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Introduction Impaired bone microarchitecture is involved in vertebral fracture (VF) development among acromegaly patients. Aim of the study Comparison of DXA-derived bone parameters, areal BMD (aBMD), trabecular bone score (TBS) and 3D-SHAPER parameters in acromegaly patients with healthy controls. Methods This cross-sectional study evaluated acromegaly patients and a control group of healthy subjects. In all subjects, a single measurement of pituitary axis hormone levels, bone turnover markers, aBMD, (total hip (TH) and lumbar spine (LS)), TBS and 3D-SHAPER of the proximal femur region was performed. All subjects underwent DXA assessment of VF using the semiquantitative approach. Results One hundred six patients with acromegaly (mean age 56.6 years, BMI 30.2 kg/m2) and 104 control subjects (mean age 54.06 years, 28.4 BMI kg/m2) were included. After adjustment for weight, LS aBMD, TBS and TH trabecular volumetric BMD (vBMD) remained lower (P = 0.0048, <0.0001 and <0.0001, respectively) while cortical thickness (Cth) at TH and neck remained thicker (P = 0.006) in acromegaly patients compared with controls. The best multivariate model (model 1) discriminating patients with and without acromegaly included TBS, TH trabecular vBMD and TH Cth parameters (all P < 0.05). Twenty-two VFs (13 acromegaly subjects) were recognized. In these subjects after adjustment for age, FN aBMD, TH cortical sBMD and TH cortical vBMD remained significantly associated with the prevalent VF (OR = 2.69 (1.07-6.78), 2.84 (1.24-6.51) and 2.38 (1.11-5.10) for neck aBMD, TH cortical sBMD and TH cortical vBMD respectively)). The AUCs were similar for each parameter in this model. Conclusions Acromegaly patients, regardless of VF presence, have lower trabecular bone quantitative parameters, but those with VFs had decreased cortical density.

Romosozumab is a monoclonal antibody that inhibits sclerostin and has been shown to reduce the risk of fractures within 12 months. In a phase II, randomized, placebo-controlled clinical trial of treatment-naïve postmenopausal women with low bone mass, romosozumab increased bone mineral density (BMD) at the hip and spine by the dual effect of increasing bone formation and decreasing bone resorption. In a substudy of that trial, which included placebo and teriparatide arms, here we investigated whether those observed increases in BMD also resulted in improvements in estimated strength, as assessed by finite element analysis. Participants received blinded romosozumab s.c. (210 mg monthly) or placebo, or open-label teriparatide (20 μg daily) for 12 months. CT scans, obtained at the lumbar spine (n = 82) and proximal femur (n = 46) at baseline and month 12, were analyzed with finite element software (VirtuOst, O.N. Diagnostics) to estimate strength for a simulated compression overload for the spine (L 1 vertebral body) and a sideways fall for the proximal femur, all blinded to treatment assignment. We found that, at month 12, vertebral strength increased more for romosozumab compared with both teriparatide (27.3% versus 18.5%; p = 0.005) and placebo (27.3% versus -3.9%; p < 0.0001); changes in femoral strength for romosozumab showed similar but smaller changes, increasing more with romosozumab versus teriparatide (3.6% versus -0.7%; p = 0.027), and trending higher versus placebo (3.6% versus -0.1%; p = 0.059). Compartmental analysis revealed that the bone-strengthening effects for romosozumab were associated with positive contributions from both the cortical and trabecular bone compartments at both the lumbar spine and hip. Taken together, these findings suggest that romosozumab may offer patients with osteoporosis a new bone-forming therapeutic option that increases both vertebral and femoral strength within 12 months. © 2017 American Society for Bone and Mineral Research., (© 2017 American Society for Bone and Mineral Research.)

Genetic factors likely contribute to the risk for vertebral fractures; however, there are few studies on the genetic contributions to vertebral fracture (VFrx), vertebral volumetric bone mineral density (vBMD), and geometry. Also, the heritability (h(2)) for VFrx and its genetic correlation with phenotypes contributing to VFrx risk have not been established. This study aims to estimate the h(2) of vertebral fracture, vBMD, and cross-sectional area (CSA) derived from quantitative computed tomography (QCT) scans and to estimate the extent to which they share common genetic association in adults of European ancestry from three generations of Framingham Heart Study (FHS) families. Members of the FHS families were assessed for VFrx by lateral radiographs or QCT lateral scout views at 13 vertebral levels (T(4) to L(4)) using Genant's semiquantitative (SQ) scale (grades 0 to 3). Vertebral fracture was defined as having at least 25% reduction in height of any vertebra. We also analyzed QCT scans at the L(3) level for integral (In.BMD) and trabecular (Tb.BMD) vBMD and CSA. Heritability estimates were calculated, and bivariate genetic correlation analysis was performed, adjusting for various covariates. For VFrx, we analyzed 4099 individuals (148 VFrx cases) including 2082 women and 2017 men from three generations. Estimates of crude and multivariable-adjusted h(2) were 0.43 to 0.69 (p < 1.1 × 10(-2)). A total of 3333 individuals including 1737 men and 1596 women from two generations had VFrx status and QCT-derived vBMD and CSA information. Estimates of crude and multivariable-adjusted h(2) for vBMD and CSA ranged from 0.27 to 0.51. In a bivariate analysis, there was a moderate genetic correlation between VFrx and multivariable-adjusted In.BMD (-0.22) and Tb.BMD (-0.29). Our study suggests vertebral fracture, vertebral vBMD, and CSA in adults of European ancestry are heritable, underscoring the importance of further work to identify the specific variants underlying genetic susceptibility to vertebral fracture, bone density, and geometry., (Copyright © 2012 American Society for Bone and Mineral Research.)

Unlabelled: Two radiologists evaluated images of the spine from computed tomography (CT) scans on two occasions to diagnose vertebral fracture in 100 individuals. Agreement was fair to good for mild fractures, and agreement was good to excellent for more severe fractures. CT scout views are useful to assess vertebral fracture., Introduction: We investigated inter-reader agreement between two radiologists and intra-reader agreement between duplicate readings for each radiologist, in assessment of vertebral fracture using a semi-quantitative method from lateral scout views obtained by CT., Methods: Participants included 50 women and 50 men (age 50-87 years, mean 70 years) in the Framingham Study. T4-L4 vertebrae were assessed independently by two radiologists on two occasions using a semi-quantitative scale as normal, mild, moderate, or severe fracture., Results: Vertebra-specific prevalence of grade ≥ 1 (mild) fracture ranged from 3% to 5%. We found fair (κ = 56-59%) inter-reader agreement for grade ≥ 1 vertebral fractures and good (κ = 68-72%) inter-reader agreement for grade ≥ 2 fractures. Intra-reader agreement for grade ≥ 1 vertebral fracture was fair (κ = 55%) for one reader and excellent for another reader (κ = 77%), whereas intra-reader agreement for grade ≥ 2 vertebral fracture was excellent for both readers (κ = 76% and 98%). Thoracic vertebrae were more difficult to evaluate than the lumbar region, and agreement was lowest (inter-reader κ = 43%) for fracture at the upper (T4-T9) thoracic levels and highest (inter-reader κ = 76-78%) for the lumbar spine (L1-L4)., Conclusions: Based on a semi-quantitative method to classify vertebral fractures using CT scout views, agreement within and between readers was fair to good, with the greatest source of variation occurring for fractures of mild severity and for the upper thoracic region. Agreement was good to excellent for fractures of at least moderate severity. Lateral CT scout views can be useful in clinical research settings to assess vertebral fracture.

