- Email: [email protected]
15 3D Local Orientation Analysis of the Canal Network in Cortical Bone Synchrotron Micro-CT Images
Giuseppe and Toffanin
107
that morphometric analysis of ultrastructural phenotypes will deliver new insights in the assessment of bone quality.
variability was observed within each sample but the results are in agreement with previously published works. This is the first 3D evaluation of micro-cracks in trabecular bone. Table 1 Average parameters of all cracks in a sample of each group
15 3D LOCAL ORIENTATION ANALYSIS OF THE CANAL NETWORK IN CORTICAL BONE SYNCHROTRON MICRO-CT IMAGES 1,2
3
3
3
1,2 1
Z. Peter, V. Bousson, C. Bergot, Y. Wu, and F. Peyrin , CREATISLRMN, UMR CNRS 5220, Inserm U630, Lyon, France, 2ESRF, Grenoble, France, 3UMR CNRS 7052 Paris, France Human cortical bone is arranged as a compact structure, including a complex canal network: the longitudinally oriented Haversian canals, and transversely oriented Volkmann canals. New secondary osteons are formed through the creation of ‘‘breakout zones’’ in the lateral walls of existing channels in the bone. In a general sense, remodeling continually modifies the canal network through the creation of new canals that branch off of existing canals. Therefore, it is also important to understand the canal network in the context of the processes responsible for bone formation and turnover. Three-dimensional imaging of cortical bone samples using 3D synchrotron micro-CT allowed us to observe visually the qualitative differences in the microstructure of the cortical network porosity and to distinguish between Volkmann and Havers canals. In this work, we propose an automatic method for the local analysis of the orientation of the 3D complex canals network. First, a 3D skeleton of the canal network is computed, then the angles (q,4) of the principal direction in spherical coordinates are estimated at each line point of the skeleton. This method gives a more detailed analysis than the conventional MIL method, which provides a global orientation. In addition, it does not rely on any assumption about the structures conversely to stereology-based methods. First, we estimated the 2D distribution of the orientation angles and their relation to the canal diameter on 40 cortical bone samples. Second, we proposed a parametric procedure to separate the Volkmann and Havers canals based on this local information. However, due to the complexity of the actual canal network, setting the parameters is a critical issue since there is no clear definition of the Volkmann and Havers canals in 3D. In conclusion, this method is expected to provide new quantitative reference data on the 3D organization of the canal network and a better comprehension of its physio-pathological modifications with age or disease.
Sample in Group
BV/ TV (%)
N.Cr (#/mm3)
Cr.V (mm3x106) meanstd
Cr.Th (mm) meanstd
Cr.L (mm) meanstd
Cr.w (mm) meanstd
N.CrXLa (#/mm3)
N.Cr.Bdr (#/mm3)
N.Cr.XBdr (#/mm3)
1
22.79
0.66
0.07
0.07
0.40
0
3
22.61
0.53
10.04 12.12
3.2 1.1
87.7 62.1 38.1 41.8 58.6 43.3
0.53
0.80
163.5 89.2 92.9 122.5 114.7 78.2
0.47
17.36
19.70 25.98 9.52 25.89
3.2 1.1
2
0.33
0.07
0
3.5 1.5
17 EFFECT OF ESTROGEN METABOLISM ON BODY COMPOSITION N. Napoli,1 S. Vattikuti,2 T. Giri,1 M. Azadfard,1 and R. Armamento-Villareal1, 1 Bone and Mineral Diseases, Washington University in St Louis, St Louis, MO, USA, 2Internal Medicine, St Luke Hospital, Chesterfield, MO, USA; Objective: Menopause is associated with changes in bone, muscle and fat mass. The importance of postmenopausal estrogen metabolism in bone health has been established. However, its role in the maintenance of body composition remains undetermined. The objective of this study is to investigate the effect of estrogen metabolism on body composition in postmenopausal women. Study design: This is a cross sectional study of 73 post menopausal Caucasian women, 45-80 y.o. Urinary estrogen metabolites were measured by ELISA, serum estradiol and sex hormone binding globulin by ultrasensitive RIA. The