Cortical Bone Geometry Research Articles

Meagre effects of disuse on the human fibula are not explained by bone size or geometry.

The fibula supports only a small and highly variable proportion of shank compressive load (-8 to +19%), and little is known about other kinds of stresses. Hence, whilst effects of habitual loading on tibia are well-known, fibula response to disuse is difficult to predict. Therefore, we assessed fibular bone strength using peripheral quantitative computed tomography (pQCT) at 5% increments from 5 to 90% distal-proximal tibia length in nine participants with long-term spinal cord injury (SCI; age 39.2±6.2years, time since injury 17.8±7.4years), representing a cross-sectional model of long-term disuse and in nine able-bodied counterparts of similar age (39.6±7.8years), height and mass. There was no group difference in diaphyseal fibula total bone mineral content (BMC) (P=0.22, 95% CIs -7.4 % to -13.4 % and +10.9 % to +19.2 %). Site by group interactions (P<0.001) revealed 27 and 22% lower BMC in SCI at 5 and 90% (epiphyseal) sites only. Cortical bone geometry differed at mid and distal diaphysis, with lower endocortical circumference and greater cortical thickness in SCI than able-bodied participants in this region only (interactions both P<0.01). Tibia bone strength was also assessed; bone by group interactions showed smaller group differences in fibula than tibia for all bone parameters, with opposing effects on distal diaphysis geometry in the two bones (all Ps<0.001). These results suggest that the structure of the fibula diaphysis is not heavily influenced by compressive loading, and only mid and distal diaphysis are influenced by bending and/or torsional loads. The fibula is less influenced by disuse than the tibia, which cannot satisfactorily be explained by differences in bone geometry or relative changes in habitual loading in disuse. Biomechanical study of the shank loading environment may give new information pertaining to factors influencing bone mechanoadaptation.

Autoimmune arthritis deteriorates bone quantity and quality of periarticular bone in a mouse model of rheumatoid arthritis.

Periarticular osteoporosis near inflamed joints is a hallmark of early rheumatoid arthritis (RA). Here we show that rheumatic inflammation deteriorates the bone quality and bone quantity of periarticular bone, thereby decreasing bone strength and toughness in a mouse model of RA. Female BALB/c mice and SKG mice, a mutant mouse model of autoimmune arthritis on the BALB/c background, were used. At 12weeks of age, BALB/c mice underwent either Sham surgery or bilateral ovariectomy (OVX), and SKG mice underwent intraperitoneal injection of mannan to induce arthritis. Eight weeks later, the mice were killed and the femurs and tibias were subjected to micro-computed tomography, Fourier transform infrared (FTIR) spectroscopic imaging, X-ray diffraction, histology, and mechanical testing. SKG mice developed significant trabecular bone loss in both the distal metaphysis of the femur and the lumbar vertebral body, but the extent of the bone loss was more severe in the distal metaphysis. Neither SKG nor OVX mice exhibited changes in the geometry and matrix properties of the diaphysis of the femur, whereas SKG mice, but not OVX mice, did exhibit changes in these properties in the distal metaphysis of the femur. Bone strength and fracture toughness of the distal metaphysis of the tibia adjacent to the inflamed ankle joint were significantly decreased in SKG mice. Autoimmune arthritis induces periarticular osteoporosis, characterized by deterioration of cortical bone geometry and quality as well as by trabecular bone loss, leading to severe bone fragility in periarticular bone adjacent to inflamed joints.

Pueraria mirifica alleviates cortical bone loss in naturally menopausal monkeys.

