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In vivo assessment of trabecular bone structure with 3D computed tomography and local reconstruction
Bone Vol. 19, No. 3, Supplement September 1996:1293-1698
The 7th International
71 EFFECT
Congress
Abstracts of Bone Morphometry
147s
73 OF
CLODRONATE
ON
CORTICAL
BONE
IN
OVARIECTOMIZED RATS. KKippo, L. Lauren, R. Gmnmiemi, Z. Peng*. P. Kuurtamo, R. Selhnan, and K. Valnlnen’. Leiras @, 20101 Tnrku and University of Oulu, Department of Anatomy’, 90220 Oulu, Finland.
ILIAC CREST PERIOSTEUM RESPONDS TO THE LEVEL PHYSICAL ACTIVITY IN HUMAN ADULTS. MH Lafaae-Proust. L Vito. J Massardier. S Palle. C Alexandre. LBTO, Faculte de Medecine, ST Etienne, France.
OF
regimens of C markedly increased the bending strength of femoral shaft to the level of age-matched Sham rats. It is concluded that estrogen deficiency stinndated bone turnover in adult rats leading to cortical osteopenia and decreased bone strength in femoral shaft. Clodronate treatment, started 4 months after ovariectorny and continued for 3 or 6 months, reduced cortical osteopenia and induced a favourable effect on bending strength of tibia1 and femoral shafts.
It is currently admitted that adult periosteum is mainly fibrous and only active in response to pathologic stimuli. The aim of our study was to evaluate periosleum activity on bone biopsies in human adults whose physical activity had been assessed during previous experiments 1. 2. Two groups of subjects were studied: an iliac crest bone biipsy was performed on a first arouo of 20 heatlhv male volunteers [mean aae: 66.7k5.1) whose level of pi;ysi&tl activity was evaluated with a‘quest&naire and physical fiiness with the measurement of maximal oxygen uptake (\iOpmax) on a bicycle ergometer. The higher the \iOpmax the higher the duration of exercise per week. The second group was constituled bv 8 heaithv male volunteers (32.8k4.7 y-old) who t&de&en1 en iliac crest bone biopsy-before and after a 120-d bedrest exoerimenl. Bone samoles were embedded in MMA resin and quantitative histomorphometry was carried out on both periosleum. Osleoclasts were visualized with hisloenzymology (TRAP). Osteoid surface/ES, (OS/es) Eroded Suface/BS (ES/BS). number of osteoclastsl Bone perimeter, Osteoclastic Surface (Oc S/ES) Osteoid Thickness (OTh), Periosteum Thickness (PTh) were measured. In the first group we found a linear relationship between PTh and COOpmax (Y= 48.7x762.4, rG0.7, PcO.001) end a polynomialrelationshipbetween Oc S/BS and vO2max (y = 43.0 -55.1x+58.9 x2, rc0.6. pcO.05). These latter data filled in well wilh the decrease in cortical thickness observed in subjects exercising more than 6 hrs/wk. In the second group we found the following results in the outer periosteum(expressedBSmear&D, #p
72
74
The effect of clodronate on tibia1 and femoral diaphyseal cortical bone dynamic and static morphometry and bone strength was investigated in ovariectomized (OVX) Sprague-Dawley rats. Operation was carried out at the age of 6 months. After 4 months, the OVX rats were given S.C. either clodronate (C) or a vehicle (Ve) once a week for 3 or 6 months, the cumulative doses of both dosing regimens being 36, 84 and 300 mglkg. The Sham rats were given S.C. Ve and served as age-matched controls of 10, 13 and 16 months. Ovariectomy alone or combined with C did not affect the terminal histomotphometric indices of periosteal (Ps) bone formation or mineralization (O.Wi, %L.Pm, MARl, BFRIBS. Mlt) in tibia1 diaphysis analyzed based on an interlabel time (1r.L.t) of 21 days at the end of the study. Ps.MARl of femoral mid-diaphysis was also unaffected by OVX and C. PsMAR2 analyzed for the entire study period was increased in tibia1 diaphysis at 4, 7 and 10 months after OVX (1r.L.t 100, 185, and 267 days, respectively) and in femoral diaphysis at 4 months after OVX. Ps.MAR2 of tibia1 diaphysis was at the same level as in the age-matched OVXlVe rats at each dose level of C. The cortical width of tibia1 and femoral diaphyses was above the level of the age-matched OVXlVe group after C. The per cent cross-sectional cortical bone area (%Ct.Ar) decreased in tibia and femur as a result of estrogen deficiency at 7 and 10 months after operation. Treatment with C increased %Ct.Ar in comparison to OVXlVe groups. C decreased the OVX induced enlargement of per cent marrow area in tibia and femur. Ovariectomy as such increased the maximum load in three-point bending of the tibia1 shaft.