whole and regional body composition was measured by DXA. Results: The ratio of nonestrogenic to estrogenic metabolites (2OHE1 /16aOHE1), was inversely correlated with appendicular lean index (aLMI), total lean mass index (LMI), total fat mass index (FMI) and body mass index (BMI). The total metabolites (2OHE1 + 2MeOE1 + 16aOHE1 + E3) were also inversely correlated with aLMI, FMI, % truncal fat and BMI while free estradiol index (FEI) was positively correlated with all the parameters (aLMI, LMI, FMI, % truncal fat) and BMI. Comparing the fat and lean parameters according to tertiles of 2OHE1 /16aOHE1 ratio showed that subjects in the lowest tertile had the highest aLMI, LMI, FMI and % truncal fat relative to the upper two tertiles whose mean values were comparable; Body composition divided according to tertiles of 2OHE1 /16aOHE1 ratio
16 THREE-DIMENSIONAL EVALUATION OF MICROCRACKS IN HUMAN TRABECULAR BONE A. Larrue,1,2 Z. Peter,2 A. Rattner,3 L. Vico,3 and F. Peyrin1,2, 1INSERM U630, UMR CNRS 5220, CREATIS-LRMN , INSA-Lyon, Villeurbanne, France, 2ESRF, Grenoble, France, 3INSERM U890, LBTO, Universite´ de Saint-Etienne, SaintEtienne, France While the understanding of micro-damages in bone tissue is raising increasing interest there are little data on micro-cracks in trabecular bone. In this work, we used 3D Synchrotron radiation micro-CT (SRmCT) at the micrometer scale to characterize micro-cracks in human trabecular bone. Cylindrical samples (diameter 10 mm) were extracted from human femoral heads taken out during arthroplasty. While they were maintained in a physiological environment to preserve soft tissues, different cyclic fatigues (strain: w0.1%) were applied to 2 groups of samples ((1): 10 Hz, 10 000 cycles; (2): 1 Hz, 7200 cycles). A control group (3) was also studied. After that, 5 mm 5 mm 10 mm parallelepipeds were cut and embedded in PMMA resin. For each sample, two regions of interest of (2.8 mm 2.8 mm 2.2 m) were imaged with the SRmCT system developed on beamline ID19 at the ESRF (Grenoble, France). The voxel size was 1.4mm and the energy was 24 keV. Micro-cracks corresponding to the different types described in the literature (linear, parallel, cross-hatched) could be observed in the tomographic slices, showing that the spatial resolution was adapted. Moreover, we enumerated the number of cracks N.Cr per tissue volume, the number of cracks intercepting a lacuna (N.CrXLa), following (N.Cr Bdr) or stopped (N.CrXBdr) by the boundary between two areas of different mineralization. We developed a semi-automatic process, robust to noise, low contrast and ring artefacts, to segment micro-cracks in 3D images. Since they are described as thin planar ellipses, we computed the best-fitting ellipsoids to access the cracks length (Cr.L) and width (Cr.w). We also estimated their thickness (Cr.Th) and volume (Cr.V). We present the average of the measures of all cracks in one sample of each group in Table 1. A large
Journal of Clinical Densitometry: Assessment of Skeletal Health
Body composition parameters LMI (total lean) (gr/m2) aLMI (gr/m2) FMI (Total fat) (gr/m2) % Truncal Fat
Tertile 1(!1.2) 17559 7384 12268 38
Tertile 2 (1.2e2.2)
Tertile 3 (O2.2)
383 15949 374 15997 382 187 6641 182 6683 186 648 9784 636 9374 646 1.5 33 1.5 33 1.5
P value 0.005 0.009 0.004 0.04
P value adjusted for age.
In the multiple regression analysis 2OHE1 /16OHE1, FEI and age were found to be important predictors of aLMI; 2OHE1 /16OHE1, and FEI for LMI ; 2OHE1 /16OHE1, 16OHE1 and FEI, for FMI ; 2OHE1 and FEI for % truncal fat. Conclusion: The decrease in estrogen catabolism (i.e. low total metabolites) and predominance of active pathway (i.e. lower 2:16 ratio) in addition to higher FEI is associated with higher BMI, % truncal fat and lean mass. Our results suggest that an estrogenic milieu created by a shift to the active pathway of estrogen metabolism and a reduction in the rate of estrogen catabolism, although associated with higher lean mass, is also associated with increased abdominal adiposity.