Since the in vitro and in vivo anti-osteoporotic effects of Pueraria mirifica (PM) in rodents have been verified, its activity in menopausal monkeys was evaluated as required before it can be applicable for human use. In this study, postmenopausal osteoporotic monkeys were divided into two groups (five per group), and fed daily with standard diet alone (PMP0 group) or diet mixed with 1000 mg/kg body weight (BW) of PM powder (PMP1000 group) for 16 months. Every 2 months, the bone mineral density (BMD), bone mineral content (BMC) and bone geometry parameters (cortical area and thickness and periosteal and endosteal circumference) at the distal radius and proximal tibia were determined using peripheral quantitative computed tomography together with plasma and urinary bone markers. Compared with the baseline (month 0) values, the cortical, but not trabecular, BMDs and BMCs and the cortical area and thickness at the metaphysis and diaphysis of the radius and tibia of the PMP0 group continuously decreased during the 16-month study period. In contrast, PMP1000 treatment ameliorated the bone loss mainly at the cortical diaphysis by decreasing bone turnover, as indicated by the lowered plasma bone-specific alkaline phosphatase and osteocalcin levels. Generally, changes in the cortical bone geometry were in the opposite direction to the cortical bone mass after PMP1000 treatment. This study indicated that postmenopausal monkeys continuously lose their cortical bone compartment, and they have a higher possibility for long bone fractures. Oral PMP treatment could improve both the bone quantity (BMC and BMD) and quality (bone geometry).

Sclerostin does not play a major role in the pathogenesis of skeletal complications in type 2 diabetes mellitus

SummaryIn contrast to previously reported elevations in serum sclerostin levels in diabetic patients, the present study shows that the impaired bone microarchitecture and cellular turnover associated with type 2 diabetes mellitus (T2DM)-like conditions in ZDF rats are not correlated with changes in serum and bone sclerostin expression.IntroductionT2DM is associated with impaired skeletal structure and a higher prevalence of bone fractures. Sclerostin, a negative regulator of bone formation, is elevated in serum of diabetic patients. We aimed to relate changes in bone architecture and cellular activities to sclerostin production in the Zucker diabetic fatty (ZDF) rat.MethodsBone density and architecture were measured by micro-CT and bone remodelling by histomorphometry in tibiae and femurs of 14-week-old male ZDF rats and lean Zucker controls (n = 6/group).ResultsZDF rats showed lower trabecular bone mineral density and bone mass compared to controls, due to decreases in bone volume and thickness, along with impaired bone connectivity and cortical bone geometry. Bone remodelling was impaired in diabetic rats, demonstrated by decreased bone formation rate and increased percentage of tartrate-resistant acid phosphatase-positive osteoclastic surfaces. Serum sclerostin levels (ELISA) were higher in ZDF compared to lean rats at 9 weeks (+40 %, p < 0.01), but this difference disappeared as their glucose control deteriorated and by week 14, ZDF rats had lower sclerostin levels than control rats (−44 %, p < 0.0001). Bone sclerostin mRNA (qPCR) and protein (immunohistochemistry) were similar in ZDF, and lean rats at 14 weeks and genotype did not affect the number of empty osteocytic lacunae in cortical and trabecular bone.ConclusionT2DM results in impaired skeletal architecture through altered remodelling pathways, but despite altered serum levels, it does not appear that sclerostin contributes to the deleterious effect of T2DM in rat bone.

Impact of Non-Invasively Induced Motor Deficits on Tibial Cortical Properties in Mutant Lurcher Mice.

