System and method for generating enhanced density distribution in a three dimensional model of a structure for use in skeletal assessment using a limited number of two-dimensional views

1. A method of generating a density enhanced model of an object includes the steps of:

generating a customized model of an object using a generic model of the object, the customized model comprising a plurality of volume elements, each volume element including density information;

generating a density map using a synthesized projection image of the customized model and a projection image of the object;

back-projecting gains from the density map into the customized model to modify the density information of each of the plurality of volume elements to provide a density enhanced customized model of the object and thereby transform the generic model of the object into an object specific model; and

performing at least one of storing the density enhanced customized model of the object and displaying the density enhanced customized model of the object on a user display.

2. The method according to claim 1 , wherein the object is a bone, the density information is associated with a density of the bone, and wherein the method includes the step of determining a bone mass density (BMD) of the object using the density enhanced customized model of the object.

3. The method according to claim 1 wherein the object is of a type, and wherein the step of generating a customized model of the object includes the step of:

selecting a standard model of a structure of the same type as the object, from a set of pre-defined three-dimensional models of structures, each standard model of each structure characterized by a plurality of modes of deformation;

generating a synthesized image of the structure using the standard model, the synthesized image having an associated projection angle;

comparing a projection image of the object, taken at the associated projection angle, to the synthesized image to obtain a measurement of differences between the synthesized image and the projection image; and

modifying the standard model of the structure to generate a customized model of the object by selectively varying at least one mode of deformation of the standard model and repeating the steps of generating, comparing and modifying until the measurement of differences is within a desired threshold.

4. The method of claim 1 , wherein the density map comprises an M×N array of density value entries, and wherein the step of generating a two-dimensional density map includes the steps of:

generating a synthesized projection image of the customized model at a projection angle associated with the projection image of the object, the projection image and the synthesized projection image each comprising an M×N array of pixels; and

for each entry in the density map, storing a value associated with a relationship between a projection image pixel and a synthesized projection image pixel at similar locations in the respective synthesized projection image and projection image.

5. The method of claim 4 wherein the mathematical relationship is:

G (M,N) =DXA — PI (M,N) /DRR (M,N)

wherein DXA_PI(M,N) is a first pixel intensity value of the projection image at location (M,N), and DRR(M,N) is a second pixel intensity value of the synthesized projection image at location (M,N).

6. A system for assessing characteristics of an object includes:

a processor;

a storage medium for storing a projection image of an object;

program code stored in the storage medium and operable when executed upon by the processor to:

generate a customized model of the object using a generic model of the object and the projection image of the object, the customized model comprising a plurality of volume elements, each volume element including density information;

generate a density map using a synthesized projection image of the customized model and a projection image of the object; and

back-project gains from the density map into the customized model to modify the density information of each of the plurality of volume elements to provide a density enhanced customized model of the object and thereby transform the generic model of the object into an object specific model; and wherein the density enhanced customized model of the object is stored in the storage medium.

7. The system of claim 6 wherein the density map comprises an M×N array of density values and wherein the program code that is operable to generate a density map includes program code operable to:

generate a synthesized projection image of the customized model at a projection angle associated with the projection image of the object, the projection image and the synthesized projection image each comprising an M×N array of pixels; and

for each (M,N) entry in the density map, store a value associated with a relationship between a first image pixel at an (M,N) location of the projection image and a second image pixel at an (M,N) location of the synthesized projection image pixel.

8. The system of claim 7 wherein the relationship is defined by the below equation:

G (M,N) =DXA — PI (M,N) /DRR (M,N)

wherein DXA_PI(M,N) is a pixel intensity value of the projection image at location (M,N) and DRR(M,N) is the pixel intensity value of the synthesized projection image at location (M,N).