18 PEAK BONE GEOMETRY: POSITIVE INFLUENCE OF INTENSE WEIGHT-BEARING PHYSICAL ACTIVITY ON FEMUR MACRO ARCHITECTURE IN YOUNG WOMEN BETWEEN 17 AND 29 YEARS S. Bre´ban C. Chappard and C.L. Benhamou, 1INSERM Unit 658, Orleans Regional Hospital, Orleans, France; Rationale: Weight-bearing physical activity induces higher BMD values and higher bone geometry parameters. Peripheral Tomography and Magnetic Resonance Imaging are the main tools used to assess bone geometry parameters in
Volume 12, 2009
107
that morphometric analysis of ultrastructural phenotypes will deliver new insights in the assessment of bone quality.
variability was observed within each sample but the results are in agreement with previously published works. This is the first 3D evaluation of micro-cracks in trabecular bone. Table 1 Average parameters of all cracks in a sample of each group
15 3D LOCAL ORIENTATION ANALYSIS OF THE CANAL NETWORK IN CORTICAL BONE SYNCHROTRON MICRO-CT IMAGES 1,2
3
3
3
1,2 1
Z. Peter, V. Bousson, C. Bergot, Y. Wu, and F. Peyrin , CREATISLRMN, UMR CNRS 5220, Inserm U630, Lyon, France, 2ESRF, Grenoble, France, 3UMR CNRS 7052 Paris, France Human cortical bone is arranged as a compact structure, including a complex canal network: the longitudinally oriented Haversian canals, and transversely oriented Volkmann canals. New secondary osteons are formed through the creation of ‘‘breakout zones’’ in the lateral walls of existing channels in the bone. In a general sense, remodeling continually modifies the canal network through the creation of new canals that branch off of existing canals. Therefore, it is also important to understand the canal network in the context of the processes responsible for bone formation and turnover. Three-dimensional imaging of cortical bone samples using 3D synchrotron micro-CT allowed us to observe visually the qualitative differences in the microstructure of the cortical network porosity and to distinguish between Volkmann and Havers canals. In this work, we propose an automatic method for the local analysis of the orientation of the 3D complex canals network. First, a 3D skeleton of the canal network is computed, then the angles (q,4) of the principal direction in spherical coordinates are estimated at each line point of the skeleton. This method gives a more detailed analysis than the conventional MIL method, which provides a global orientation. In addition, it does not rely on any assumption about the structures conversely to stereology-based methods. First, we estimated the 2D distribution of the orientation angles and their relation to the canal diameter on 40 cortical bone samples. Second, we proposed a parametric procedure to separate the Volkmann and Havers canals based on this local information. However, due to the complexity of the actual canal network, setting the parameters is a critical issue since there is no clear definition of the Volkmann and Havers canals in 3D. In conclusion, this method is expected to provide new quantitative reference data on the 3D organization of the canal network and a better comprehension of its physio-pathological modifications with age or disease.
Sample in Group
BV/ TV (%)
N.Cr (#/mm3)
Cr.V (mm3x106) meanstd
Cr.Th (mm) meanstd
Cr.L (mm) meanstd
Cr.w (mm) meanstd
N.CrXLa (#/mm3)
N.Cr.Bdr (#/mm3)
N.Cr.XBdr (#/mm3)
1
22.79
0.66
0.07
0.07
0.40
0
3
22.61
0.53
10.04 12.12
3.2 1.1
87.7 62.1 38.1 41.8 58.6 43.3
0.53
0.80
163.5 89.2 92.9 122.5 114.7 78.2
0.47
17.36
19.70 25.98 9.52 25.89
3.2 1.1
2
0.33
0.07
0
3.5 1.5
17 EFFECT OF ESTROGEN METABOLISM ON BODY COMPOSITION N. Napoli,1 S. Vattikuti,2 T. Giri,1 M. Azadfard,1 and R. Armamento-Villareal1, 1 Bone and Mineral Diseases, Washington University in St Louis, St Louis, MO, USA, 2Internal Medicine, St Luke Hospital, Chesterfield, MO, USA; Objective: Menopause is associated with changes in bone, muscle and fat mass. The importance of postmenopausal estrogen metabolism in bone health has been established. However, its role in the maintenance of body composition remains undetermined. The objective of this study is to investigate the effect of estrogen metabolism on body composition in postmenopausal women. Study design: This is a cross sectional study of 73 post menopausal Caucasian women, 45-80 y.o. Urinary estrogen metabolites were measured by ELISA, serum estradiol and sex hormone binding globulin by ultrasensitive RIA. The whole and regional body composition was measured by DXA. Results: The