Unlabelled: This study evaluates baseline characteristics of 704 women and men in the Framingham Study with respect to long-term risk of incident vertebral fracture. Incidence was 24% in women and 10% in men. Few factors in middle-aged persons, except prevalent (moderate) fracture and alcohol consumption (in men), predicted long-term incidence of vertebral fracture., Introduction: We studied potential risk factors in women and men in middle adult years to help identify individuals at increased long-term risk of vertebral fracture in advanced age., Materials and Methods: Participants included Framingham cohort members who underwent radiographic examinations at baseline in 1967-1969 (mean age, 53 years) and follow-up in 1992-1993. Semiquantitative methods were used to determine incident fracture, defined as any vertebral body graded normal at baseline and at least mildly deformed (20-25% reduction or more in any vertebral height) at follow-up. Information on potential risk factors was obtained from examinations conducted at or before baseline radiography., Results: Prevalence of vertebral fracture was similar (14%) in women and men, although incidence was greater in women (24%) than men (10%). Alcohol consumption increased fracture risk in men. Multivariable-adjusted ORs increased from 1.78 in men who consumed 1-3 oz of alcohol per week in middle-age years to 4.61 in those with intakes of > or =4 oz/week (trend, P = 0.0099). Age, height, weight, grip strength, physical activity, metacarpal cortical area, and estrogen use (in women) had little or no influence on cumulative incidence of vertebral fracture. Results were similar when fracture was restricted to (at least) moderate severity; however, participants with moderate to severe fracture prevalent at baseline had five times the incidence of moderate to severe fracture during follow-up compared with those without moderately to severe prevalent fractures., Conclusions: Few factors in middle-aged persons, except prevalent fracture and alcohol consumption (in men), predict long-term incidence of vertebral fracture. The explanation underlying this finding is not readily apparent, however, risk factors for vertebral fracture may be more relevant to older individuals, with respect to short-term fracture risk, than to middle-aged adults in relation to long-term risk with aging.

Introduction: Precision error in bone mineral density (BMD) measurement can be affected by patient positioning, variations in scan analysis, automation of software, and both short- and long-term fluctuations of the densitometry equipment. Minimization and characterization of these errors is essential for reliable assessment of BMD change over time., Methods: We compared the short-term precision error of two dual-energy X-ray absorptiometry (DXA) devices: the Lunar Prodigy (GE Healthcare) and the Delphi (Hologic). Both are fan-beam DXA devices predominantly used to measure BMD of the spine and proximal femur. In this study, 87 women (mean age 61.6+/-8.9 years) were measured in duplicate, with repositioning, on both systems, at one of three clinical centers. The technologists were International Society for Clinical Densitometry (ISCD) certified and followed manufacturer-recommended procedures. All scans were acquired using 30-s scan modes. Precision error was calculated as the root-mean-square standard deviation (RMS-SD) and coefficient of variation (RMS-%CV) for the repeated measurements. Right and left femora were evaluated individually and as a combined dual femur precision. Precision error of Prodigy and Delphi measurements at each measurement region was compared using an F test to determine significance of any observed differences., Results: While precision errors for both systems were low, Prodigy precision errors were significantly lower than Delphi at L1-L4 spine (1.0% vs 1.2%), total femur (0.9% vs 1.3%), femoral neck (1.5% vs 1.9%), and dual total femur (0.6% vs 0.9%). Dual femur modes decreased precision errors by approximately 25% compared with single femur results., Conclusions: This study suggests that short-term BMD precision errors are skeletal-site and manufacturer specific. In clinical practice, precision should be considered when determining: (a) the minimum time interval between baseline and follow-up scans and (b) whether a statistically significant change in the patient's BMD has occurred.

Quantitative computed tomography (QCT) was compared to dual X-ray absorptiometry (DXA) measured in the lumbar spine of 508 European women defined as normal without fracture (NoF), or osteoporotic (OP), with either vertebral fracture (VF), or peripheral fracture (PF). The correlations between QCT and DXA BMD measurements were significantly different in normal and in osteoporotic patients, indicating that the two exams do not measure the same bone aspects. According to ROC curves results, QCT Z-scores separate OP from NoF with better sensitivity than all other measurements. A threshold to differentiate OP from NoF was chosen at Z-score = -1 for DXA-BMD and -1.5 for QCT-BMD. VF patients showed a highly significant decrease in BMD by DXA or QCT. PF patients revealed measurements lower than those of normal subjects but greater than those of VF, calling into question the idea of a diffuse osteoporosis causing nonvertebral fractures that is measurable by spinal DXA or QCT. DXA is weakly dependent upon age, and T-score or Z-score are equivalent for evaluating osteoporosis. QCT depends greatly upon age, and Z-score appears to be more efficient.

Prevalent vertebral deformities are associated with a substantially increased risk of subsequent vertebral and nonvertebral fractures. Knowledge of vertebral fracture status is an important component in the prediction of further fractures in patients with osteoporosis. This study reports a comparison of the quantitative identification of vertebral deformities on morphometric X-ray absorptiometry (MXA) scans and conventional radiographs (MRX) in 161 postmenopausal women (mean age +/- SD, 64 +/- 7.1 years) recruited from patients referred by their family doctor for bone density measurement (n = 119) and osteoporotic subjects with known vertebral deformities attending an osteoporosis clinic (n = 42). Each subject had MXA scans and MRXs of the thoracolumbar spine, to image the vertebrae from T4-L4, at a single visit. The scans and radiographs were analyzed by two trained observers using six points to quantify the shape of each vertebral body. From these points, three vertebral heights were measured: anterior, middle, and posterior. Vertebral deformities were identified using the algorithms proposed by Eastell and by McCloskey. Generally good to excellent agreement (per vertebra, kappa = 0.87-0.93; per subject, kappa = 0.81-0.91) was observed between the two algorithms used for quantitative vertebral deformity identification using MXA or MRX. More moderate agreement (per vertebra, kappa = 0.70-0.79; per subject, kappa = 0.67-0.75) was seen when comparing the same algorithm between MXA and MRX. Agreement between MXA and MRX for the McCloskey algorithm was better than for the Eastell algorithm, largely because of the lower number of false positives produced by the McCloskey methodology. Deformity identification by MXA was limited because of poor image quality, primarily in the upper thoracic spine. One in six MRX deformities were missed by MXA as they occurred in vertebrae not visualized sufficiently for analysis on the MXA scans. Deformity identification was poorer in the upper thoracic spine in analyzable vertebrae with a sensitivity of 50.0% for MXA in terms of MRX using the Eastell algorithm for the vertebral levels T4-T7, compared with 80.6% for L1-L4A. MXA proved to be more effective at identifying moderate to severe MRX deformities producing a sensitivity of 22.0% for MXA in terms of identifying MRX grade 1 deformities using the Eastell algorithm, compared with 81.6% for grade 2 deformities. Although MXA image quality is inferior to that of conventional radiographs, MXA has distinct advantages such as a substantially reduced effective dose to the patient and acquisition of a single image of the spine. MXA is a potentially useful, relatively fast, low-radiation technique to identify prevalent vertebral deformities, particularly moderate to severe deformities in the middle/lower thoracic and lumbar spine, in conjunction with morphometric radiography in some patients.

