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The 1994 WHO criterion of a T-score ≤ -2.5 for densitometric osteoporosis was chosen because it results in a prevalence commensurate with the observed lifetime risk of fragility fractures in Caucasian women aged ≥ 50 years. Due to the much lower risk of fragility fracture among East Asians, the application of the conventional WHO criterion to East Asians leads to an over inflated prevalence of osteoporosis, particularly for spine osteoporosis. According to statistical modeling and when a local BMD reference is used, we tentatively recommend the cutpoint values for T-score of femoral neck, total hip, and spine to be approximately -2.7, -2.6, and -3.7 for Hong Kong Chinese women. Using radiographic osteoporotic vertebral fracture as a surrogate clinical endpoint, we empirically demonstrated that a femoral neck T-score of -2.77 for Chinese women was equivalent to -2.60 for Italian women, a spine T-score of -3.75 for Chinese women was equivalent to -2.44 for Italian women, and for Chinese men a femoral neck T-score of -2.77 corresponded to spine T-score of -3.37. For older Chinese men, we tentatively recommend the cutpoint values for T-score of femoral neck, total hip, and spine to be approximately -2.7, -2.6, and -3.2. With the BMD reference published by IKi et al. applied, T-score of femoral neck, total hip, and spine of -2.75, -3.0, and -3.9 for Japanese women will be more in line with the WHO osteoporosis definition. The revised definition of osteoporosis cutpoint T-scores for East Asians will allow a more meaningful international comparison of disease burden., (© 2023. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

The 2013 ISCD consensus recommended a Caucasian female reference database for T-score calculation in men, which says "A uniform Caucasian (non-race adjusted) female reference database should be used to calculate T-scores for men of all ethnic groups." However, this statement was recommended for the US population, and no position was taken with respect to BMD reference data or ethnicity matching outside of the USA. In East Asia, currently, a Japanese BMD reference database is universally adopted in Japan for clinical DXA diagnosis, while both local BMD and Caucasian BMD reference databases are in use in Mainland China, South Korea, Taiwan, and Singapore. In this article, we argue that an ethnicity- and gender-specific BMD database should be used for T-score calculations for East Asians, and we list the justifications why we advocate so. Use of a Caucasian BMD reference database leads to systematically lower T-scores for East Asians and an overestimation of the prevalence of osteoporosis. Using a female BMD reference database to calculate T-scores for male patients leads to higher T-score values and an underestimation of the prevalence of osteoporosis. Epidemiological evidence does not support using a female BMD reference database to calculate T-scores for men. We also note that BMD reference databases collected in Asia should be critically evaluated for their quality., (© 2023. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

The prevalence and severity of spine degenerative changes have been noted to be lower among older Chinese women than among older Caucasian women. Spine degenerative changes associated with marginal osteophytosis, trabecular thickening, subchondral sclerosis, facet joint arthrosis, and disc space narrowing can all lead to artificially higher spine areal bone mineral density (BMD). The lower prevalence and severity of spine degeneration have important implications for the interpretation of spine areal BMD reading for Chinese women. With fewer contributions from spine degenerative changes, following natural aging, the declines of population group means of spine BMD and T-score are faster for Chinese women than for Caucasian women. While a cutpoint T-score ≤ -2.5 for defining spine densitometric osteoporosis is recommended for Caucasian women, for Chinese women the same cutpoint T-score of ≤ -2.5 inflates the estimated osteoporosis prevalence based on spine BMD measure. In addition to the use of an ethnicity-specific BMD reference database, a stricter cutpoint T-score for defining spine densitometric osteoporosis among older Chinese women should be applied., (© 2023. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Osteoporosis will become even more prevalent as the world population ages. Radiologists are well placed to recognize this disease that often first manifests on routine imaging studies. Most radiologists encounter patients with osteoporosis during their normal daily reporting. Osteoporosis is prone to potential pitfalls on imaging, and the more common of these are outlined in this review., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Context: Measurement of areal bone mineral density (aBMD) by dual-energy x-ray absorptiometry (DXA) was able to predict fracture risk. High-resolution peripheral quantitative computed tomography (HR-pQCT) yields additional information about volumetric bone mineral density (vBMD), microarchitecture, and strength that may increase our understanding of fracture susceptibility., Objective: To ascertain whether vBMD, microarchitecture, and estimated bone strength derived from HR-pQCT can discriminate vertebral fractures in patients with glucocorticoid-induced osteoporosis (GIOP) independent of aBMD., Design: A cross-sectional case-control study., Setting: Seven regional hospitals in Hong Kong., Patients: A total of 110 patients on long-term glucocorticoids with vertebral fracture, determined radiographically, and 110 patients on long-term glucocorticoids without fracture., Main Outcome Measures: We assessed vBMD, microarchitecture, and bone strength; aBMD; and fracture risk assessment tool (FRAX)., Results: Patients with vertebral fracture had lower total vBMD and a thinner cortex at the distal tibia after adjustment for age, sex, and aBMD or FRAX. In the antiresorptive treatment-naive subgroup, patients with vertebral fracture also had lower total vBMD at both the distal radius and the tibia after adjustment for covariates. Lower total vBMD and a thinner cortex were also noticed in the nonosteoporotic or FRAX score of <10% subgroups with vertebral fracture and were also associated with increasing prevalence of vertebral fracture., Conclusion: Patients with GIOP and vertebral fracture have a significant reduction in total vBMD and cortical thinning independent of aBMD and FRAX. These changes may help identify high-risk patients in the subgroups currently considered to have low fracture risk as assessed by DXA or FRAX.