It has been shown that Lurcher mutant mice have significantly altered motor abilities, regarding their motor coordination and muscular strength because of olivorecebellar degeneration. We assessed the response of the cross-sectional geometry and lacuno-canalicular network properties of the tibial mid-diaphyseal cortical bone to motor differences between Lurcher and wild-type (WT) male mice from the B6CBA strain. The first data set used in the cross-sectional geometry analysis consists of 16 mice of 4 months of age and 32 mice of 9 months of age. The second data set used in the lacunar-canalicular network analysis consists of 10 mice of 4 months of age. We compared two cross-sectional geometry and four lacunar-canalicular properties by I-region using the maximum and minimum second moment of area and anatomical orientation as well as H-regions using histological differences within a cross section. We identified inconsistent differences in the studied cross-sectional geometry properties between Lurcher and WT mice. The biggest significant difference between Lurcher and WT mice is found in the number of canaliculi, whereas in the other studied properties are only limited. Lurcher mice exhibit an increased number of canaliculi (p < 0.01) in all studied regions compared with the WT controls. The number of canaliculi is also negatively correlated with the distance from the centroid in the Lurcher and positively correlated in the WT mice. When the Lurcher and WT sample is pooled, the number of canaliculi and lacunar volume is increased in the posterior Imax region, and in addition, midcortical H-region exhibit lower number of canaliculi, lacuna to lacuna distance and increased lacunar volume. Our results indicate, that the importance of precise sample selection within cross sections in future studies is highlighted because of the histological heterogeneity of lacunar-canalicular network properties within the I-region and H-region in the mouse cortical bone.

Crosstalk Between Muscle and Bone Via the Muscle-Myokine Irisin.

Several lines of evidence have recently established that skeletal muscle is an endocrine organ producing and releasing myokines acting in a paracrine or endocrine fashion. Among these, the newly identified myokine Irisin, produced by skeletal muscle after physical exercise, was originally described as molecule able to promote energy expenditure in white adipose tissue. Recently, it has been shown that the myokine Irisin affects skeletal metabolism in vivo. Thus, mice treated with a micro-dose of r-Irisin displayed improved cortical bone mass, geometry and strength, resembling the effect of physical activity in developing an efficient load-bearing skeleton. Further studies highlighted the autocrine effect of Irisin on skeletal muscle, and research performed in humans has definitively established that Irisin is a circulating hormone-like myokine, increased by physical activity. Albeit there are still few, since Irisin has been very recently discovered, herein are summarized the most relevant research findings published on this topic.

Low serum vitamin D is associated with higher cortical porosity in elderly men.

Bone loss at peripheral sites in the elderly is mainly cortical and involves increased cortical porosity. However, an association between bone loss at these sites and 25-hydroxyvitamin D has not been reported. To investigate the association between serum levels of 25-hydroxyvitamin D, bone microstructure and areal bone mineral density (BMD) in elderly men. A population-based cohort of 444 elderly men (mean ± SD age 80.2 ± 3.5 years) was investigated. Bone microstructure was measured by high-resolution peripheral quantitative computed tomography, areal BMD by dual-energy X-ray absorptiometry and serum 25-hydroxyvitamin D and parathyroid hormone levels by immunoassay. Mean cortical porosity at the distal tibia was 14.7% higher (12.5 ± 4.3% vs. 10.9 ± 4.1%, P < 0.05) whilst cortical volumetric BMD, area, trabecular bone volume fraction and femoral neck areal BMD were lower in men in the lowest quartile of vitamin D levels compared to the highest. In men with vitamin D deficiency (<25 nmol L-1 ) or insufficiency [25-49 nmol L-1 , in combination with an elevated serum level of parathyroid hormone (>6.8 pmol L-1 )], cortical porosity was 17.2% higher than in vitamin D-sufficient men (P < 0.01). A linear regression model including age, weight, height, daily calcium intake, physical activity, smoking vitamin D supplementation and parathyroid hormone showed that 25-hydroxyvitamin D independently predicted cortical porosity (standardized β = -0.110, R2 = 1.1%, P = 0.024), area (β = 0.123, R2 = 1.4%, P = 0.007) and cortical volumetric BMD (β = 0.125, R2 = 1.4%, P = 0.007) of the tibia as well as areal BMD of the femoral neck (β = 0.102, R2 = 0.9%, P = 0.04). Serum vitamin D is associated with cortical porosity, area and density, indicating that bone fragility as a result of low vitamin D could be due to changes in cortical bone microstructure and geometry.

Associations of insulin sensitivity with cortical bone geometry in healthy adult men

Associations of insulin sensitivity with cortical bone geometry in healthy adult men

The effect of local IL-4 delivery or CCL2 blockade on implant fixation and bone structural properties in a mouse model of wear particle induced osteolysis.