Vertebral fractures are the most common osteoporotic fracture and are associated with significant pain and disability. Prior vertebral fracture and low bone mineral density (BMD) are strong predictors of new vertebral fracture. Using data from 6082 women, ages 55-80 years, in the Fracture Intervention Trial (a randomized, placebo-controlled trial of the antiresorptive agent, alendronate), we explored the association of the number of prior vertebral fractures with the risk of new fractures and whether this association is influenced by the spinal location of fractures. The risk of future vertebral fractures increased with the number of prevalent fractures, independently of age and BMD; in the placebo group, more than half of the women with five or more fractures at baseline developed new vertebral fractures, compared to only 3.8% of women without prior vertebral fractures. The magnitude of association with an increased risk of future vertebral fractures was equal for prevalent fractures located in either the "lower" (T12-L4) (relative risk [RR] = 2.9; 95% CI = 1.9, 3.6) or "upper" (T4-10) spine (RR = 2.6; 95% CI = 1.9, 3.6). We found no evidence that the effectiveness of alendronate in reducing the risk of future vertebral fracture was attenuated in women with up to five or more prevalent fractures, or that it varied by the location of prevalent fractures. However, prevalent vertebral fractures in any location were more strongly associated with risk of new fractures in the upper (RR = 5.2; 95% CI = 3.2, 8.3) than in the lower spine (2.3; 1.6, 3.3). In addition, each 1 SD decrease in spinal BMD was associated with a 2.1 (1.7, 2.6) times greater odds of new fracture in the upper spine, compared with 1.5 (1.3, 1.8) for the lower spine. These findings suggest that, in older women, osteoporosis may be a stronger risk factor for new fractures in the upper (vs. lower) thoracolumbar spine, although we found no evidence that the location of prior fractures should influence treatment decisions. Physicians should recognize that prior vertebral fractures are a strong risk factor for future fractures, and consider treating such patients to reduce their risk of subsequent fractures.

Purpose: The purpose of this work was to determine the precision and diagnostic efficacy of bone mineral density (BMD) measures based on volumetric quantitative CT (QCT) of the spine., Method: Volumetric CT scans of L1 and L2 (GE-9800Q; 80 kVp, 140 mAs, 3 mm slices) were acquired in a cohort of 62 osteoporotic women (mean age 70.4 years, T(DXA hip or spine) < -2.5), of whom 20 had vertebral fractures and 42 were nonfractured control subjects. An image analysis technique delineated trabecular, cortical, and integral regions in reference to a vertebra-fixed coordinate system. We computed precision values and fracture control differences for these new regions and for single-slice QCT and dual X-ray absorptiometry (DXA) measures synthesized from the volumetric data., Results: Volumetric trabecular BMD showed higher precision (1.3%) than the synthesized single-slice measures (2.1-2.8%). Volumetric and single-slice trabecular BMD showed equivalent decrements between fractured and nonfractured subjects (17-19%), with integral BMD showing smaller and less significant differences (7-8%)., Conclusion: Volumetric and single-slice QCT techniques are equivalent for vertebral fracture risk estimation, but volumetric techniques should be superior for monitoring therapy efficacy.

Purpose: To determine the discriminatory capability for hip fracture of trabecular and integral bone mineral density (BMD) measured with quantitative computed tomography (CT) of the spine., Materials and Methods: Fifty-six women who had sustained hip fractures and 59 control subjects underwent volumetric quantitative CT of L1 and L2 and dual x-ray absorptiometry of the hip. BMD was measured in vertebral regions of interest that encompassed trabecular, cortical, and integral bone. Logistic regression analysis was applied to each BMD measure to derive age-, weight-, and height-adjusted relative risk (RR) factors for overall hip fracture and for trochanteric fracture and cervical fracture separately., Results: Spinal trabecular BMD was modestly related to overall hip fracture (RR, 1.4-1.7; P < .05) and strongly associated with trochanteric fracture (RR, 4.2-4.5; P < .005). Spinal integral BMD related similarly to overall hip fracture (RR, 1.7-1.8; P < .05) but more weakly to trochanteric fracture (RR, 2.3-3.2; P < .01). No spinal BMD measures were significantly related to cervical fracture. BMD at the hip was strongly related to overall hip fracture (RR, 3.3-4.3; P < .001), cervical fracture (RR, 2.7-5.3; P < .001), and trochanteric fracture (RR, 2.9-7.2; P < .001)., Conclusion: Spinal trabecular BMD is strongly associated with both trochanteric and vertebral fractures.

Although the efficacy of various measures for the assessment of trabecular bone architecture has been widely studied, the impact of spatial resolution on the estimation of these measures has remained relatively unexplored. In this study, ten cubes each of human trabecular bone from the femur and vertebral bodies were obtained from nine cadavers (four males and five females), aged 23-67 years (mean 42.3 years). These specimens were serially milled and imaged at a resolution of 40 microm to produce three-dimensional digitizations from which traditional morphometric and structural anisotropy measures could be computed based on a three-dimensional approach. The cubes were then artificially degraded to an in-plane resolution of 100 microm and an out-of-plane (slice) resolution of 100-1000 microm. These resolutions mimicked in vivo resolutions as seen using magnetic resonance (MR) imaging. All images, original and degraded, were individually segmented using a thresholding algorithm, and both the traditional morphometric and structural anisotropy measures were recomputed. The choice of slice direction was varied along the superior-inferior (axial), anterior-posterior (coronal), and medial-lateral (sagittal) directions to minimize the impact of the lower slice resolution on the architectural measures. It was found that traditional morphometric measures such as trabecular spacing and trabecular number showed weak resolution dependency; measures such as trabecular thickness, however, showed strong resolution dependency and required very high resolutions for precise measurement. In the case of the femur specimens, both structural anisotropy as well as the preferred orientation showed a strong resolution dependency. The resolution dependency of these parameters could be minimized for the femur and the vertebral body specimens if the slice direction was taken along the superior-inferior direction.

