Star Volume Research Articles

Multidetector-row computed tomography is useful to evaluate the therapeutic effects of bisphosphonates in glucocorticoid-induced osteoporosis

Osteoporosis is one of the major complications of glucocorticoid therapy. Osteoporosis is usually defined by the levels of bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DEXA); however, glucocorticoids often induce fractures in patients with normal BMD. Thus, novel diagnostic approaches are required. In this study, we examined whether multidetector-row computed tomography (MDCT) is useful to assess the bone status in glucocorticoid-induced osteoporosis (GIO). Because bisphosphonates have been proven to prevent bone fracture in GIO, we tried to detect the therapeutic effects of bisphosphonates in GIO by MDCT. Fifteen Japanese patients with immunoglobulin A nephropathy who had normal renal function were enrolled in this open-label randomized trial. Patients were randomly divided into three groups-calcitriol (VD), menatetrenone (VK), or bisphosphonate (Bis). Bone conditions were analyzed twice by three different methods-bone turnover markers, DEXA, and MDCT-at the start and 6 months after the start of therapy. Both bone markers and DEXA could not detect significant differences among the therapeutic groups; however, MDCT-based analyses detected the preventive effects of bisphosphonates in GIO. Compared to VD, Bis improved structural indices, such as bone volume fraction, trabecular separation, marrow star volume, and structure model index whereas the difference between VD and VK was not significant. Finite element analysis revealed that simulated fracture load in the Bis group was significantly improved. These findings suggested that MDCT-based assessment is superior to bone markers and/or DEXA in assessing the therapeutic effect of bisphosphonates on GIO.

Histomorphometric analysis of bone deposition at Ti implant surface dip-coated with hydroxyapatite (In vivo study)

Background: Synthetic hydroxyapatite,(Ca10(PO4)6(OH2) can directly bond to bones without infection and fibrous encapsulation, thus is regarded as bioactive and biocompatible. The aim of the study was the estimation of microarchitecture bone parameters include bone mass (gm/cm2) cortical bone width (mm), thread width (mm), marrow space star volume analysis (V*m) and osteoblast, osteocyte cell number. Materials and methods: Ninety-six (96) commercially pure titanium CpTi) used in this study, (48) implants were coated with HA by dipping coating and (48) implants were used as control. They were inserted in (32) Newzland white rabbits and followed for 2 & 6 weeks. Mechanical torque removal test and histomorphometric analysis of bone microarchiteture were performed for evaluation of osseointegration. Results: Results revealed, Torque values were increased with advancing time for coated and uncoated groups. And specifically dip coated implant showed high value in comparison to control. Histomorphometric analysis for bone parameters showed highly significant difference in overall contrasted groups of implant in 2nd and 6th week interval. Conclusion: Dip coating method is an alternative coating technique for dental implant to enhance better bone implant contact and improve osseointegration.

Soft diet causes greater alveolar osteopenia in the mandible than in the maxilla

ObjectiveTo investigate changes in the bony microstructure of the upper and lower alveolar bone during masticatory loading induced by soft diet feeding in growing rats. DesignThree-week-old male Wistar rats were randomly divided into two groups. Rats were fed with either pellets [control group (n=6)] or a soft diet [experimental group (n=6)] for nine weeks. 3D-microstructure of the alveolar bone of the first molar region (M1) was examined by micro-CT analysis. ResultsMicro-CT images showed increased marrow spaces of the inter-radicular alveolar bone around the rat mandibular M1 in the experimental group compared with that in the control group. The bone volume/tissue volume ratio, trabecular thickness, trabecular number, mean intercept length, trabecular width and trabecular star volume for the mandibular M1 inter-radicular alveolar bone were lower in the experimental group than in the control group. Marrow space star volume was increased in the experimental group compared with the control group. ConclusionsThese results suggest that alveolar osteopenia is more extensive in the mandible than the maxilla in rats that experience low masticatory loading during growth.