Unlabelled: In this study, we characterized longitudinal changes of volumetric bone mineral density and cortical and trabecular microstructure at the distal radius using HR-pQCT in female systemic lupus erythematosus (SLE) patients on long-term glucocorticoids. Cortical thinning and increased cortical porosity are the major features of longitudinal microstructural deterioration in SLE patients., Introduction: The study aims to characterize longitudinal changes of volumetric bone mineral density (vBMD) and bone microstructure at distal radius in female systemic lupus erythematosus (SLE) patients on long-term glucocorticoids., Methods: This 2-year case-control study consisted of 166 premenopausal subjects (75 SLE patients and 91 controls) and 79 postmenopausal subjects (44 SLE patients and 35 controls). We obtained areal BMD (aBMD) by dual-energy X-ray absorptiometry at multiple skeletal sites and indices of vBMD and microstructure at distal radius by high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline, 12 and 24 months., Results: In either premenopausal or postmenopausal subjects, changes in aBMD did not differ between patients and controls except that decrease in aBMD at total hip at 24 months in premenopausal patients was significantly higher. In premenopausal subjects, decrease in cortical area (-0.51 vs. -0.06 %, p = 0.039) and thickness (-0.63 vs. 0.02 %, p = 0.031) and increase in cortical porosity (21.7 vs. 7.16 %, p = 0.030) over study period were significantly larger in patients after adjustment of age and body mass index. Decreased in trabecular vBMD was significantly less (-0.63 vs. -2.32 %, p = 0.001) with trabecular microstructure better maintained in patients. In postmenopausal subjects, decrease in cortical vBMD (-2.66 vs. -1.56 %, p = 0.039) and increase in cortical porosity (41.6 vs. 16.3 %, p = 0.021) were significantly higher in patients, and there was no group-wise difference in change of trabecular microstructure., Conclusion: Longitudinal microstructural deterioration in SLE is characterized by cortical thinning and increased cortical porosity. Cortical bone is an important source of bone loss in SLE patients on glucocorticoids.