Prostaglandins have been reported to mediate the effects of ovariectomy on bone loss. We studied the effect of naproxen, an inhibitor of production of prostaglandins, on ovariectomy-induced bone loss. One hundred forty female Wistar rats 4.5 months of age were divided into groups of baseline, sham operation (sham), sham treated with naproxen at 10 mg/kg per day (in food), and ovariectomy treated with naproxen or estrogen as intramuscular injection of estradiol at 0.2 mg/kg body weight per week. They were killed 3, 6, and 9 months postsurgery. Bone mineral density (BMD) of the lumbar spine (L1-4), femoral neck, midshaft, and distal metaphysis was determined using dual-energy X-ray absorptiometry (DXA) in vitro. The compressive test of the L1 vertebral body and torsional test of the left femur were performed. The right femoral neck and femoral midshaft were processed undecalcified for determining cross-sectional moments of inertia. Naproxen treatment partially prevented ovariectomy-induced loss or less gain in BMD, in a significant manner, in the femoral neck cortical area, and also in L1 compressive strength and stiffness. Estrogen fully prevented these ovariectomy-induced effects. Naproxen showed no effect on ovariectomy-induced improvement in femoral torsional strength and stiffness and cross-sectional moments of inertia. No statistically significant difference was found between naproxen-treated sham rats and untreated sham rats. The data suggest that naproxen partially prevents ovariectomy-induced osteopenia.

The purpose of this study was to use high-resolution magnetic resonance (MR) imaging combined with image analysis to investigate the three-dimensional (3D) trabecular structure, anisotropy, and connectivity of human vertebral, femoral, and calcaneal specimens. The goal was to determine whether: (a) MR-derived measures depict known skeletal-site-specific differences in architecture and orientation of trabeculae; (b) 3D architectural parameters combined with bone mineral density (BMD) improve the prediction of the elastic modulus using a fabric tensor formulation; (c) MR-derived 3D architectural parameters combined with BMD improve the prediction of strength using a multiple regression model, and whether these results corresponded to the results obtained using higher resolution depictions of trabecular architecture. A total of 94 specimens (12 x 12 x 12 mm cubes) consisting of trabecular bone only were obtained, of which there were 7 from the calcaneus, 15 from distal femur, 47 from the proximal femur, and 25 from the vertebral bodies. MR images were obtained using a 1.5 Tesla MR scanner at a spatial resolution of 117 x 117 x 300 microm. Additionally, BMD was determined using quantitative computed tomography (QCT), and the specimens were nondestructively tested and the elastic modulus (YM) was measured along three orthogonal axes corresponding to the anatomic superior-inferior (axial), medial-lateral (sagittal), and anterior-posterior (coronal) directions. A subset of the specimens (n=67) was then destructively tested in the superior-inferior (axial) direction to measure the ultimate compressive strength. The MR images were segmented into bone and marrow phases and then analyzed in 3D. Ellipsoids were fitted to the mean intercept lengths, using single value decomposition and the primary orientation of the trabeculae and used to calculate the anisotropy of trabecular architecture. Stereological measures were derived using a previously developed model and measures such as mean trabecular width, spacing, and number were derived. Because the spatial resolution of MR images is comparable to trabecular bone dimensions, these measures may be subject to partial volume effects and were thus treated as apparent measures, such as BV/TV, Tb.Sp, Tb.N, and Tb.Th rather than absolute measures, as would be derived from histomorphometry. In addition, in a subset of specimens, the Euler number per unit volume was determined to characterize the connectivity of the trabecular network. There were significant differences in the BMD, trabecular architectural measures, elastic modulus, and strength at the different skeletal sites. The primary orientation axes for most of the specimens was the anatomic superior-inferior (axial) direction. Using the fabric tensor formulation, in addition to BMD, improved the prediction of YM (SI), while including some of the architectural parameters significantly improved the prediction of strength. In comparing MR-derived 3D measures with those obtained from 20 microm optical images (n=18; 9 vertebrae, 9 femur specimens), good correlations were found for the apparent Tb.Sp and Tb.N, moderate correlation was seen for the apparent BV/TV, and poor correlation was found for the apparent Tb.Th. Using these higher resolution images, the fabric tensor formulation for predicting the elastic modulus also showed improved correlation between the measured and calculated modulus in the axial (SI) direction. In summary, high-resolution MR images may be used to assess 3D architecture of trabecular bone, and the inclusion of some of the 3D architectural measures provides an improved assessment of biomechanical properties. Further studies are clearly warranted to establish the role of architecture in predicting overall bone quality, and the role of trabecular architecture measures in clinical practice. (ABSTRACT TRUNCATED)

Purpose: Our goal was to use high resolution (HR) CT images combined with texture analysis to investigate the trabecular structure of human vertebral specimens and to compare these techniques with bone mineral density (BMD) in the prediction of bone strength., Method: HR CT images with a slice thickness of 1 mm were obtained of 28 bone cubes. Four different groups of texture analysis techniques were used to assess these images. In addition, quantitative CT (QCT) was performed and elastic modulus (EM) was determined biomechanically., Results: R2 between EM and BMD was 0.78 (p < 0.01). R2 values for EM versus most of the texture measures were also significant. Texture measures in addition to measures of BMD in a multivariate regression model significantly increased R2 up to 0.87., Conclusion: In an experimental setting, texture parameters calculated using HR CT images correlated significantly with EM. Combining texture measures with BMD improved the prediction of EM significantly.

The objective was to determine the diagnostic sensitivity of spinal and femoral dual x-ray absorptiometry (DXA) and to study whether a combination of both sites may enhance discriminatory capability in regard to the presence of vertebral fractures. Spinal and femoral DXA were obtained in 324 postmenopausal women, of whom 90 had at least one vertebral fracture. Age-adjusted logistic regression analyses, ROC analyses, and sensitivity-specificity statistics were used to assess the discriminatory ability of spinal and femoral bone density (BMD) alone and in combination. The age-adjusted odds ratios per standard deviation decrease in BMD (OR) for spinal and femoral measurements were comparable (Ward's triangle: OR = 1.62; femoral neck: OR = 1.51; total hip: OR = 1.47; spine: OR = 1.34). Combining spinal and femoral bone density measurements did not improve diagnostic sensitivity of DXA considerably as compared to using BMD of a single site and adjusting the "fracture threshold." The conclusion drawn is that spinal and femoral BMD measurements using DXA have a comparable diagnostic sensitivity for vertebral fracture discrimination. Different individuals at risk for osteoporosis may be identified using both methods. The clinical usefulness of a combination of two bone density measurements needs further study in a prospective setting.

Purpose: To evaluate radiographic absorptiometry (RA) of the phalanges in healthy women and in women with osteoporosis and to compare the results of RA with those of dual x-ray absorptiometry (DXA) of the radius and spine., Materials and Methods: Thirty-two healthy premenopausal women, 39 healthy postmenopausal women, and 35 postmenopausal women with osteoporosis underwent RA of the phalanges and DXA of the radius and lumbar spine. Pairwise comparisons, age-related bone losses, and percentage decrements and Student t values for intergroup discrimination were calculated. The ability to identify patients with osteoporotic fractures was evaluated by using receiver operating characteristic and age-adjusted logistic regression analyses. The diagnostic agreement for osteoporosis was assessed with kappa statistics., Results: Findings from RA were correlated with those from spinal DXA (r = .56). The annual bone losses in healthy women, as measured with RA, radial DXA, and spinal DXA, were 0.47%, 0.47%, and 0.32%, respectively. Intergroup percentage decrements and t values obtained with RA were comparable to those obtained with radial and with spinal DXA. Receiver operating characteristic analysis showed no statistically significant differences. The odds ratios for RA, radial DXA, and spinal DXA were 2.1, 1.9, and 2.4, respectively. The kappa scores were 0.44 for both RA versus radial DXA and RA versus spinal DXA, and the score was 0.22 for radial DXA versus spinal DXA., Conclusion: RA appears to be a useful technique for assessing age- and menopause-related bone loss and for identifying women with osteoporosis.