Further dose-dependent increases in the bending strength were found after C. Weakening of femoral shaft was not found until 7 months after OVX. Both dosing
RECOVERY OF LUMBAR VERTBRAL THE SECOND LACY-ATION IN RATS
CANCELLOUS
M. Kncisscl, B. Bowman, S.C. Miller Divtston of Radiobiology, University of UtahSalt
BONE
AFTER
IN VW0 ASSESSMENT STRUCTURE
Lake City, Utah,(USA)
A rcproductivc cycle m mammals alters the endocrine enviroment as well as calcium homcostasis with some significant effects on osseous tissues. Thcrc are some skeletal sites in the virgin female rat that have a large amount of cancellous bone, most of which is resorbed during the first lactation. The purpose of this study was to determine the extent of axial skeletal reconstitution following the second lactation. Sprague-Dawlcy rats, 98 days old at then first mating, were allowed to complete 2 reproductive cycles and then sacrificed at the end of the second lactation and also at 2, 4 and 6 weeks following the 21 days of lactating. A group 01 unmated ammals which wcrc the same age as the 6 week recovery group was also included. Evaluation of cancellous bone in the lumbar vertcbme was performed using semiautomatic image analysis and included bone volume, tmbccular number, thickness, and separation, nodal analysis and lnbecular bone pattcm factor. The bone volume was significantly lower in 0 and 2 weeks recovery groups compared to the other groups; however thcrc was no significant difference between the 4 and 6 weeks recovery groups and the unmated rats. Compared to the latter the trabecular number was significanly smaller in all recovery groups and the trabecular sepamtton significantly higher in the 0, 2, and 4 weeks recovery groups. The trabecular thickness was smaller in the 0 (significant) and 2 weeks recovery groups and higher in the 4 (significant) and 6 weeks recovery groups. The nodal analysis showed significantly greater numbers of freeto-free and node-to-free struts, and significantly smaller numbers of node to node struts in the 2 week recovery group compared to the other groups. The trabecular bone pattern factor was also significantly higher in the 2 week recovery group compared to all other groups. The pattern of maternal bone changes during the second lactation appears to continue into the first weeks after weaning shown by the changes in the structural parameters, indicatmg a decreased connectivity at the 2 week time period. Skeletal reconstitution in the 4 and 6 weeks groups is characterized by a significantly increased bone volume, a thickening of tmbeculae and increased connectivity. These changes would serve to reconstitute the structural integrity of the maternal skeleton and also prepare the skeleton for the next reproductive cycle.
OF TRABECULAR
WITH 3D COMPUTED
BONE
TOMOGRAPHY
AND LOCAL RECONSTRUCTION A. Laib T. Hildebrand, P. Riiegsegger -9 Institute for Biomedical Engineering, University and ETH Zurich (Switzerland) To investigate the complex three dimensional trabecular bone structure in t&o, a SD-pQCT has been built at our institute, which is able to perform non-invasive bone biopsies with a resolution of 165 pm. With newly developed methods the bone structure is extracted from the 3D-pQCT images and morphometric parameters are determined. In a small group of volunteers the reproducibility of this procedure was assessed. It was found that stuctural quantities like BViTV, Tb.N and Tb.Sp have a long-term reproducibility of less than 0.4% which is comparable to the best bone densitometric procedures. A meaningful quantitation of Tb.Th requires a higher spatial resolution. We show that an isotropic resolution of about 100 pm is sufficient to restore true values for Tb.Th. A resolution of 100 pm in L&O, and at an acceptable radiation dose, is achievable with local computed tomography. Hereby exact density information is lost, but the structural content of the data is fully preserved; this was proven with comparitative measurements of the same bone samples in a pCT-system (14 pm resolution) and the above mentionned system for in viva measurements. With the new technique of local tomography it is therefore possible to perform precise 3D bone structure analysis in patients with a radiation dose below 3 mSv.