Unlabelled: We investigated the densitometric and microstructural features of the distal radius in psoriatic arthritis (PsA) patients using high-resolution peripheral quantitative computed tomography. PsA patients have unique bone microstructural deficits, manifested as lower cortical bone density and higher cortical porosity, which are associated with a propensity to bone fragility., Introduction: The aim of this study was to investigate the densitometric, geometric, microstructural, and biomechanical features of the distal radius in psoriatic arthritis (PsA) patients., Methods: This study cohort consisted of 53 PsA patients (24 males and 29 females), with an average age of 53.1 years and 53 gender- and age-matched controls. Areal bone mineral density (aBMD) of the hip, lumbar spine, and ultradistal radius was measured by dual-energy X-ray absorptiometry. High-resolution peripheral quantitative computed tomography (HR-pQCT) was performed at the distal radius to obtain measures of volumetric BMD (vBMD), microstructure, and derived biomechanical indices., Results: There were no significant between-group differences in aBMD at the femoral neck, total hip, and ultradistal radius, while aBMD at the lumbar spine was significantly higher in patients. The only indices indicating compromised bone quality in PsA patients were related to cortical bone quality. Cortical vBMD were -3.8% significantly lower, while cortical pore volume, porosity index, and pore diameter were 108, 79.5, and 8.6%, respectively, significantly higher in patients. Cortical stress was marginally lower (-1.3%, p = 0.077) in patients with stress significantly more unevenly distributed (4.9%, p = 0.035). Endocortical perimeter and cortical pore volume were significantly higher in patients with vertebral fracture. Deficits in cortical bone quality were associated with indices of disease activity/severity and were more prominent in patients with type 2 diabetes mellitus or hypertension., Conclusions: There is an intertwined relationship between chronic inflammation, cardiovascular risk factors, and bone loss in PsA. PsA patients seem to have unique bone microstructural deficits which are associated with a propensity to bone fragility.

Bone marrow was assumed to be negligible on the aspect of bone mechanical behavior, where bone mass and bone mineral density were most studied. As a result, if the bone marrow, especially the marrow fat, plays a role in the bone mechanical properties is unknown yet. Marrow fat content was found increased in osteoporotic bone. However, the relationship between such change of bone marrow and bone strength is not clear yet. This study was proposed to investigate the effect of marrow fat on the bone biomechanical performance by computer simulations. A finite element model was established based on trabecular structure extracted from quantitative CT at L3 vertebrae. Simulations were conducted on the models with and without marrow fat under the same condition, respectively. The results showed that the cancellous bone with marrow fat had a 7.56%~18.81% higher maximum stress in trabeculae. Further, trabeculae with higher Young's modulus tend to sustain a higher maximum compressive stress when considering the marrow fat. As a conclusion, the marrow fat has effect on bone biomechanics, which cannot be ignored. Such effect in osteoporosis should be further investigated in deep.

Objective: Osteoporotic Fractures in Men (Hong Kong) and Osteoporotic Fractures in Women (Hong Kong) represent the first large-scale prospective population-based studies on bone health in elderly (age≥65 years) Chinese men (n=2,000) and women (n=2,000). We undertook the current study to investigate the prevalence of lumbar disc space narrowing in these subjects, and to identify the potential relationship between disc space narrowing and sex, bone mineral density (BMD), and other demographic and clinical data., Methods: On lumbar lateral radiographs, L1/L2-L4/L5 disc space was classified into 4 categories: 0=normal; 1=mild narrowing; 2=moderate narrowing; 3=severe narrowing. We compared demographic and clinical data between subjects with and those without total disc space narrowing scores≥3., Results: Disc space narrowing was more common in elderly women than in elderly men. The mean±SD disc space narrowing score for the 4 discs was 2.71±2.21 for men and 3.08±2.50 for women (P<0.0001). For the 3 age groups of 65-69 years, 70-79 years, and ≥80 years, the average disc space narrowing score increased with increasing age in both men and women, and to a greater degree in women than in men. The average disc space narrowing score differences between women and men were 0.12, 0.40, and 0.90, respectively, in the 3 age groups. For both men and women, a disc space narrowing score≥3 was associated with older age, higher spine and hip BMD, low back pain, and restricted leg mobility., Conclusion: The prevalence and severity of disc space narrowing are higher in elderly women than in elderly men. With increasing age, disc space narrowing progresses at a greater rate in women than in men. A disc space narrowing score≥3 is associated with higher spine and hip BMD., (Copyright © 2013 by the American College of Rheumatology.)