Modulation of macrophage polarization and prevention of CCL2-induced macrophage chemotaxis are emerging strategies to reduce wear particle induced osteolysis and aseptic total joint replacement loosening. In this study, the effect of continuous IL-4 delivery or bioactive implant coating that constitutively releases a protein inhibitor of CCL2 signaling (7ND) on particle induced osteolysis were studied in the murine continuous femoral intramedullary particle infusion model. Polyethylene particles with or without IL-4 were infused into mouse distal femurs implanted with hollow titanium rods using subcutaneous infusion pumps. In another experimental group, particles were infused into the femur through a 7ND coated rod. After 4 weeks, fixation of the implant was assessed using a pullout test. The volume of trabecular bone and the geometry of the local cortical bone were assessed by µCT and the corresponding structural properties of the cortical bone determined by torsional testing. Continuous IL-4 delivery led to increased trabecular bone volume as well as enhanced local bone geometry and structural properties, while 7ND implant coating did not have effect on these parameters. The results suggest that local IL-4 treatment is a promising strategy to mitigate wear particle induced osteolysis. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2255-2262, 2016.

Trabecular and cortical bone deficits are present in children and adolescents with cystic fibrosis

Osteopenia and increased fracture rates are well-recognized in adults with CF, but neither the specific contributions of cortical and trabecular bone deficits to bone fragility nor their presence in youth with CF are well-characterized. This study sought to characterize cortical and trabecular volumetric bone mineral density (vBMD), geometry, and biomechanical competence in children with CF and determine their relationship to growth, body composition, and disease severity. Peripheral quantitative computerized tomography (pQCT) measures of total, cortical, and trabecular vBMD, cortical, muscle, and fat cross-sectional areas (CSA), periosteal and endosteal circumferences, and the polar unweighted section modulus (Zp) of the tibia were converted to age- and tibial length-adjusted Z-scores in 97 CF and 199 healthy children (aged 8–21y). Effects of body composition and pulmonary function (forced expiratory volume in 1s, FEV1) upon pQCT outcomes were determined using linear regression. Children with CF (FEV1%-predicted: 84.4+19.7) had lower weight-, height-, BMI-, and whole body lean mass (LBM)-Z and tibial length. Females with CF had lower (p<0.01) total and trabecular vBMD; cortical, muscle, and fat CSA; Zp and periosteal circumference than females in the healthy reference group. These bone differences persisted after adjustment for BMI-Z and to a great extent following adjustment for muscle CSA. Males with CF had lower (p<0.01) cortical, muscle, and fat CSA and their trabecular vBMD deficit approached significance (p=0.069). Deficits were attenuated by adjustment for BMI-Z and to a greater extent adjustment for muscle CSA-Z. The relationship between FEV1%-predicted and pQCT outcomes persisted only in males following adjustment for age and BMI-Z. The CF cohort had lower tibial muscle CSA than expected for their LBM. In this relatively healthy, young CF cohort, deficits in trabecular and multiple cortical bone parameters were present. In females, deficits were greater at older ages and were not fully explained by alterations in body composition. In males worsening pulmonary function was associated with greater deficits that was not explained by increasing age or compromised nutritional status. The occurrence of these differences in CF youth highlights the importance of instituting measures to optimize peak bone mass early in the course of CF.

Advancing maternal age at childbirth is associated with less favourable trabecular bone mineral density and tibial cortical bone geometry in young adult male offspring

Advancing maternal age at childbirth is associated with less favourable trabecular bone mineral density and tibial cortical bone geometry in young adult male offspring

Effects of Habitual Physical Activity and Fitness on Tibial Cortical Bone Mass, Structure and Mass Distribution in Pre-pubertal Boys and Girls: The Look Study.