The Beneficial Use of Nigella Sativa Powder in the Healing of Different Portions of Extracted Tooth Socket: In Vivo Study

Bac k ground: Nigella sativa is so beneficial due to it’s content of over a hundred components such as aromatic oils, trace elements, vitamins and enzymes. It contains 58% of essential fatty acids including omega 6 and omega 3. These are necessary for the forming of Prostaglandin E1 which balances and strengthens the immune system giving it the power to prevent infections and allergies and control chronic illnesses. Blackseed oil also contains about 0.5 - 1.5% volatile oils including nigellone and thymochinone which are responsible for its anti-histamine, anti-oxidant, anti-infective and broncho-dilating effect. Aim o f the study: To evaluate the effect of Nigella sativa (powder and oil) on the healing process in different portions of rabbit socket by histomorphometric analysis of bone architecture parameters. Mat erials and Methods: The sample of the study consist of twenty rabbits, extract their upper two central incisors under general anesthesia. The left side filled once with Nigella sativa powder and once with Nigella sativa oil material, and the right side left for normal healing as a control group. The two sockets were sutured. The results were studied in intervals period 2 and 6 weeks, histologically and then assayed for histomorphometic analysis for trabecular width, trabecular number and the trabecular separa- tion Marrow space star volume analysis (V*m), Osteoblast, osteocyte, and blood vessels number, in coronal, middle and apical portions of extracted tooth socket. These parameters are derived from microscopic two dimension image measurements analyzer software program. Results: Histomorphometric analysis for variables of trabeculae width (thickness of trabeculae), trabecular separation and cortical thickness in three studied groups for coronal, middle and apical portions of socket showed significant differences in NgS powder and oil groups in comparison to control. Bone marrow star volume showed a significant variation between NgS powder and NgS oil in comparison to control, also bone marrow star volume showed decrease in it’s value with increment in healing period in all groups. Trabecular number and width shows to be higher in NgS powder group in all portions of the socket in comparisum to control and NgS oil groups at 2 and 6 weeks duration. Blood vessels’ number shows to be higher in middle portion in NgS powder group at 2 and 6 weeks duration in comparisum to NgS oil and control groups. Con clusion: Nigella sativa powder suggest to be more effective and enhancer in acceleration of bone formation than oil.

Biomaterial porosity determined by fractal dimensions, succolarity and lacunarity on microcomputed tomographic images

Porous structures are becoming more and more important in biology and material science because they help in reducing the density of the grafted material. For biomaterials, porosity also increases the accessibility of cells and vessels inside the grafted area. However, descriptors of porosity are scanty. We have used a series of biomaterials with different types of porosity (created by various porogens: fibers, beads …). Blocks were studied by microcomputed tomography for the measurement of 3D porosity. 2D sections were re-sliced to analyze the microarchitecture of the pores and were transferred to image analysis programs: star volumes, interconnectivity index, Minkowski–Bouligand and Kolmogorov fractal dimensions were determined. Lacunarity and succolarity, two recently described fractal dimensions, were also computed. These parameters provided a precise description of porosity and pores' characteristics. Non-linear relationships were found between several descriptors e.g. succolarity and star volume of the material. A linear correlation was found between lacunarity and succolarity. These techniques appear suitable in the study of biomaterials usable as bone substitutes.

Boundary element analysis for effective stiffness tensors: effect of fabric tensor determination method

Second-rank fabric tensors have been extensively used to describe structural anisotropy and to predict orthotropic elastic constants. However, there are many different definitions of, and approaches to, determining the fabric tensor. Most commonly used is a fabric tensor based on mean intercept length measurements, but star volume distribution and star length distribution are commonly used, particularly in studies of trabecular bone. Here, we investigate the effect of the fabric tensor definition on elastic constant predictions using both synthetic, idealized microstructures as well as a micrograph of a porous ceramic. We use an efficient implantation of a symmetric Galerkin boundary element method to model the mechanical response of the various microstructures, and also use a boundary element approach to calculate the necessary volume averages of stress and strain to obtain the effective properties of the media.

