patient having a bone with a prosthetic implant, comprising the steps of: a) scanning with said dual energy densitometer said patient in the region of said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form an implant boundary; d) locating at least one region of interest, said region of interest containing only bone data elements and having one side adjacent said implant boundary, said one side conforming to the shape of said adjacent implant boundary; e) displaying on said visual display a visual representation of said bone, said implant and said region of interest; f) analyzing said bone data elements within said region of interest to calculate bone mineral density within said region of interest; and g) displaying on said visual representation of said calculated bone mineral density corresponding to the bone mineral density of bone adjacent said implant in said region of interest.

Claim 16

A method of using a dual energy densitometer having a visual display to monitor change in bone density in bone adjacent a prosthetic implant, said method comprising the steps of: a) scanning with said dual energy densitometer said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form a first and second implant boundary generally opposed about an axis of the implant; d) employing the first and second implant boundaries to isolate data elements associated with the implant from said other data elements so that said implant data elements are removed from the determination of bone mineral density; e) analyzing said other data elements to identify bone data elements which result from energy absorbed by said bone; f) defining a medial and lateral edge boundary between said bone data elements and non-bone data elements of said other data elements; g) establishing at least one landmark on said edge boundary; h) using said landmark to locate at least two regions of interest, one region of interest on the medial side of said implant and the other region of interest on the lateral side of said implant, each said region of interest containing only bone data elements and each said region of interest having one side adjacent said implant boundary, each said one side conforming to the shape of one implant boundary; i) analyzing said bone data elements within each said region of interest to calculate bone mineral density within each said region of interest; j) displaying on said visual display a comparison of said calculated bone mineral density for each said region of interest corresponding to the bone mineral density of bone adjacent said implant in each said region of interest; and k) repeating on a subsequent date steps a) through j) so as to determine the change in bone mineral density in each said region of interest with time.

Claim 17

A method of using a dual energy densitometer having a visual display to monitor change in bone density in bone adjacent a prosthetic implant, said method comprising the steps of: a) scanning with said dual energy densitometer said bone and said implant so as to generate a two dimensional matrix of data elements wherein the value of each said data element of said matrix is proportional to the absorption of energy by said bone and implant at a defined location in the internal structure of said patient in said region, the matrix holding a corresponding location and data value for each data element; b) analyzing the matrix of data elements to identify a data element as a boundary data element, the boundary data element being on an edge of said implant adjacent to a portion of the bone of the patient, the location of said boundary data element being a function of a value and location of the boundary data element and a value and location of at least one immediately adjacent data element; c) using a plurality of the boundary data elements to form a first and second implant boundary generally opposed about an axis of the implant; d) employing the first and second implant boundaries to isolate data elements associated with the implant from said other data elements so that said implant data elements are removed from the determination of bone mineral density; e) analyzing said other data elements to identify bone data elements which result from energy absorbed by said bone; f) defining a medial and lateral edge boundary between said bone data elements and non-bone data elements of said other data elements; g) establishing at least one landmark on said edge boundary; h) using said landmark to locate at least two regions of interest, one region of interest on the medial side of said implant and the other region of interest on the lateral side of said implant, each said region of interest containing only bone data elements and each said region of interest having one side adjacent said implant boundary, each said one side conforming to the shape of one implant boundary; i) analyzing said bone data elements within each said region of interest to calculate bone mineral density within each said region of interest; j) displaying on said visual display a comparison of said calculated bone mineral density for each said region of interest corresponding to the bone mineral density of bone adjacent said implant in each said region of interest; and k) repeating on a subsequent date steps a) through j) so as to determine the change in bone mineral density in each said region of interest with time.