The 7th International
71 EFFECT
Congress
Abstracts of Bone Morphometry
147s
73 OF
CLODRONATE
ON
CORTICAL
BONE
IN
OVARIECTOMIZED RATS. KKippo, L. Lauren, R. Gmnmiemi, Z. Peng*. P. Kuurtamo, R. Selhnan, and K. Valnlnen’. Leiras @, 20101 Tnrku and University of Oulu, Department of Anatomy’, 90220 Oulu, Finland.
ILIAC CREST PERIOSTEUM RESPONDS TO THE LEVEL PHYSICAL ACTIVITY IN HUMAN ADULTS. MH Lafaae-Proust. L Vito. J Massardier. S Palle. C Alexandre. LBTO, Faculte de Medecine, ST Etienne, France.
OF
regimens of C markedly increased the bending strength of femoral shaft to the level of age-matched Sham rats. It is concluded that estrogen deficiency stinndated bone turnover in adult rats leading to cortical osteopenia and decreased bone strength in femoral shaft. Clodronate treatment, started 4 months after ovariectorny and continued for 3 or 6 months, reduced cortical osteopenia and induced a favourable effect on bending strength of tibia1 and femoral shafts.
It is currently admitted that adult periosteum is mainly fibrous and only active in response to pathologic stimuli. The aim of our study was to evaluate periosleum activity on bone biopsies in human adults whose physical activity had been assessed during previous experiments 1. 2. Two groups of subjects were studied: an iliac crest bone biipsy was performed on a first arouo of 20 heatlhv male volunteers [mean aae: 66.7k5.1) whose level of pi;ysi&tl activity was evaluated with a‘quest&naire and physical fiiness with the measurement of maximal oxygen uptake (\iOpmax) on a bicycle ergometer. The higher the \iOpmax the higher the duration of exercise per week. The second group was constituled bv 8 heaithv male volunteers (32.8k4.7 y-old) who t&de&en1 en iliac crest bone biopsy-before and after a 120-d bedrest exoerimenl. Bone samoles were embedded in MMA resin and quantitative histomorphometry was carried out on both periosleum. Osleoclasts were visualized with hisloenzymology (TRAP). Osteoid surface/ES, (OS/es) Eroded Suface/BS (ES/BS). number of osteoclastsl Bone perimeter, Osteoclastic Surface (Oc S/ES) Osteoid Thickness (OTh), Periosteum Thickness (PTh) were measured. In the first group we found a linear relationship between PTh and COOpmax (Y= 48.7x762.4, rG0.7, PcO.001) end a polynomialrelationshipbetween Oc S/BS and vO2max (y = 43.0 -55.1x+58.9 x2, rc0.6. pcO.05). These latter data filled in well wilh the decrease in cortical thickness observed in subjects exercising more than 6 hrs/wk. In the second group we found the following results in the outer periosteum(expressedBSmear&D, #p
72
74
The effect of clodronate on tibia1 and femoral diaphyseal cortical bone dynamic and static morphometry and bone strength was investigated in ovariectomized (OVX) Sprague-Dawley rats. Operation was carried out at the age of 6 months. After 4 months, the OVX rats were given S.C. either clodronate (C) or a vehicle (Ve) once a week for 3 or 6 months, the cumulative doses of both dosing regimens being 36, 84 and 300 mglkg. The Sham rats were given S.C. Ve and served as age-matched controls of 10, 13 and 16 months. Ovariectomy alone or combined with C did not affect the terminal histomotphometric indices of periosteal (Ps) bone formation or mineralization (O.Wi, %L.Pm, MARl, BFRIBS. Mlt) in tibia1 diaphysis analyzed based on an interlabel time (1r.L.t) of 21 days at the end of the study. Ps.MARl of femoral mid-diaphysis was also unaffected by OVX and C. PsMAR2 analyzed for the entire study period was increased in tibia1 diaphysis at 4, 7 and 10 months after OVX (1r.L.t 100, 185, and 267 days, respectively) and in femoral diaphysis at 4 months after OVX. Ps.MAR2 of tibia1 diaphysis was at the same level as in the age-matched OVXlVe rats at each dose level of C. The cortical width of tibia1 and femoral diaphyses was above the level of the age-matched OVXlVe group after C. The per cent cross-sectional cortical bone area (%Ct.Ar) decreased in tibia and femur as a result of estrogen deficiency at 7 and 10 months after operation. Treatment with C increased %Ct.Ar in comparison to OVXlVe groups. C decreased the OVX induced enlargement of per cent marrow area in tibia and femur. Ovariectomy as such increased the maximum load in three-point bending of the tibia1 shaft.