POROSIMETRY BY RANDOM NODE STRUCTURING IN VIRTUAL CONCRETE

Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT) approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of the aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. However, aggregate grain surfaces lead to anisotropy in porosity. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements. In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS), introduced earlier in IA&S (Stroeven et al., 2011b) and random node structuring (RaNoS) provide such information.

POROSIMETRY BY DOUBLE-RANDOM MULTIPLE TREE STRUCTURING IN VIRTUAL CONCRETE

Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT) approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. Unfortunately, aggregate grain surfaces lead to pore anisotropy. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements. In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS), presented herein, and random node structuring (RaNoS) provide such information. The latter method will be introduced in a next issue of IA&S.

POROSIMETRY BY DOUBLE-RANDOM MULTIPLE TREE STRUCTURING IN VIRTUAL CONCRETE

Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT) approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. Unfortunately, aggregate grain surfaces lead to pore anisotropy. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements. In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS), presented herein, and random node structuring (RaNoS) provide such information. The latter method will be introduced in a next issue of IA&S.

POROSIMETRY BY DOUBLE-RANDOM MULTIPLE TREE STRUCTURING IN VIRTUAL CONCRETE

Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT) approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. Unfortunately, aggregate grain surfaces lead to pore anisotropy. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements. In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS), presented herein, and random node structuring (RaNoS) provide such information. The latter method will be introduced in a next issue of IA&S.

Histomorphometric analysis of bone architecture parameters in socket of rabbit treated with Nigella Sativa

Background: Seeds of Nigella sativa are frequently used in folk medicine in the Middle East and some Asian countries for the promotion of good health and treatment of many ailments. The multiple uses of Nigella sativa in folk medicine encouraged many investigators to isolate the possible active components and to conduct in vivo and in vitro studies on laboratory animals and human beings in order to understand its therapeutic actions. The aim of this study is to evaluate the effect of Nigella Sativa when used as a powder and during oil application on healing process of extracted teeth sockets in different weeks. Materials and Methods: The sample of our study consists of Forty eight rabbits to extract their upper two central incisors under general anesthesia. The left side filled once with Nigella sativa powder and once with Nigella sativa oil material, and the right side left for normal healing as a control group. The two sockets were sutured. The results were studied in intervals period 1, 2, 4, and 6 weeks, histologically and radiographically. Results: Histomorphometric analysis for variables: trabecular width, trabecular number, trabecular separation, Marrow space star volume analysis, Osteoblast number, osteocyte number and blood vessels number for two sockets showed significant differences in NgS powder group in comparison to NgS oil group and both NgS groups in comparison to control. Bone marrow star volume showed a significant variation between NgS powder and NgS oil and in both NgS groups in comparison to control, also bone marrow star volume showed decrease in it’s value with increment in healing period in all groups, Cortical bone thickness records showed increment in NgS powder group in comparison to oil and in both groups in comparison to control with increment in periods of healing, Counting of osteoblast and osteocyte showed high number in both NgS (powder and oil) groups in comparison to control group. The increment in number detected in 2nd week and then decrease as increase in periods (4th and 6th weeks) and numerous blood vessels detected in 4th week’s duration in NgS powder groups in apical portion while it detected in 6th weeks in apical portion for oil group. Conclusion: Nigella sativa (powder or oil) seems to be bioactive materials that enhance differentiation and proliferation of progenitor cells to specialized bone formative cells, with acceleration of bone formation. (J Bagh Coll Dentistry 2012;24(1):45-51).