Study Design: Cross-sectional study., Objective: To investigate changes in the morphology of the lumbar vertebrae and intervertebral discs associated with osteoporosis of the spine in elderly subjects., Summary of Background Data: Osteoporosis is a common condition that primarily affects the elderly with significant impact on quality of life. How exactly osteopenia and osteoporosis influence vertebral and intervertebral disc morphology remains unknown and needs exploration., Methods: A total of 395 community-dwelling ambulatory adults from 67 to 89 years of age were studied. The lumbar bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry. T2-weighted sagittal images of the lumbar spine were obtained using a 1.5-T magnet. For each subject, the anterior height (Ha), middle height (Hm), posterior height (Hp), and anterior-posterior (AP) dimension of the 5 lumbar vertebrae (L1-L5) and 6 intervertebral discs (T12-L1 to L5-S1) were measured. To minimize the age effect, volume of these vertebrae and discs was measured in subgroups of 47 men (mean age = 74 yr, range: 73-75 yr) and 67 women (mean age = 72 yr, range: 71-73 yr). Continuous variables were examined by analysis of covariance after adjustment of height and age., Results: There was no significant age difference between the groups of normal BMD, osteopenia, and osteoporosis. For the vertebral bodies, lower BMD was associated with a decrease of Ha, Hm, and Hp but not AP in both sexes, leading to an increased biconcavity index. For the discs, lower BMD was associated with a decrease of Ha and Hp, as well as AP, and an increase in Hm in both men and women. The disc biconvexity index was increased. Lower BMD is associated with an overall decrease in both vertebral volume and disc volume., Conclusion: Lower BMD is associated with a decreasing trend in both lumbar vertebral and disc volumes in elderly subjects but an increase in the Hm of the intervertebral discs.

Stained histological images assist physicians to identify different types of tissues or cells and their architectures. They can be applied on the diagnosis of various diseases and the assessment of treatment effects. Osteoporosis is an aging disease that reduces the density of bones and increases the risk of bone fracture. Literatures indicate that osteoporosis is associated with the ratio of trabecular bone tissues and bone marrow cells, and bones in osteoporosis patients consist of a significantly higher marrow fat content. Interactive segmentation of bone tissue and different types of bone marrow cells in high-resolution histological images, however, is a very tedious and labor-intensive process. The aim of this study is to develop an automatic algorithm to quantify the areas of different tissues such as the trabecular bones and yellow and red marrow cells. This image segmentation method consists of a series of mathematical morphological operation steps based on both the color and morphology features of tissues and was implemented in Matlab. The results obtained from the proposed method have been verified by comparing with those obtained interactively from an experienced histotechnician (Pearson correlation coefficient > 0.94, P < 0.001). The result suggests that the proposed algorithm can effectively assist physicians to quantify stained bone histological images., (Copyright © 2012 International Society for Advancement of Cytometry.)

Tremendous advances have been made over the past several decades in assessing osteoporosis and its complications. High resolution imaging combined with sophisticated computational techniques now provide a detailed analysis of bone structure and a much more accurate prediction of bone strength. These techniques have shown how different mechanisms of age-related bone weakening exist in males and females. Limitations peculiar to these more advanced imaging techniques currently hinder their adoption into mainstream clinical practice. As such, the ultimate quest remains a readily available, safe, high resolution technique capable of fully predicting bone strength, capable of showing how bone strength is faltering and precisely monitoring treatment effect. Whether this technique will be based on acquisition of spine/hip data or data obtained at peripheral sites reflective of changes happening in the spine and hip regions is still not clear. In the meantime, mainstream imaging will continue to improve the detection of osteoporosis related insufficiency fracture in the clinical setting. We, as clinicians, should aim to increase awareness of this fracture type both as a frequent and varied source of pain in patients with osteoporosis and as the ultimate marker of severely impaired bone strength.

A reduced bone perfusion has been found for osteoporotic subjects in previous studies. However, the physiological changes underlying the varied perfusion function is not well known yet. Tofts model is one of the most frequently used pharmacokinetic models in analyzing perfusion process. This study modified the Tofts model by replacing the arterial input function (AIF) by a new algorithm. The modified model was then employed to analyze vertebral bone marrow perfusion in subjects with different bone mineral density (BMD). Eighty-two male subjects were involved in this study and classified into three groups (normal, osteopenia, and osteoporosis) according to T-score. BMD was measured by dual-energy X-ray absorptiometry (DXA). The quantitative parameters derived from the pharmacokinetic model, K(trans) (extravasation transfer efficiency for blood perfusion) and v(e) (extravascular extracellular space for blood perfusion), showed a significant reduction in subjects with lower BMD, respectively. The results suggested that with the bone mineral content lost, the vascular wall properties as well as the bone marrow content may also vary. The resultant perfusion change may also influence the bone nutrition supply in reverse.