Rationale and Objectives: The authors used direct magnification radiographs, combines with texture analysis, to investigate the trabecular structure of human vertebral specimens and compared these techniques with measurement of bone mineral density (BMD) by using quantitative computed tomography to predict bone strength., Methods: Direct magnification radiographs and BMD measurements were obtained from 38 motion segments from the thoracolumbar spines of 11 female human cadavers. Maximum compressive strength (MCS) was determined with a materials testing machine. Morphologic parameters, digital skeletons, and fractal dimension were obtained from the radiographs in three different regions of interest., Results: Correlations between BMD and MCS were statistically significant (r = .81, P < .01). With morphologic parameters, correlation coefficients of up to .64 (P < .01) were obtained. Use of multivariate regression analysis with one morphologic parameter (the width of the black pixels, or thicknessB) in addition to BMD improved correlations versus MCS (P < .01)., Conclusion: In an experimental setting, BMD showed statistically significant correlation with bone strength, whereas the structural parameters demonstrated only modest correlations. BMD together with one of these measures (thicknessB), however, showed the highest correlation.

We have evaluated the Lunar Expert-XL for standard bone mineral densitometry (BMD) and for morphometric imaging of the spine in the lateral projection. The short-term precision in vitro of the Expert-XL for BMD measurements was 0.7% for the Hologic and European spine phantoms, and the long-term stability (15-month) measurements had a 1.1% coefficient of variation. The precision in vivo for three operators examining a group of 10 premenopausal women was 0.9-1.5% for lumbar spine (L2-L4), 1.7-2.2% for the femoral neck, and 0.9% for the total hip region of interest. For a group of nine postmenopausal women, the lumbar spine, femoral neck, and total femur precision ranges were 2.0-2.4, 1.2-2.9, and 1.6-1.7% respectively. For L2-L4, BMD comparison between the Expert-XL and DPX-L yielded a correlation coefficient of r = 0.98, a slope of 0.86, and an intercept of 0.139 g/cm2. The femoral neck results were r = 0.92, slope = 1.00, and intercept = 0.03 g/cm2. In an evaluation of the Expert-XL for lateral morphometry, we employed a group of 16 postmenopausal women. Comparison of vertebral dimensions between the Expert-XL and radiographic morphometry showed strong agreement (r = 0.97), but the interobserver variability for vertebral height was higher for the Expert-XL than for radiographs (3-5% vs. 1-2%). In a subset of four women who had repeat scans, the interscan precision for measuring vertebral dimensions was 1.9, 4.1, and 43% for the L1-L4, T12-T8, and T7-T5 levels respectively. In the Expert-XL images, it was possible to identify clearly L4-T4 in 10 of 16 patients and L4-T6 in 15 of 16, indicating potential utility for vertebral fracture prescreening.

Objective: We undertook this study to quantify the relationship between bone mineral assessments of the lumbar spine using quantitative CT (QCT) and of the radius using peripheral QCT (pQCT) and to test the sensitivity of both techniques in detecting changes in bone mass that are related to age and osteoporosis., Subjects and Methods: Forty-two healthy premenopausal, 38 healthy postmenopausal, and 97 osteoporotic postmenopausal women were examined with pQCT of the distal radius and with QCT of the lumbar spine (L1-L4). The bone mineral density (BMD), bone mineral content (BMC), and a cross-sectional area of cortical bone were assessed at the distal radius. The BMD of trabecular and total bone and the BMC of total bone were assessed at the midvertebral bodies of the lumbar spine., Results: In the healthy women, correlations of radial BMD with spinal trabecular and total BMD were modest (r = .39 and r = .49, respectively) but were higher for total BMC (r = .79). All correlations in osteoporotic women (r = .19 for trabecular BMD, r = .31 for total BMD, and r = .47 for total BMC) were lower than those in healthy women. For measurement of spinal bone mass in healthy women, trabecular BMD showed a higher correlation with age (r = .81) and a larger relative annual decrease (1.2%) than did total BMD (r = .75, .78%) or total BMC (r = .54, .55%). At the radius, the highest correlations with age were found for total BMC (r = .57, .53%), cortical area (r - .52, .67%), and cortical BMC (r = .48, .78%). Age-adjusted odds ratios for prevalent vertebral fractures were highest for total (4.5) and trabecular (4.4) spinal BMD. For radial measurements, odds ratios were highest for both total BMD (2.3) and cortical area (2.3)., Conclusion: QCT of spinal trabecular bone showed the strongest capability for assessment of age-related bone loss and for discrimination of osteoporotic vertebral fractures. In comparison, pQCT of radial trabecular bone showed the weakest capability for these applications, and pQCT of radial cortical or total bone showed intermediate capability.

Objective: A study using quantitative CT (QCT) of the spine was carried out to determine whether the standard deviation (SD) of the bone mineral density (BMD) within a given region of interest (ROI) could be used as a parameter to evaluate osteoporosis., Materials and Methods: A low dose single energy protocol was used. The elliptical ROIs inside the trabecular bone of the vertebral bodies T12-L3 were analyzed for four patient groups: Group 1, 52 healthy premenopausal women (age 41 +/- 2 years); group 2, 119 healthy early postmenopausal women (53 +/- 4 years); group 3, 45 postmenopausal relatively healthy women (age 65 +/- 5 years); group 4, 26 osteoporotic women (age 67 +/- 5 years). Average group mean BMD values and their coefficients of variation (CV = SD/BMD) were calculated. The t values, percent decrements, z-scores, and analysis of variance (ANOVA) served to compare capabilities of the BMD and the CV to discriminate groups pairwise using all possible group combinations., Results: The use of z-scores and percent decrements gave ambivalent and mostly insignificant results. The CV performed better than BMD in separating group pairs (1,3), (1,4), (2,3), and (2,4), but BMD was superior for group pairs (1,2) and (3,4). Using SD as an independent variable in addition to age and BMD in the ANOVA did not significantly change r2 or the standard error of the estimate. The t test showed highly significant better discriminatory capabilities for BMD compared to CV>, Conclusion: The results of our study did not indicate a significant potential of the BMD SD as measured in trabecular single energy low dose spinal QCT to improve the discriminatory capabilities of BMD for a separation of osteoporotic from nonosteoporotic subjects.