Volumes and Numbers of Intervillous Pores and Villous Domains in Placentas Associated with Intrauterine Growth Restriction and/or Pre-eclampsia

The intrauterine environment has an important influence on placental development. In pre-eclampsia (PE) and intrauterine growth restriction (IUGR), early remodelling of spiral arteries has repercussions for uteroplacental blood flow. The IUGR placenta exhibits compromised growth of villous trees, a smaller intervillous space and a lower diffusive conductance. Here, we test whether or not term placentas associated with PE or IUGR also exhibit changes in structural quantities (notably, sizes and numbers of intervillous pores and villous domains) pertinent to uteroplacental haemodynamics. Paraffin wax sections were sampled at random locations and orientations and structural quantities obtained by combining design-based stereological estimates of total and star volumes with model-based estimates of pore hydraulic diameters. Total volumes of intervillous pores and villi were estimated by point counting, total villous surface by intersection counting and star volumes by measuring point-sampled intercept lengths. Other quantities were derived secondarily and group estimates compared by two-way analysis of variance. We found significant main effects of IUGR but no main or interaction effects involving PE. In IUGR, there were fewer intervillous pores and these had larger hydraulic diameters. IUGR also produced fewer villous domains but these were constant in star volume and villi had a constant mean diameter and volume fraction. We concluded that IUGR compromises placental development by producing intervillous pores and villous trees different in size and shape from those in control and PE pregnancies. Calculations suggest that Darcian conductances in the intervillous space improve in IUGR but, in reality, placental performance is compromised by other physiological and structural constraints including the known decline in diffusive conductances.

Anisotropy in the Frontal Sinuses of Bighorn Sheep and Its Implications for Understanding Pneumatization

In bighorn sheep (Ovis canadensis), greatly expanded frontal sinuses overlie the endocranial cavity and enter the horncores. A number of bony struts further subdivide the sinuses. Previous workers have suggested that the struts function as shock absorbers and/or strengthen the sinus against the forces of head butting. Under both scenarios, it is predicted that the struts should be oriented parallel to typical loads applied to the horns. In order to test this hypothesis, skulls of male O. canadensis were CT scanned, and structural anisotropy for the struts within the frontal sinus was estimated using the star volume distribution method. Measurements were taken at the base and midpoint of the horncores. Strut orientations were highly anisotropic. Struts were oriented parallel to the long axis of the horn at its base and oriented medio‐laterally distally. These results are contrary to expectations, suggesting that sinus morphology within O. canadensis is not primarily shaped by applied loads. Instead, the orientation of the struts may simply reflect the direction of expansion of the pneumatic diverticulum during pneumatization of the skull. Funded by SICB and an NSF GRF.

A Simple Way to Improve Anatomical Mapping of Functional Brain Imaging

Advances in functional neuroimaging studies have led to the need for improved anatomical precision to face with more and more specific challenges. Nevertheless, functional magnetic resonance imaging (MRI) (fMRI) suffers from geometrical distortions, which limit the matching between functional and anatomical data necessary to interpret fMRI results. The "FieldMap" method is the most widely used technique to correct for geometrical distortions but in some cases cannot be applied or provides unsatisfactory results. The objective of this study is thus to provide a very simple alternative method for distortion correction and to demonstrate its efficiency. This correction relies on the nonlinear registration of echo-planar imaging (EPI) acquisitions onto their corresponding undistorted non-EPI T2 Star volume, and was tested on two independent groups of subjects undertaking the same paradigm but scanned with distinct EPI sequences. This procedure was found to considerably decrease the mismatch between functional and anatomical data in both groups, as revealed through several quantitative and qualitative measures on both EPI volumes and activation maps. This study describes a simple, rapid, and easily implementable method to significantly improve neuroanatomical accuracy of fMRI results localization, which may be relevant for future neuroimaging studies.