The digital era has witnessed an exponential growth in bone imaging as new modalities and analytic techniques improve the potential for noninvasive study of bone anatomy, physiology, and pathophysiology. Bone imaging very much lends itself to input across medical and engineering disciplines. It is in part a reflection of this multidisciplinary input that developments in the field of bone imaging over the past 30 years have in some respects outshone those in many other fields of medicine. These developments have resulted in much deeper knowledge of bone macrostructure and microstructure in osteoporosis and a much better understanding of the subtle changes that occur with age, concurrent disease, and treatment. This new knowledge is already being translated into improved day-to day clinical care with better recognition, treatment, and monitoring of the osteoporotic process. As "the more you know, the more you know you don't know" certainly holds true with osteoporosis and bone disease, there is little doubt that further advances in bone imaging and analytical techniques will continue to hold center stage in osteoporosis and related research.

Purpose: To apply pharmacokinetic modeling to the investigation of bone perfusion in subjects of varying bone mineral density., Materials and Methods: This study re-analyzed previous experimental data. A modified pharmacokinetic model was applied to data obtained from two prior studies of dynamic contrast-enhanced MR imaging of L3 vertebral body in 165 subjects (65 males, 100 females), classified into three groups (normal, osteopenia, and osteoporosis) according to bone mineral density. Three parameters, amplitude A, exchange rate (k(ep)), and elimination rate (k(el)), were obtained by fitting the signal intensity to the pharmacokinetic model. These parameters were compared across the three groups for males and females, respectively., Results: Perfusion parameters, amplitude A was found to be reduced in osteoporotic subjects with additional, though less pronounced, reductions found in the permeability constant (A*k(ep)) and the elimination rate (k(el)). Increased marrow fat content was found in osteoporotic bone, which helped to partially explain the observed reduction in interstitial space., Conclusion: By pharmacokinetic model, bone perfusion can be quantitatively analyzed with alteration in functional parameters related to microcirculation in subjects of varying bone mineral density. Developing bone marrow specific pharmacokinetic models should help to deepen knowledge of physiological and pathological perfusion changes occurring in bone., (Copyright 2010 Wiley-Liss, Inc.)

Vertebral fractures are usually the first to occur in osteoporosis, provide indisputable evidence of reduced bone strength, and are frequently a harbinger of further vertebral and nonvertebral fracture. Radiologists are best placed to draw attention to the presence of vertebral fractures, most of which are clinically silent. Magnetic resonance imaging supplemented if necessary by computed tomography is usually sufficient to enable distinction between osteoporotic and non-osteoporotic vertebral fracture, without a need for percutaneous biopsy., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

Purpose: To investigate the cause of reduced vertebral perfusion in a rat ovariectomy model., Materials and Methods: Experimental protocol was approved by the local Animal Experiment Ethics Committee. Twenty-two Sprague-Dawley rats were studied. Computed tomographic bone densitometry and magnetic resonance perfusion imaging were performed at baseline and 2, 4, and 8 weeks after ovariectomy (n = 11) or sham surgery (n = 11). Perfusion parameters analyzed were maximum enhancement (E(max)) and enhancement slope (E(slope)). After the animals were sacrificed, the aorta and femoral artery were analyzed for vessel reactivity, and the lumbar vertebrae were analyzed for marrow content., Results: In control rats, bone mineral density (BMD), E(max), and E(slope) remained constant. In ovariectomy rats, a comparable reduction in BMD and the perfusion parameters at two weeks post-ovariectomy (BMD, 9.3%; E(max), 11.6%; E(slope), 9%) was seen 2 weeks after ovariectomy, and further reductions were seen 4 weeks (BMD, 17.5%; E(max), 15.6%; E(slope), 33%) and 8 weeks (BMD, 18.8%; E(max), 14.2%; E(slope), 33%) after ovariectomy. Endothelial dysfunction was observed in both the aorta and femoral artery of the ovariectomy group but not of the control group. Increased marrow fat area was seen in the ovariectomy group (52.9% vs 21.6%; P < .01) owing to an increase in fat cell number. Decreased erythropoetic marrow area (32.5% vs 48.6%; P < .05) was also observed in the ovariectomy group., Conclusion: Reduced bone perfusion occurs in synchrony with reduced BMD. The most likely causes of reduced bone perfusion are a reduction in the amount of erythropoetic marrow and endothelial dysfunction after ovariectomy., Supplemental Material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09090608/-/DC1., ((c) RSNA, 2010)