Targeted weight-bearing activities during the pre-pubertal years can improve cortical bone mass, structure and distribution, but less is known about the influence of habitual physical activity (PA) and fitness. This study examined the effects of contrasting habitual PA and fitness levels on cortical bone density, geometry and mass distribution in pre-pubertal children. Boys (n=241) and girls (n=245) aged 7-9years had a pQCT scan to measure tibial mid-shaft total, cortical and medullary area, cortical thickness, density, polar strength strain index (SSIpolar) and the mass/density distribution through the bone cortex (radial distribution divided into endo-, mid- and pericortical regions) and around the centre of mass (polar distribution). Four contrasting PA and fitness groups (inactive-unfit, inactive-fit, active-unfit, active-fit) were generated based on daily step counts (pedometer, 7-days) and fitness levels (20-m shuttle test and vertical jump) for boys and girls separately. Active-fit boys had 7.3-7.7% greater cortical area and thickness compared to inactive-unfit boys (P<0.05), which was largely due to a 6.4-7.8% (P<0.05) greater cortical mass in the posterior-lateral, medial and posterior-medial 66% tibial regions. Cortical area was not significantly different across PA-fitness categories in girls, but active-fit girls had 6.1% (P<0.05) greater SSIpolar compared to inactive-fit girls, which was likely due to their 6.7% (P<0.05) greater total bone area. There was also a small region-specific cortical mass benefit in the posterior-medial 66% tibia cortex in active-fit girls. Higher levels of habitual PA-fitness were associated with small regional-specific gains in 66% tibial cortical bone mass in pre-pubertal children, particularly boys.

Femoral bone structure in Otsuka Long-Evans Tokushima Fatty rats

ObjectivesType 2 diabetes mellitus (T2DM) increases fracture risk despite normal to high levels of bone mineral density. Bone quality is known to affect bone fragility in T2DM. The aim of this study was to clarify the trabecular bone microstructure and cortical bone geometry of the femur in T2DM model rats. MethodsFive-week-old Otsuka Long-Evans Tokushima Fatty (OLETF; n = 5) and Long-Evans Tokushima Otsuka (LETO; n = 5) rats were used. At the age of 18 months, femurs were scanned with micro-computed tomography, and trabecular bone microstructure and cortical bone geometry were analyzed. ResultsTrabecular bone microstructure and cortical bone geometry deteriorated in the femur in OLETF rats. Compared with in LETO rats, in OLETF rats, bone volume fraction, trabecular number and connectivity density decreased, and trabecular space significantly increased. Moreover, in OLETF rats, cortical bone volume and section area decreased, and medullary volume significantly increased. ConclusionsLong-term T2DM leaded to deterioration in trabecular and cortical bone structure. Therefore, OLETF rats may serve as a useful animal model for investigating the relationship between T2DM and bone quality.

Editorial: Putting the "Why" Back into Bone "Archytecture".

Editorial: Putting the "Why" Back into Bone "Archytecture".

Raloxifene improves skeletal properties in an animal model of cystic chronic kidney disease.

Patients with chronic kidney disease (CKD) have an increased risk of fracture. Raloxifene is a mild anti-resorptive agent that reduces fracture risk in the general population. Here we assessed the impact of raloxifene on the skeletal properties of animals with progressive CKD. Male Cy/+ rats that develop autosomal dominant cystic kidney disease were treated with either vehicle or raloxifene for five weeks. They were assessed for changes in mineral metabolism and skeletal parameters (microCT, histology, whole bone mechanics, and material properties). Their normal littermates served as controls. Animals with CKD had significantly higher parathyroid hormone levels compared to normal controls as well as inferior structural and mechanical skeletal properties. Raloxifene treatment resulted in lower bone remodeling rates and higher cancellous bone volume in the rats with CKD. While it had little effect on cortical bone geometry it resulted in higher energy to fracture and modulus of toughness values than vehicle-treated rats with CKD, achieving levels equivalent to normal controls. Animals treated with raloxifene had superior tissue-level mechanical properties as assessed by nanoindentation and higher collagen D-periodic spacing as assessed by atomic force microscopy. Thus, raloxifene can positively impact whole bone mechanical properties in CKD through its impact on skeletal material properties.