Concrete porosimetry: Aspects of feasibility, reliability and economy

Abstract The opening operator of mathematical morphology is applied to section images in this paper for the assessment of pore characteristics, such as the size distribution, and critical pore size, in cement pastes. Moreover, the mean free spacing parameter is demonstrated as reflecting pore depercolation during cement maturation. This approach is compared with other popular methods for serving this purpose, encompassing the experimental technique of mercury intrusion porosimetry (MIP), Wood’s metal intrusion porosimetry (WMIP), the conventional method of image analysis by area histogram and a direct 3D approach by a simulation model. The comparison study reveals that the opening distribution technique is superior in terms of feasibility, reliability and economy; realistic and relevant structural information on pore space in cement pastes is obtained. Nevertheless, star volume measurements applied to section images are referred to as an interesting alternative to the proposed method. The proper characterization of pore size distribution, and assessment of critical pore size, and delineation of percolated porosity zones are of significant importance to permeability prediction of cementitious materials and thereby to durability studies of the materials.

Cancellous Bone Volume Is an Indicator for Trabecular Bone Connectivity in Dialysis Patients

A new assessment system for bone histology, termed the turnover-mineralization-volume system, is advocated for patients with chronic kidney disease-related mineral and bone disorder. The system measures cancellous bone volume (BV/TV) as a third major evaluation axis; however, the physiologic significance of BV/TV remains unclear. Conventional bone histomorphometry was performed in 75 iliac bone samples obtained from dialysis patients. In 47 of the 75 samples, the remaining samples were subjected to direct microfocus x-ray computed tomographic observation. Quantitative morphologic examinations, including micro-bone mineral densitometry, and marrow space star volume, Euler number, and node-strut analyses, were performed in the virtual three-dimensional space reconstructed from the microfocus x-ray computed tomographic images. The levels of BV/TV were comparable in each of the conventional bone histomorphometric criteria. No significant correlations were found between BV/TV and other parameters. Two- and three-dimensional BV/TVs were significantly correlated with cancellous bone mass but not with cortical bone thickness or cortical bone mass. Two- and three-dimensional BV/TVs were significantly correlated with trabecular bone connectivity as determined by marrow space star volume, Euler number, and node-strut analyses. In dialysis patients, BV/TV is not dependent on bone turnover or bone mineralization. BV/TV is unlikely to indicate the balance between bone formation and bone resorption. Instead, it reflects trabecular bone connectivity, and improved trabecular bone connectivity is physiologically beneficial in terms of bone quality. The turnover-mineralization-volume system offers an advantage over the conventional system for the assessment of bone quality.

The Application of Stereological Methods for Estimating Structural Parameters in the Human Heart

This study describes and exemplifies generally applicable design-based stereological methods for obtaining quantitative estimates of the numbers and sizes of capillaries, cardiomyocytes, and cardiomyocyte nuclei in immersion-fixed human left ventricles (N = 6). The design-based stereological methods are valid in all cardiac investigations onto quantifying changes in structure and function as seen under various conditions such as during development, aging, hypertrophy, and following ischemia/reperfusion. The applied principles of unbiased stereology were as follows: 1) uniform random sampling was taken at all levels, also in respect to orientations, for estimates of length and mean sizes. 2) All global structural quantities were estimated as total quantity = density x volume of the left ventricle. As an example, the left ventricle contains 1.5 x 10(9) capillaries with a total length of just below 200 km. 3) Stereological methods were used for estimating the volume density, surface area density, and length density of capillaries and cardiomyocytes. The numerical density of cardiomyocyte nuclei and capillaries was estimated, using the optical and physical disector, respectively. 4) In all local quantities, "size" was estimated either directly, using unbiased estimators to obtain the average individual size and size distribution parameters, or indirectly, using the relationship that: average size = total quantity/total number. In the six hearts constituting this study, we observed the anticipated correlation between left ventricular volume and global estimates such as total number of capillaries. There were no correlation between local quantities and total left ventricular volume (e.g., average star volume of individual cardiomyocytes).