Objective: To investigate the prevalence of vertebral fractures and to identify risk factors associated with vertebral fractures in Chinese women with systemic lupus erythematosus (SLE)., Methods: One hundred fifty-two consecutive patients with SLE were recruited in this cross-sectional study. Bone mineral density (BMD) measurements of the hip and spine were performed using the same dual energy X-ray absorptiometry (DEXA). Lateral radiographs of the spine (T5-L4) were assessed for vertebral fractures using a method described by Genant. Inflammatory and biochemical markers included C-reactive protein, receptor activator of nuclear factor-kappaB ligand, serum ss-CrossLaps assay for C-terminal telopeptides of type 1 collagen, and osteoprotegerin (OPG)., Results: Asymptomatic vertebral fractures occurred in 20.4% of patients with SLE. Univariate analyses of variables associated with fractures were older age, higher body mass index (BMI), lower BMD spine, lower BMD hips, higher serum C3 and C4, longer estrogen exposure, higher levels of OPG, and the use of sunscreen. Multivariate analysis showed older age (p = 0.017), higher BMI (p < 0.036), and lower BMD of the spine were significantly associated with vertebral fractures in the thoracic and/or lumbar spine (odds ratio 1.068, 1.166, 0.005; p = 0.018, p = 0.025, p = 0.003, respectively)., Conclusion: Asymptomatic vertebral fractures occur in 20.4% of patients with SLE and 30% of these patients have normal BMD. The current method using DEXA to predict the presence of vertebral fracture has limited value and there is a need for assessment of bone quality. Vertebral morphometry in patients with SLE is recommended and early therapeutic intervention is necessary to prevent vertebral fractures in patients with SLE.

Lumbar spine kinematics was studied in subjects with normal bone mineral density, osteopenia and osteoporosis to determine the effect of bone mineral density and morphology on the flexion-extension movement patterns of the lumbar spine. Lateral radiographs and skin-mounted electromagnetic motion tracking sensors were employed to study lumbar spine kinematics using a Bayesian Belief Network model. The predicted angular displacement of the vertebrae had a high correlation (r = 0.91, p < 0.001) with the actual movements. The overall mean error was -0.51 degrees +/- 3.11 degrees. Intervertebral angular displacement and velocity consistently increased from L1/L2 to L5/S1. Differences were observed in the movement pattern between normal subjects and those with decreased bone density. In normal subjects, vertebral angular acceleration consistently decreased from the upper to the lower vertebrae but the same consistent predictable pattern was not observed in the subjects with decreased bone mineral density. It is possible that these changes in kinematic behaviours are related to morphological changes as well as altered neuromuscular functions.

Study Design: Cross-sectional study., Objective: The purpose of this study was to examine disc morphology and spinal mobility in subjects with varying degrees of osteoporosis., Summary of Background Data: There was limited information on the effect of osteoporosis on lumbar morphology and spinal mobility. It was also unclear how osteoporosis affects the nonosseous tissues such as the intervertebral disc., Methods: Ninety elderly subjects with varying bone mineral densities (22 normal, 28 osteopenia, 40 osteoporosis) were recruited from an osteoporosis clinic. Lateral radiographs and magnetic resonance images of their lumbar spines were obtained. An electromagnetic tracking device was employed to measure the ranges of motion of the whole lumbar spine., Results: Although the thoracic spine had been shown to have decreased anterior vertebral body height in subjects with osteoporosis, this study revealed that the anterior height was increased in the lumbar region. Osteoporosis was associated with expansion of the middle of the disc with corresponding collapse of vertebral bodies, but osteoporosis was found not to be related to either disc preservation or degeneration. No significant change in spinal mobility was observed in patients with osteoporosis., Conclusion: Osteoporosis does not only affect the bone but also the nonosseous tissues. It was found to be associated with expansion of the intervertebral disc, which was likely to be secondary to changes in the vertebral endplate.