The comparison of patient data among different dual x-ray absorptiometry (DXA) scanners is complicated because no universally accepted cross-calibration procedure or standard currently exists. This study was performed under the auspices of the International DXA Standardization Committee to establish appropriate cross-calibration parameters. Posteroanterior (PA) lumbar spine measurements of 100 women, ages 20-80 years (mean 52.6 +/- 16, range of BMD = 0.4-1.6 g/cm2) were obtained on a Norland XR26 Mark II, a Lunar DPX-L, and a Hologic QDR 2000 densitometer using standard procedures (pencil beam mode for all three scanners). Area, BMC, and BMD results from the different scanners were compared for all patients. In addition, the European spine phantom (ESP) and the European spine phantom prototype (ESP prototype), as well as standard phantoms from all three manufacturers, were evaluated on the three systems. To achieve universal scanner calibration, we used the intercept and slope of the patient's correlations and the value of the middle vertebra of the ESP as a reference point in a series of standardization formulas, and we have expressed the results as sBMD (mg/cm2). The correlations of the patients' spinal BMD values were excellent for each of the three scanner pairs. The average absolute difference in patient spinal BMD values (L2-4) between Hologic and Norland was 0.012 g/cm2 (1.3%); it was 0.113 g/cm2 (11.7%) between Hologic and Lunar and 0.118 g/cm2 (12.2%) between Norland and Lunar. The phantoms' regression lines approximated those of the patient regression lines, and the phantoms with only one measurement point were very close to the patients' regression lines. After applying the standardization formulas, the average absolute differences for the 100 patients were 28 mg/cm2 (2.7%) for Hologic/Norland, 23 mg/cm2 (2.2%) for Hologic/Lunar, and 29 mg/cm2 (2.8%) for Norland/Lunar. Average BMD results for the patients before correction were 0.972 mg/cm2 for Hologic, 1.100 g/cm2 for Lunar, and 0.969 g/cm2 for Norland. After correction, sBMD results for patients were 1045 mg/cm2 for Hologic, 1047 mg/cm2 for Lunar, and 1043 mg/cm2 for Norland. The standardization approach as performed in our study provided compatibility of DXA results obtained on different scanners.

In 100 patients (20 male, 80 female) radiographs of the lumbar spine were obtained in both planes, anteroposterior and lateral. Nine readers independently and without specific criteria or training assessed the radiographs for presence of osteopenia in the form of a binary decision. A posteranterior dual x-ray absorptiometry (PA DXA) measurement of the lumbar spine was performed in all patients using the Hologic QDR 1000 bone densitometer. A bone mineral density (BMD) of 0.83 g/cm2 (T-score about 2 SD and 2.5 SD lower than BMD in normal young female and male subjects respectively) was used as a threshold for the diagnosis of osteopenia. Complete agreement amongst the 9 readers was achieved in 43 patients. In 26 more patients at least 8 readers agreed. kappa-coefficients for interobserver variation ranged from 0.458 to 0.691 for reader pairs. For agreement between the observer ratings and the DXA results, kappa-coefficients ranging between 0.347 and 0.555 were found. The vast majority of readers agreed in the diagnosis of osteopenia in cases where the BMD was less than 0.73 g/cm2. Where the BMD was between 0.73 and 1.03 g/cm2 a substantial disagreement was found between reader evaluation and DXA measurement, and also amongst the readers. We conclude from our results that osteopenia can reliably be detected from lumbar spine radiographs by all readers only after a substantial amount of BMD is lost. On the other hand, a diagnosis based solely on PA DXA measurement of the spine may also lack accuracy, due to a substantial influence of degenerative changes of the lumbar spine and aortic calcification.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: To develop a method for assessing the presence and severity of radiographic features of osteoarthritis (OA) of the hip and hand, and thoracic and lumbar disc degeneration., Methods: An atlas illustrating scoring of individual radiographic features and summary grades for individual joints was developed. Three readers evaluated 31 pelvic films, 27 hand films, and 25 lateral lumbar and thoracic spine films selected from a community based sample of healthy elderly women. Interrater agreement between the 3 readers, and test-retest agreement for one of the readers, were estimated by the intraclass correlation coefficient (ICC) and kappa statistic., Results: Interrater agreement (ICC, unless otherwise noted) for individual radiographic features of the hip ranged from 0.66 for osteophytes to 0.80 for narrowing. For the 9 interphalangeal (IP) joints of the hand, agreement ranged from 0.42 (kappa) for sclerosis to 0.93 for narrowing, and for the lumbar spine from 0.55 (kappa) for sclerosis to 0.95 for narrowing. Interrater agreement for summary grades of radiographic findings was as follows: hip, 0.81; 5 distal interphalangeal joints (DIP), 0.89; 4 proximal interphalangeal joints (PIP), 0.82; and lumbar spine, 0.93. Intrarater agreement for summary grades was as follows: hips, 0.79; 5 DIP, 0.86; 4 PIP, 0.81; and lumbar spine, 0.90., Conclusion: We have developed reliable indices of the presence and severity of radiographic features of hip and hand OA and spinal disc degeneration for use in epidemiologic studies. The assessment includes grading of individual radiographic features, which allows for the independent variation in these features often found in OA and a summary grade of disease that is derived from the presence and severity of individual features.

Purpose: To report that calcification of lumbar disks may not show the usual low signal intensity on T1-weighted magnetic resonance (MR) images., Materials and Methods: The authors present five cases of high signal intensity on T1-weighted MR images of a lumbar disk that reflect the presence of calcium deposition., Results: In four cases there was conventional radiographic confirmation and in one case there was computed tomographic confirmation of the disk calcification, which corresponded to the high signal intensity seen on the MR studies. One patient had undergone surgical removal of a partially calcified protruding disk., Conclusion: Lumbar disk calcification can vary in signal intensity from low to high on T1-weighted MR images.

Persistent low back pain after surgery can be a severe diagnostic and therapeutic problem. By using MRI many causes of this failed back surgery syndrome (FBSS) can be disclosed. MRI is superior to other imaging modalities in this concern. In this article we describe the MR technique, normal and abnormal findings of the postoperative lumbar spine, such as persistent or recurrent disc herniation, epidural scar, spinal stenosis, pseudomeningocele, arachnoiditis, pseudarthrosis, hematoma, and infection.

To assess the overall severity of vertebral deformity for an individual, we developed the index of radiographic area (IRA), a computerized method for analyzing vertebral dimensions from lateral radiographs of the spine. Six coordinates for each vertebral body are recorded in a computer by means of a digitizer. A computer program identifies all abnormal vertebrae, computes the radiographic area of the remaining normal vertebrae, and then estimates the expected normal radiographic area for the abnormal vertebrae in that individual. Differences between the expected and observed radiographic area of all abnormal vertebrae are summed to produce the IRA score. The score correlated well with the quantitative score of vertebral deformity of an experienced radiologist (r = 0.85), and with the vertebral bone density by quantitative computed tomography (QCT) (r = 0.66). The IRA is a practical, standardized method for quantitating the overall severity of vertebral deformity in individuals who have vertebral fractures. Its reproducibility for longitudinal studies and clinical trials needs further study.