Stereological study of the effects of Doxycycline on hyperoxic lung injury In neonatal rats

Objective To explore the influence and potential protective effects of non-specific panMetrix Metalloproteinases(MMPs) inhibitor Doxycycline on hyperoxic lung injury and lung development in neonatal rats.Methods Neonatal SD rats were divided into 4 groups randomly within 12 hours after birth:air with normal saline(AN),air with doxycycline(AD),hyperoxia with normal saline(ON),and hyperoxia with doxycycline group(OD).Hyperoxia groups(ON and OD) were exposed to ≥90% O2.Doxycycline 20 mg/kg or equal volume of 0.9% saline(Doxycycline concentration 2 mg/ml) was administered by gastric gavage,twice daily from day 1 to experimental day,but it didn't exceed 14 days.Stereological study was carried out at day 1,3,7,14 and 21 after birth.Results Enlarged mean alveolar area was noted both in hyperoxia and Doxycycline groups.OD group had larger star volume than ON group on day 14.Except ON group,all other groups had increased alveolar septum and the condition was worsened by hyperoxia with Doxycycline.The percentage of collagen in lung parenchymal tissue in ON group increased persistently.This increasing trend was stopped in OD group on day 14,and collagen percentage had no significantly difference between OD and AN groups on day 14 and 21.Conclusion Both hyperoxia and Doxycycline influence neonatal lung development,percentage of coUgen in lung parenchymai can be reduced by Doxycycline in hyperoxic lung injury. Key words: Rats,neonatal; Lung injury; Stereology; Hyperoxia; Doxycycline

Improved estimates of percolation and anisotropic permeability from 3‐D X‐ray microtomography using stochastic analyses and visualization

X‐ray microtomography (micro‐CT) with micron resolution enables new ways of characterizing microstructures and opens pathways for forward calculations of multiscale rock properties. A quantitative characterization of the microstructure is the first step in this challenge. We developed a new approach to extract scale‐dependent characteristics of porosity, percolation, and anisotropic permeability from 3‐D microstructural models of rocks. The Hoshen‐Kopelman algorithm of percolation theory is employed for a standard percolation analysis. The anisotropy of permeability is calculated by means of the star volume distribution approach. The local porosity distribution and local percolation probability are obtained by using the local porosity theory. Additionally, the local anisotropy distribution is defined and analyzed through two empirical probability density functions, the isotropy index and the elongation index. For such a high‐resolution data set, the typical data sizes of the CT images are on the order of gigabytes to tens of gigabytes; thus an extremely large number of calculations are required. To resolve this large memory problem parallelization in OpenMP was used to optimally harness the shared memory infrastructure on cache coherent Non‐Uniform Memory Access architecture machines such as the iVEC SGI Altix 3700Bx2 Supercomputer. We see adequate visualization of the results as an important element in this first pioneering study.

Comparison of Quantitative Cancellous Bone Connectivity Analyses at Two- and Three-Dimensional Levels in Dialysis Patients

Assessment of cancellous bone connectivity has the potential to aid in predicting fracture risk. Today, cancellous bone connectivity is generally assessed using bone sections obtained from biopsy. However, how reliably such two-dimensional (2-D) analyses visualize the 3-D properties has not been evaluated. Biopsied iliac bone samples were obtained from 47 chronic hemodialysis patients. Bone samples were observed using a microfocus X-ray computed tomography (microCT) system en bloc, and the cancellous bone microstructure was quantitatively assessed at both the 2- and 3-D levels. Cancellous bone microarchitecture was successfully reconstructed from the data obtained by the microCT system. Most of the results from node-strut analysis (NSA) revealed no statistically significant correlations between the 2- and 3-D analyses, with the exception that the number of nodes (N.Nd/TV) showed a mild but significant correlation. In contrast, the marrow space star volumes (V*m) of the 2- and 3-D analyses were highly correlated. NSA parameters including N.Nd/TV showed significant correlations with V*m at the 3-D level. In conclusion, V*m values were similar in the 2- and 3-D analyses, while most of the 2-D NSA parameters did not reflect the 3-D ones. Since V*m and most of the NSA parameters were correlated in the 3-D analyses, 2-D NSA would seem to have serious limitations for the assessment of cancellous bone microstructural properties. Further studies will thus be needed to establish appropriate methods for assessing cancellous bone connectivity in clinical practice.