Bone fracture occurs when the bone strength (i.e. the ability of the bone to resist a force) is less than the force applied to the bone. In the elderly, falls represent the more severe forces applied to bone. Bone density is a good marker of bone strength, and has been used widely in this respect. Nevertheless, many aspects of bone strength cannot be explained by bone density alone. For this reason there has been increasing interest in studying architectural parameters of bone, beyond bone density, which may affect bone strength. Macro-architectural parameters include e.g. bone size and geometry assessed with techniques such as radiography, dual-energy x-ray absorptiometry (DXA), peripheral quantitative computed tomography (QCT), computed tomography (CT) and magnetic resonance imaging (MRI). Micro-architectural parameters include fine cortical and trabecular structural detail which can be evaluated using high-resolution imaging techniques such as multidetector CT, MRI, and high-resolution peripheral QCT. These techniques are providing a great deal of new information on the physiological architectural responses of bone to aging, weightlessness, and treatment. This will ultimately lead to the prediction of fracture risk being improved through a combined assessment of bone density and architectural parameters.

A link between bone blood flow and osteoporosis may exist. Outside of the spine, the proximal femur is the most common site of osteoporotic fracture and is also an area prone to avascular necrosis and fracture nonunion. This study of the proximal femur investigates the relationship between BMD, bone marrow fat content, bone perfusion, and muscle perfusion. One hundred twenty healthy female subjects (mean age, 74 yr; age range, 67-89 yr) underwent DXA examination of the hip, proton MR spectroscopy, and dynamic contrast-enhanced MR imaging of the right proximal femur, acetabulum, and adductor thigh muscle. In all bone areas examined (femoral head, femoral neck, femoral shaft, acetabulum), perfusion indices (maximum enhancement, enhancement slope) were significantly reduced in subjects with osteoporosis compared with subjects with osteopenia or normal BMD. Adductor muscle perfusion was not affected by change in BMD. As marrow perfusion decreased in the proximal femur, marrow fat increased (r = 0.827). This increase in fat content seemed to account for the decrease in marrow perfusion more than a reduction in BMD. For normal BMD subjects, perfusion parameters in the femoral head were one third of those in the femoral neck or shaft and one fifth of those in the acetabulum. Perfusion throughout the proximal femur is reduced in osteoporotic subjects compared with osteopenic and normal subjects. This reduction in perfusion only affects bone and not those tissues outside of bone with the same blood supply. As bone perfusion decreased, there was a corresponding increase in marrow fat.

Correlation between kinematics and morphological characteristics of lumbar spine was studied in subjects with varying bone mineral density. Effect of morphological characteristics and bone mineral density on the lumbar spine movement was investigated. Morphology parameters were measured from radiographs and a high-frequency motion tracking device were employed to detect surface movement of lumbar spine. Multiple regression analysis identified factors influencing lumbar kinematics while ANOVA examined differences in morphology with normal bone mineral density, osteopenia and osteoporosis. The results show that morphological characteristics, such as wedging deformity, are indeed influential to the kinematics. Related to our previous report, abnormal lumbar kinematic pattern in the subjects with osteoporosis, this study shows although morphological characteristics were found significantly different among normal, osteopenia, and osteoporosis subjects, the change in lumbar kinematic pattern could not be fully explained by the altered vertebral or disc morphology.

Purpose: To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material-enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA)., Materials and Methods: This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67-101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes., Results: Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73 years; range, 67-101 years) that included 42 subjects with normal bone density (mean T score, 0.8 +/- 1.1 [standard deviation]), 23 subjects with osteopenia (mean T score, -1.6 +/- 0.4), and 17 subjects with osteoporosis (mean T score, -3.2 +/- 0.5). Vertebral marrow fat content was significantly increased in subjects with osteoporosis (mean fat content, 58.23% +/- 7.8) (P = .002) or osteopenia (mean fat content, 55.68% +/- 10.2) (P = .034) compared with that in subjects with normal bone density (50.45% +/- 8.7). Vertebral marrow perfusion indexes were significantly decreased in osteoporotic subjects (mean enhancement slope, 0.78%/sec +/- 0.3) compared with those in osteopenic subjects (mean enhancement slope, 1.15%/sec +/- 0.6) (P = .007) and those in subjects with normal bone density (mean enhancement slope, 1.48%/sec +/- 0.7) (P < .001)., Conclusion: Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia. Similarly, subjects with osteopenia have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with normal bone density.