Association of Jumping Mechanography-Derived Indices of Muscle Function with Tibial Cortical Bone Geometry.

Jumping mechanography has been developed to estimate maximum voluntary muscle forces. This study assessed associations of jumping mechanography-derived force and power measurements with tibial cortical bone geometry, compared to other estimates of muscle mass, size, and function. Healthy men (n=181; 25-45years) were recruited in a cross-sectional, population-based sibling-pair study. Muscle parameters include isokinetic peak torque of the quadriceps, DXA-derived leg lean mass, mechanography-derived peak jump force and power, and pQCT-derived mid-tibial (66%) muscle cross-sectional area (CSA). Mid-tibial cortical bone parameters were assessed by pQCT. In age, height, and weight-adjusted analyses, jump force and power correlated positively with cortical bone area, cortical thickness, and polar strength-strain index (SSIp) (β=0.23-0.34, p≤0.001 for force; β=0.25-0.30, p≤0.007 for power) and inversely with endosteal circumference adjusted for periosteal circumference (ECPC) (β=-0.16, p<0.001 for force; β=-0.13, p=0.007 for power). Force but not power correlated with cortical over total bone area ratio (β=0.25, p=0.002). Whereas leg lean mass correlated with all cortical parameters except cortical over total bone area ratio (β=0.25-0.62, p≤0.004), muscle CSA only correlated with cortical bone area, periosteal circumference, and SSIp (β=0.21-0.26, p≤0.001), and quadriceps torque showed no significant correlations with the bone parameters. Multivariate models indicated that leg lean mass was independently associated with overall bone size and strength reflected by periosteal and endosteal circumference and SSIp (β=0.32-0.55, p≤0.004), whereas jump force was independently associated with cortical bone size reflected by ECPC, cortical thickness, and cortical over total bone area ratio (β=0.13-0.28; p≤0.002). These data indicate that jumping mechanography provides relevant information about the relationship of muscle with bone geometry.

Skeletal muscle and pediatric bone development.

The purpose of this review is to summarize the recent clinical findings surrounding the muscle-bone relationships in children, while considering muscle adiposity, endocrine factors, and lifestyle influences (i.e., diet and exercise) involved in pediatric musculoskeletal development. Positive relationships between cortical bone geometry and muscle mass, size and function have been reported. Prospective studies in particular have helped clarify some of the inconsistent relationships between muscle and cortical bone volumetric density. Muscle fat is associated with impaired glucose handling and muscular functionality, which may in turn have a downstream effect on cortical bone growth during adolescence. Lifestyle factors such as healthful diets and higher impact physical activities can promote optimal skeletal development by improving the muscular phenotype and endocrine profile. Muscle and bone are two intricately-related tissue types; however, factors such as sex, maturation, study design, and outcome measures studied can modify this relationship. Further research is warranted to understand the impact of muscle adiposity on cardiometabolic health, muscle function and, subsequently, pediatric musculoskeletal development and fracture risk. Following age-specific diet and physical activity recommendations should be a major focus in obtaining optimal muscle and bone development throughout maturation.

Greater association of peak neuromuscular performance with cortical bone geometry, bone mass and bone strength than bone density: A study in 417 older women