Segmental spinal instability was evaluated with magnetic resonance (MR) imaging, computed tomography (CT), and conventional radiography in 33 patients who had undergone surgical spinal fusion. In 16 of the 19 patients who had a diagnosis of solid fusion, the immobilized vertebral bodies demonstrated areas of high signal intensity on images with short repetition time (TR) and echo time (TE). The signal intensity of these areas was either less intense or normal on images with long TR and TE. In 10 of the 14 patients with segmental instability at the fusion site, subchondral vertebral bands of low signal intensity were shown on short TR/TE images, which demonstrated high signal intensity on long TR/TE images. All but two of the patients showed vertebral signal changes 12 or more months past fusion or onset of clinical symptoms. The vertebral MR signal intensity in solid lumbar fusions might be related to marrow composition changes resulting from decreased biomechanical stress, while the vertebral signal intensities in patients with unstable fusions might be related to reparative granulation tissue, inflammation, edema, and hyperemic changes. Magnetic resonance imaging appears to be unique in its assessment of functional fusion stability. Magnetic resonance may be most useful in patients symptomatic of fusion pseudarthrosis in whom conventional radiography and CT fail to demonstrate anatomic disruption.

Magnetic resonance (MR) imaging is a powerful diagnostic tool for patients with the failed back surgery syndrome. The multiplanar imaging capability, superior soft-tissue contrast resolution, and excellent tissue characterization are its major advantages. It displays the changes caused by surgical intervention as well as associated postoperative findings, many of which cause the failed back surgery syndrome. Most recently, gadolinium-DTPA-enhanced MR imaging of the spine, combined with noncontrast MR imaging, has shown heretofore unparallelled sensitivity and accuracy.

Quantitative CT (QCT) studies of trabecular vertebral bone tissue have been carried out in vitro on a GE CT/T 9800 scanner. Results of both single energy (SE) 80 kVp and dual energy (DE) 80/140 kVp QCT data are compared with chemical mineral analysis to determine accuracy. We examined 62 vertebral specimens, from 28 cadavers (19 male and 9 female with an age range of 19-93 years, mean = 60.4). Averaging the results of all vertebral bodies of the same individual for SEQCT versus ashweight, we found a correlation coefficient (r) of 0.94 (p less than 0.0001), a standard error of the estimate (SEE) of 12.2 mg/cm3 (calibrated to K2HPO4), with a coefficient of variation (CV) of 13.2% and an average underestimation of bone mineral content of 18.7 mg/cm3. The corresponding DEQCT results were r = 0.98 (p less than 0.0001), SEE = 7.4 mg/cm3, CV = 7.0%, and an average underestimation of 4.9 mg/cm3. The SE and DE results are correlated with r = 0.98 (p less than 0.0001), SEE = 8.0 mg/cm3, and CV = 8.7%. From our SEQCT data and the results of the chemical analysis of bone mineral and fat content we calculated a fat sensitivity of 7.7 mg/cm3 K2HPO4 per 100 mg/cm3 fat change for our scanner. Using an average fat variability of 87.5 mg/cm3, this leads to a fat-related uncertainty for the normative SEQCT data of 6.7 mg/cm3, which is far lower than the normal biological variation of 29.4 mg/cm3. Using tabulated normative data on fat content versus age and versus mineral content of 188 vertebral specimens from five collaborating centers, we derived a correction algorithm for QCT measurement that reduces our average underestimation to 0.88 mg/cm3 with an SEE of 12.1 mg/cm3. Hence, this correction procedure can be used to estimate the fat corrected absolute mineral density for research purposes or for scanners with high fat sensitivity. For the GE CT/T 9800 scanner, with a relatively low fat to mineral sensitivity at 80 kVp, the correction procedure is generally not recommended for clinical studies since it minimizes the average fat induced error but does not reduce the residual, partially fat related uncertainty. Finally, since the fat related uncertainty is small compared to biological variation, the correlation is high between SEQCT and DEQCT, and the radiation dose is lower and the precision higher for SEQCT, we suggest that most clinical diagnostic studies using the GE CT/T 9800 scanner for bone mineral determination employ SEQCT at 80 kVp.

MR tomography was used to assess functional lumbar stability in 30 patients with posterolateral fusions. The vertebral bodies of 9 of the 12 patients with unstable lumbar fusions presented with areas of decreased signal intensity on T1- and intermediately weighted images, which increased on T2-weighting. The vertebrae of 15 of the 18 patients with stable fusions demonstrated zones of increased signal intensity on T1- and intermediately weighted images, which were less intense or invisible on T2-weighing. Surgical correlation was available in 11 of the 30 patients studied. Hyperemia and inflammation appear to be responsible for the abnormal signal intensities in the patients with stable fusions, whereas an increase in adipose marrow due to decreased biomechanical stress is thought to account for the atypical signal intensities in the vertebral bodies of the patients with stable fusions. MR tomography seems to be a potential method for evaluating functional lumbar fusion stability. MR tomography may be particularly helpful in those patients with multiple back surgeries and possible instability, recurrent disc herniation, or postoperative fibrosis. MR is recommended in the patient, who appears clinically unstable, whose radiographs and CT, however, do not demonstrate fusion failure.

Quantitative computed tomography (QCT) measurements of bone mineral density, volume, and content were made of the spongious and compact portions of a vertebral body and of the total vertebral body in 19 osteoporotic patients (13 women and 6 men) and 20 normal (control) age- and sex-matched patients. Specifically, CT scans of 10mm thick transverse sections of L2 or L3 of each osteoporotic and control patient were subjected to QCT bone measurement with the use of K2HPO4 calibration for converting CT values into units (mg/ml) equivalent to bone mineral density. In every instance, a significant difference was found in the spongious vertebral bone mineral density (and content) between the osteoporotic and the paired normal groups. Even when the total vertebral bone mineral content was normal, the spongious vertebral bone mineral density was significantly less in the osteoporotic patients. Only in the osteoporotic men was a difference in compact bone density (and content) found; the osteoporotic men had a significantly lower compact bone mineral than did the normal male patients. This study shows that QCT can be applied to measurement of bone mineral density (and content) of both the anterior spongious and the more dense compact vertebral bone from a single section of a lumbar vertebra and that it is the anterior, spongious, vertebral bone rather than the compact vertebral bone that exhibits the more severe decrease in bone mineral density (and content) due to osteoporosis.

40 patients with spondylolisthesis and/or spondylolysis were studied by magnetic resonance imaging (MR), 12 of whom with correlation to CT. CT proved to be more sensitive in detecting pars defects than MR. Sagittal MR, however, was more accurate in assessing spondylolisthesis than axial CT. At present, CT is superior to MR in demonstrating bony abnormalities. MR appears indicated in the patient undergoing spinal fusion in whom detection of intervertebral disc degeneration in the levels above or below intended fusion may lead to extension of fusion to the degenerated levels. Lack of ionizing radiation makes MR an ideal diagnostic method in evaluating spondylolisthesis in children and adolescents.

Three-dimensional computed tomography (3-D-CT) and multiplanar CT reformations were performed in 42 patients who were clinically suspected of spinal instability following posterior lumbar fusion. Sagittal and coronal CT reformations demonstrated fusion pseudarthrosis more frequently than axial CT or conventional radiography. Three-dimensional CT cuts through the fusion revealed pseudarthrosis in most patients with positive 2-D images. In 5 patients, however, fusion appeared to be artifactually stable or unstable on 3-D cuts contrasting the 2-D images. Three-dimensional surface reconstructions demonstrated the complex anatomy of the fusion and showed superficial breaks. They were helpful in preoperative planning as well as intraoperative localization. 3-D-CT is a clinically useful adjunctive imaging method.