ratio of nonestrogenic to estrogenic metabolites (2OHE1 /16aOHE1), was inversely correlated with appendicular lean index (aLMI), total lean mass index (LMI), total fat mass index (FMI) and body mass index (BMI). The total metabolites (2OHE1 + 2MeOE1 + 16aOHE1 + E3) were also inversely correlated with aLMI, FMI, % truncal fat and BMI while free estradiol index (FEI) was positively correlated with all the parameters (aLMI, LMI, FMI, % truncal fat) and BMI. Comparing the fat and lean parameters according to tertiles of 2OHE1 /16aOHE1 ratio showed that subjects in the lowest tertile had the highest aLMI, LMI, FMI and % truncal fat relative to the upper two tertiles whose mean values were comparable; Body composition divided according to tertiles of 2OHE1 /16aOHE1 ratio
16 THREE-DIMENSIONAL EVALUATION OF MICROCRACKS IN HUMAN TRABECULAR BONE A. Larrue,1,2 Z. Peter,2 A. Rattner,3 L. Vico,3 and F. Peyrin1,2, 1INSERM U630, UMR CNRS 5220, CREATIS-LRMN , INSA-Lyon, Villeurbanne, France, 2ESRF, Grenoble, France, 3INSERM U890, LBTO, Universite´ de Saint-Etienne, SaintEtienne, France While the understanding of micro-damages in bone tissue is raising increasing interest there are little data on micro-cracks in trabecular bone. In this work, we used 3D Synchrotron radiation micro-CT (SRmCT) at the micrometer scale to characterize micro-cracks in human trabecular bone. Cylindrical samples (diameter 10 mm) were extracted from human femoral heads taken out during arthroplasty. While they were maintained in a physiological environment to preserve soft tissues, different cyclic fatigues (strain: w0.1%) were applied to 2 groups of samples ((1): 10 Hz, 10 000 cycles; (2): 1 Hz, 7200 cycles). A control group (3) was also studied. After that, 5 mm 5 mm 10 mm parallelepipeds were cut and embedded in PMMA resin. For each sample, two regions of interest of (2.8 mm 2.8 mm 2.2 m) were imaged with the SRmCT system developed on beamline ID19 at the ESRF (Grenoble, France). The voxel size was 1.4mm and the energy was 24 keV. Micro-cracks corresponding to the different types described in the literature (linear, parallel, cross-hatched) could be observed in the tomographic slices, showing that the spatial resolution was adapted. Moreover, we enumerated the number of cracks N.Cr per tissue volume, the number of cracks intercepting a lacuna (N.CrXLa), following (N.Cr Bdr) or stopped (N.CrXBdr) by the boundary between two areas of different mineralization. We developed a semi-automatic process, robust to noise, low contrast and ring artefacts, to segment micro-cracks in 3D images. Since they are described as thin planar ellipses, we computed the best-fitting ellipsoids to access the cracks length (Cr.L) and width (Cr.w). We also estimated their thickness (Cr.Th) and volume (Cr.V). We present the average of the measures of all cracks in one sample of each group in Table 1. A large
Journal of Clinical Densitometry: Assessment of Skeletal Health
Body composition parameters LMI (total lean) (gr/m2) aLMI (gr/m2) FMI (Total fat) (gr/m2) % Truncal Fat
Tertile 1(!1.2) 17559 7384 12268 38
Tertile 2 (1.2e2.2)
Tertile 3 (O2.2)
383 15949 374 15997 382 187 6641 182 6683 186 648 9784 636 9374 646 1.5 33 1.5 33 1.5
P value 0.005 0.009 0.004 0.04
P value adjusted for age.
In the multiple regression analysis 2OHE1 /16OHE1, FEI and age were found to be important predictors of aLMI; 2OHE1 /16OHE1, and FEI for LMI ; 2OHE1 /16OHE1, 16OHE1 and FEI, for FMI ; 2OHE1 and FEI for % truncal fat. Conclusion: The decrease in estrogen catabolism (i.e. low total metabolites) and predominance of active pathway (i.e. lower 2:16 ratio) in addition to higher FEI is associated with higher BMI, % truncal fat and lean mass. Our results suggest that an estrogenic milieu created by a shift to the active pathway of estrogen metabolism and a reduction in the rate of estrogen catabolism, although associated with higher lean mass, is also associated with increased abdominal adiposity.
18 PEAK BONE GEOMETRY: POSITIVE INFLUENCE OF INTENSE WEIGHT-BEARING PHYSICAL ACTIVITY ON FEMUR MACRO ARCHITECTURE IN YOUNG WOMEN BETWEEN 17 AND 29 YEARS S. Bre´ban C. Chappard and C.L. Benhamou, 1INSERM Unit 658, Orleans Regional Hospital, Orleans, France; Rationale: Weight-bearing physical activity induces higher BMD values and higher bone geometry parameters. Peripheral Tomography and Magnetic Resonance Imaging are the main tools used to assess bone geometry parameters in
Volume 12, 2009