BackgroundWe evaluated which aspects of neuromuscular performance are associated with bone mass, density, strength and geometry. Methods417 women aged 60–94years were examined. Countermovement jump, sit-to-stand test, grip strength, forearm and calf muscle cross-sectional area, areal bone mineral content and density (aBMC and aBMD) at the hip and lumbar spine via dual X-ray absorptiometry, and measures of volumetric vBMC and vBMD, bone geometry and section modulus at 4% and 66% of radius length and 4%, 38% and 66% of tibia length via peripheral quantitative computed tomography were performed. The first principal component of the neuromuscular variables was calculated to generate a summary neuromuscular variable. Percentage of total variance in bone parameters explained by the neuromuscular parameters was calculated. Step-wise regression was also performed. ResultsAt all pQCT bone sites (radius, ulna, tibia, fibula), a greater percentage of total variance in measures of bone mass, cortical geometry and/or bone strength was explained by peak neuromuscular performance than for vBMD. Sit-to-stand performance did not relate strongly to bone parameters. No obvious differential in the explanatory power of neuromuscular performance was seen for DXA aBMC versus aBMD. In step-wise regression, bone mass, cortical morphology, and/or strength remained significant in relation to the first principal component of the neuromuscular variables. In no case was vBMD positively related to neuromuscular performance in the final step-wise regression models. ConclusionPeak neuromuscular performance has a stronger relationship with leg and forearm bone mass and cortical geometry as well as proximal forearm section modulus than with vBMD.

Alendronate does not prevent long bone fragility in an inactive rat model.

The lack of estrogen and inactivity are both important in the pathogenesis of osteoporosis in elderly women, and there have been no appropriate rodent studies to examine the effects of common bisphosphonates on these two components separately. We compared the efficacy of alendronate (ALN) on the long bones of aged female rats, which were sedentary, estrogen deficient, or both. The rats were either forced to remain in a sitting position or allowed to walk in standard cages with or without ALN administration. The 8-week experimental period began 5weeks after ovariectomy or sham surgery. Parameters of the hindlimb bones were determined by a three-point bending test, peripheral quantitative computed tomography, microfocus computed tomography, confocal laser Raman microspectroscopy, and dynamic histomorphometry. Regardless of ovariectomy, ALN was ineffective against the deterioration of breaking stress caused by sitting even though the trabecular bone mineral density was significantly higher in the sitting-ALN groups. Toughness was significantly deficient in the ovariectomy sitting-ALN group. This was in agreement with the bone geometry with a greater marrow space. Sitting also increased the mineral-to-matrix ratio and the carbonate-to-phosphate ratio, both indicative of aged bone. A greater loss of proteinaceous amide intensity compared with mineral intensity resulted in an increased mineral-to-matrix ratio in the presence of ALN. Sitting resulted in deficits in the quality and the geometry of cortical bone, resulting in fragility. The use of bisphosphonates, such as ALN, may provide a therapy best suited for osteoporotic individuals whose daily activity is not limited.

A new algorithm to improve assessment of cortical bone geometry in pQCT

High-resolution peripheral quantitative computed tomography (HR-pQCT) is now considered the leading imaging modality in bone research. However, access to HR-pQCT is limited and image acquisition is mainly constrained only for the distal third of appendicular bones. Hence, the conventional pQCT is still commonly used despite inaccurate threshold-based segmentation of cortical bone that can compromise the assessment of whole bone strength. Therefore, this study addressed whether the use of an advanced image processing algorithm, called OBS, can enhance the cortical bone analysis in pQCT images and provide similar information to HR-pQCT when the same volumes of interest are analyzed. Using pQCT images of European Forearm Phantom (EFP), and pQCT and HR-pQCT images of the distal tibia from 15 cadavers, we compared the results from the OBS algorithm with those obtained from common pQCT analyses, HR-pQCT manual analysis (considered as a gold standard) and common HR-pQCT analysis dual threshold technique. We found that the use of OBS segmentation method for pQCT image analysis of EFP data did not result in any improvement but reached similar performance in cortical bone delineation as did HR-pQCT image analyses. The assessments of cortical cross-sectional bone area and thickness by OBS algorithm were overestimated by less than 4% while area moments of inertia were overestimated by ~5–10%, depending on reference HR-pQCT analysis method. In conclusion, this study showed that the OBS algorithm performed reasonably well and it offers a promising practical tool to enhance the assessment of cortical bone geometry in pQCT.