Vertebral trabecular bone mineral density of both healthy Japanese subjects and Japanese patients with osteoporosis was measured by quantitative computed tomography (QCT) technique. The age-related reduction rate in vertebral trabecular bone mineral density of control females averaged 1.1% per year, from age 20 to 80, with an accelerated loss demonstrated after age 40. In the male controls, trabecular bone mineral density declined by an average of 0.9% per year. These values were found to be similar to the University of California at San Francisco (UCSF) QCT data (US Caucasians: 1.2% for female, 0.72% for male). Therefore, it appears that age-related rates of trabecular bone loss in the lumbar vertebrae may be similar for both Japanese and Caucasians. However, when compared to average values in UCSF QCT data of comparable age and sex, the mean values in Japanese appear to be approximately 10-20 mg/cm3 lower than Caucasian counterparts. All female patients with osteoporosis as evidenced by atraumatic vertebral fracture had QCT values below 50 mg/cm3. It is suggested that the Japanese may have lower trabecular bone mineral density than Caucasians but may also have a lower threshold for fracture of the vertebrae. Further studies are needed to establish the possible racial differences in vertebral trabecular bone mineral density, and to determine whether these possible disparities are related to genetic differences, or to differences in body size, dietary intake, physical activity or other lifestyle/environmental factors.

Vertebral trabecular mineral content and peripheral cortical bone mineral were measured in 94 female and 44 male osteoporotic patients and compared to vertebral mineral values obtained for 323 control subjects in a cross-sectional study. The rate of change of spinal trabecular mineral with age (measured by quantitative computed tomography) in control females averaged 1.2% per year from age 20 to 80, with an accelerated loss demonstrated at the menopause. Trabecular bone mass in male controls declined an average 0.72% per year. Female osteoporotics had a mean decrement of 48 mg cm-3 (39%) compared to age-matched controls, whereas males were decreased 66 mg cm-3 (50%). Radial cortical bone was correlated with spinal mineral in osteoporotics for both males (r = 0.48) and females (r = 0.62). Vertebral compression fractures or wedging was generally absent in patients with vertebral mineral values above 110 mg cm-3, whereas almost all patients with values below 65 mg cm-3 had fractures. Quantitative computed tomography for measurement of vertebral trabecular bone mineral density is useful for defining those patients in whom the risk of vertebral fracture is increased.

Quantitative CT (QCT) is an established method for the noninvasive assessment of bone mineral content in the vertebral spongiosum and other anatomic locations. The potential strengths of QCT relative to dual photon absorptiometry (DPA) are its capability for precise three-dimensional anatomic localization providing a direct density measurement and its capability for spatial separation of highly responsive cancellous bone from less responsive cortical bone. The extraction of this quantitative information from the CT image, however, requires sophisticated calibration and positioning techniques and careful technical monitoring.

Fifteen nuclear magnetic resonance (NMR) studies of 14 patients with herniated lumbar intervertebral disks were performed on the UCSF NMR imager. Computed tomographic (CT) scans done on a GE CT/T 8800 or comparable scanner were available at the time of NMR scan interpretation. Of the 16 posterior disk ruptures seen at CT, 12 were recognized on NMR. Diminished nucleus pulposus signal intensity was present in all ruptured disks. In one patient, NMR scans before and after chymopapain injection showed retraction of the protruding part of the disk and loss of signal intensity after chemonucleolysis. Postoperative fibrosis demonstrated by CT in one patient and at surgery in another showed intermediate to high signal intensity on NMR, easily distinguishing it from nearby thecal sac and disk. While CT remains the method of choice for evaluation of the patient with suspected lumbar disk rupture, the results of this study suggest that NMR may play a role in evaluating this common clinical problem.

Three-dimensional (3-D) surface reconstructions and multiplanar computed tomography (CT) reformations were obtained in 30 patients with clinically suspected spinal fusion pseudarthrosis. The imaging studies were blind-reviewed and the results were compared with the clinical and surgical findings. Sagittal, planar, and curved coronal two-dimensional (2-D) reformations were more useful in the detection of bony nonunion than were axial CT scans, as the latter required more extensive analysis. Three-dimensional surface "cuts" adequately demonstrated pseudarthrosis in most cases. In some instances, however, segmentation artifacts created artifactual clefts or implied solidity, which contrasted with the interpretation of the 2-D images. Sagittal 3-D cuts were helpful in demonstrating bony central and lateral stenosis. Three-dimensional surface reconstructions demonstrated superficial clefts and outlined the complex anatomy of the spinal fusions, thus facilitating pre- and intraoperative planning. The amount of bone stock available for pseudarthrosis repair at the fusion site and the need for additional harvesting of bone from the iliac crest also could be assessed easily. 3-D CT proved to be useful as an adjunctive imaging method in the evaluation of posterior lumbar fusion patients suspected of pseudarthrosis.

CT has become the imaging modality of choice for diagnosing the specific cause of low back pain syndrome. This article describes and illustrates those abnormalities commonly associated with low back pain: disk herniation, spinal stenoses, facet joint abnormalities, spondylosis, inflammatory conditions of the lumbar spine, and sacroiliitis.

UnlabelledThe precision of Hologic Apex v2.0 analysis software is significantly improved from Hologic Delphi v11.2 software and is comparable to GE Lunar Prodigy v7.5 software. Apex and Delphi precisions were, respectively, 1.0% vs. 1.2% (L1-L4 spine), 1.l % vs. 1.3% (total femur), 1.6% vs. 1.9% (femoral neck), and 0.7% vs. 0.9% (dual total femur).IntroductionPrecision of bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry (DXA) is known to vary by manufacturer, model, and technologist. This study evaluated the precision of three analysis versions: Apex v2.0 and Delphi v11.2 (Hologic, Inc.), and Prodigy v7.5 (GE Healthcare, Inc.) independent of technologist skill.MethodsDuplicate spine and dual hip scans on 90 women were acquired on both Delphi and Prodigy DXA systems at three clinics. BMD measures were converted to standardized BMD (sBMD) units. Precision errors were described as a root-mean-square (RMS) standard deviations and RMS percent coefficients of variation across the population.ResultsApex and Delphi values were highly correlated (r ranged from 0.90 to 0.99). Excluding the right neck, the Apex precision error was found to be 20% to 25% lower than the Delphi (spine: 1.0% versus 1.2% (p < 0.05), total hip: 1.1% versus 1.3% (p < 0.05), right neck: 2.3% versus 2.6% (p > 0.1)). No statistically significant differences were found in the precision error of the Apex and Prodigy (p > 0.05) except for the right neck (2.3% versus 1.8% respectively, p = 0.03).ConclusionThe Apex software has significantly lower precision error compared to Delphi software with similar mean values, and similar precision to that of the Prodigy.