Further dose-dependent increases in the bending strength were found after C. Weakening of femoral shaft was not found until 7 months after OVX. Both dosing
RECOVERY OF LUMBAR VERTBRAL THE SECOND LACY-ATION IN RATS
CANCELLOUS
M. Kncisscl, B. Bowman, S.C. Miller Divtston of Radiobiology, University of UtahSalt
BONE
AFTER
IN VW0 ASSESSMENT STRUCTURE
Lake City, Utah,(USA)
A rcproductivc cycle m mammals alters the endocrine enviroment as well as calcium homcostasis with some significant effects on osseous tissues. Thcrc are some skeletal sites in the virgin female rat that have a large amount of cancellous bone, most of which is resorbed during the first lactation. The purpose of this study was to determine the extent of axial skeletal reconstitution following the second lactation. Sprague-Dawlcy rats, 98 days old at then first mating, were allowed to complete 2 reproductive cycles and then sacrificed at the end of the second lactation and also at 2, 4 and 6 weeks following the 21 days of lactating. A group 01 unmated ammals which wcrc the same age as the 6 week recovery group was also included. Evaluation of cancellous bone in the lumbar vertcbme was performed using semiautomatic image analysis and included bone volume, tmbccular number, thickness, and separation, nodal analysis and lnbecular bone pattcm factor. The bone volume was significantly lower in 0 and 2 weeks recovery groups compared to the other groups; however thcrc was no significant difference between the 4 and 6 weeks recovery groups and the unmated rats. Compared to the latter the trabecular number was significanly smaller in all recovery groups and the trabecular sepamtton significantly higher in the 0, 2, and 4 weeks recovery groups. The trabecular thickness was smaller in the 0 (significant) and 2 weeks recovery groups and higher in the 4 (significant) and 6 weeks recovery groups. The nodal analysis showed significantly greater numbers of freeto-free and node-to-free struts, and significantly smaller numbers of node to node struts in the 2 week recovery group compared to the other groups. The trabecular bone pattern factor was also significantly higher in the 2 week recovery group compared to all other groups. The pattern of maternal bone changes during the second lactation appears to continue into the first weeks after weaning shown by the changes in the structural parameters, indicatmg a decreased connectivity at the 2 week time period. Skeletal reconstitution in the 4 and 6 weeks groups is characterized by a significantly increased bone volume, a thickening of tmbeculae and increased connectivity. These changes would serve to reconstitute the structural integrity of the maternal skeleton and also prepare the skeleton for the next reproductive cycle.
OF TRABECULAR
WITH 3D COMPUTED
BONE
TOMOGRAPHY
AND LOCAL RECONSTRUCTION A. Laib T. Hildebrand, P. Riiegsegger -9 Institute for Biomedical Engineering, University and ETH Zurich (Switzerland) To investigate the complex three dimensional trabecular bone structure in t&o, a SD-pQCT has been built at our institute, which is able to perform non-invasive bone biopsies with a resolution of 165 pm. With newly developed methods the bone structure is extracted from the 3D-pQCT images and morphometric parameters are determined. In a small group of volunteers the reproducibility of this procedure was assessed. It was found that stuctural quantities like BViTV, Tb.N and Tb.Sp have a long-term reproducibility of less than 0.4% which is comparable to the best bone densitometric procedures. A meaningful quantitation of Tb.Th requires a higher spatial resolution. We show that an isotropic resolution of about 100 pm is sufficient to restore true values for Tb.Th. A resolution of 100 pm in L&O, and at an acceptable radiation dose, is achievable with local computed tomography. Hereby exact density information is lost, but the structural content of the data is fully preserved; this was proven with comparitative measurements of the same bone samples in a pCT-system (14 pm resolution) and the above mentionned system for in viva measurements. With the new technique of local tomography it is therefore possible to perform precise 3D bone structure analysis in patients with a radiation dose below 3 mSv.