Osteoporosis is associated with thinning of cortical and trabecular bone, which reduces bone strength and predisposes individuals to fracture development. Femoral neck fractures in patients with osteoporosis may not be apparent on radiographs. Magnetic resonance imaging is useful at detecting these radiographically occult fractures; yet, the practice has not been widely adopted in Hong Kong. In this article, we review our experience of early magnetic resonance imaging in this clinical context--that is, imaging performed within 48 hours of presentation to hospital. Twenty-eight patients (age range, 69-93 years) over a 3-year period were studied. Magnetic resonance imaging revealed radiographically occult neck fractures in 14 (50%) cases (equivalent to 4% of all femoral neck fractures). These fractures were treated surgically (64%) or conservatively (36%) with good bone healing and clinical outcome. When no femoral neck fracture was present, magnetic resonance imaging revealed an alternative cause for symptoms in all 14 cases. We strongly endorse the use of early magnetic resonance imaging for patients with osteoporosis who have a clinically suspected femoral neck fracture that is not visible radiographically.

Purpose: To determine the diffusion of vertebral body marrow with quantitative MR diffusion imaging and to examine whether differences exist between subjects with postmenopausal osteoporosis and premenopausal control subjects., Materials and Methods: A total of 44 consecutive women (mean age, 70 years) with documented bone mineral density (BMD) measured by dual energy x-ray absorptiometry (T-score) and 20 normal subjects (mean age, 28 years) were examined with echo-planar diffusion imaging at 1.5 T using b values of 0, 20, 40, 60, 80, 100, 200, 300, 400, and 500 seconds/mm2. Extravascular diffusion (D) and apparent diffusion coefficient (ADC) were calculated and results from both groups compared., Results: Both D and ADC values tended to decrease with decreasing BMD. Mean D values were significantly lower in postmenopausal women with reduced BMD (0.42 +/- 0.12 x 10(-3) mm2/second) than normal premenopausal women (0.50 +/- 0.09 x 10(-3) mm2/second). Mean ADC values were significantly lower both in subjects with reduced BMD (0.41 +/- 0.10 x 10(-3) mm2/second) and normal BMD (0.43 +/- 0.08 x 10(-3) mm2/second) compared to normal controls (0.49 +/- 0.07 x 10(-3) mm2/second)., Conclusion: Accumulation of fatty bone marrow associated with osteoporosis is reflected by a decrease in D and ADC. Diffusion imaging may prove useful in the study of osteoporosis., (Copyright 2004 Wiley-Liss, Inc.)

Objective: In recurrent anterior shoulder dislocation, glenoid bone loss may predispose the patient to further dislocation and failure of a Bankart repair. This study investigates the quantification of glenoid bone loss in anterior shoulder dislocation using CT., Subjects and Methods: CT examinations were performed on 40 patients (average age, 31 years; range, 13-82 years), comprising 46 shoulders with anterior dislocation and 34 contralateral normal shoulders. Twenty shoulders in 10 healthy subjects were also examined. Both shoulders were examined simultaneously. Image reconstruction included oblique sagittal reformatted images en face to the glenoid fossa. Seven aspects of glenoid fossa shape and size were measured, including the cross-sectional area, maximum width, maximum height, and flattening of the anterior glenoid curvature., Results: Variable flattening of the anterior glenoid curvature was a feature in 42 (91%) of 46 dislocated shoulders although it was seen in only two (4%) of 54 normal shoulders. Anterior glenoid flattening increased exponentially with an increasing number of dislocations. Anterior glenoid flattening, decreased maximum glenoid width, and decreased maximum width-to-length ratio were the most useful measures of bone loss. Maximum glenoid width was smaller than on the contralateral side in 79% of patients with unilateral dislocation by an average of 3.0 mm (range, 0.1-10 mm) or 10.8% (range, 0.4-32%). Glenoid cross-sectional area was a less useful measure of glenoid bone loss., Conclusion: Flattening of the anterior glenoid curvature is shown in most patients with anterior dislocation. In unilateral dislocation, a comparison of maximum glenoid width with that on the contralateral side was the best discriminator of moderate to severe glenoid bone loss.

The article presents a study which investigates the risk factors and incidence of non-vertebral and vertebral fracture in female Chinese patients with systemic lupus erythematosus (SLE). Topics discussed include the measurement of bone mineral density (BMD), the prevalence of osteoporosis, and the use of dual-energy X-ray absorptiometry.