Local topological analysis at the distal radius by HR-pQCT: Application to in vivo bone microarchitecture and fracture assessment in the OFELY study.
High-resolution peripheral quantitative computed tomography (HR-pQCT) is an in-vivo technique used to analyze the distal radius and tibia. It provides a voxel size of 82μm. In addition to providing the usual microarchitecture parameters, local topological analysis (LTA) depicting rod- and plate-like trabeculae may improve prediction of bone fragility. Thirty-three women with prevalent wrist fractures from the OFELY cohort were compared with age-matched controls. Bone microarchitecture, including the structural model index (SMI), was assessed by HR-pQCT, and micro-finite element analysis (μFE) was computed on trabecular bone images of the distal radius (XtremeCT, Scanco Medical AG). A new LTA method was applied to label each bone voxel as a rod, plate or node. Then the bone volume fraction (BV/TV*), the rod, plate and node ratios over bone volume (RV/BV*, PV/BV*, NV/BV*) or total volume (RV/TV*, PV/TV*, NV/TV*) and the rod to plate ratio (RV/PV*) were calculated. Associations between LTA parameters and wrist fractures were computed in a conditional logistic regression model. Multivariate models were tested to predict the μFE-derived trabecular bone stiffness. RV/TV* (OR=4.41 [1.05-18.62]) and BV/TV* (OR=6.45 [1.06-39.3]), were significantly associated with prevalent wrist fracture, after adjustment for ultra distal radius aBMD. Multivariate linear models including PV/TV* or BV/TV*+RV/PV* predicted trabecular stiffness with the same magnitude as those including SMI. Conversion from plates into rods was significantly associated with bone fragility, with a negative correlation between RV/PV* and trabecular bone stiffness (r=-0.63, p<0.0001). We conclude that our local topological analysis is feasible for a voxel size of 82μm. After further validation, it may improve bone fragility description.
INSERM U1033, France. jeanbapia@gmail.com
J B
JB
Pialat
N
N
Vilayphiou
S
S
Boutroy
P J
PJ
Gouttenoire
E
E
Sornay-Rendu
R
R
Chapurlat
F
F
Peyrin
D000368:Aged; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D015999:Multivariate Analysis; D011884:Radius / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D011885:Radius Fractures / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods*