Stress–strain index: Difference between revisions
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The '''[[Stress (physics)|stress]]–[[Strain (materials science)|strain index]]''' (SSI), of a [[bone]], is a surrogate measure of bone [[Strength of materials|strength]]<ref>{{cite journal |vauthors=Ward K, Roberts S, Adams J, Mughal M | title = Bone geometry and density in the skeleton of pre-pubertal gymnasts and school children. | journal = Bone | volume = 36 | issue = 6 | pages = 1012–8 | year = 2005 | pmid = 15876561 | doi = 10.1016/j.bone.2005.03.001}}</ref> determined from a cross-sectional scan by QCT or [[pQCT]] ([[radiology|radiological scan]]). The stress–strain index is used to compare the structural parameters determined by analysis of QCT/pQCT cross-sectional scans to the results of [[three-point flexural test|three-point bending test]]. |
The '''[[Stress (physics)|stress]]–[[Strain (materials science)|strain index]]''' (SSI), of a [[bone]], is a surrogate measure of bone [[Strength of materials|strength]]<ref>{{cite journal |vauthors=Ward K, Roberts S, Adams J, Mughal M | title = Bone geometry and density in the skeleton of pre-pubertal gymnasts and school children. | journal = Bone | volume = 36 | issue = 6 | pages = 1012–8 | year = 2005 | pmid = 15876561 | doi = 10.1016/j.bone.2005.03.001}}</ref> determined from a cross-sectional scan by QCT or [[pQCT]] ([[radiology|radiological scan]]). The stress–strain index is used to compare the structural parameters determined by analysis of QCT/pQCT cross-sectional scans to the results of [[three-point flexural test|three-point bending test]]. |
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Revision as of 12:19, 29 March 2023
The stress–strain index (SSI), of a bone, is a surrogate measure of bone strength[1] determined from a cross-sectional scan by QCT or pQCT (radiological scan). The stress–strain index is used to compare the structural parameters determined by analysis of QCT/pQCT cross-sectional scans to the results of three-point bending test.
Definition
It is calculated using the following formula:[2]
Where:
- rmax is the distance of voxel from centre
- CD is the apparent cortical (bone) density
- ND is the normal (cortical bone) density
- ri is the pixel position from the centre
- a is the area of a pixel
History and relation to moments of inertia
It was developed by the manufacturer of a peripheral quantitative CT (pQCT) scanner,[2] and is considered to be by some an improvement over the information provided by calculating the area moments of inertia and polar moments of inertia.
References
- ^ Ward K, Roberts S, Adams J, Mughal M (2005). "Bone geometry and density in the skeleton of pre-pubertal gymnasts and school children". Bone. 36 (6): 1012–8. doi:10.1016/j.bone.2005.03.001. PMID 15876561.
- ^ a b Hasegawa Y, Schneider P, Reiners C (2001). "Age, sex, and grip strength determine architectural bone parameters assessed by peripheral quantitative computed tomography (pQCT) at the human radius". J Biomech. 34 (4): 497–503. doi:10.1016/S0021-9290(00)00211-6. PMID 11266673.