Vertebral Morphometry Research Articles

The relative contribution of disc and vertebral morphometry to the angle of kyphosis in asymptomatic subjects

In order to investigate the relative contributions of vertebra and inter-vertebral disk to kyphosis, a series of 100 asymptomatic healthy women (age range 39-91 years) were studied to evaluate lateral dorsal appearances and possible related parameters of bone loss. Subjects underwent lateral dorsal spine radiography and single photon absorptiometry of the radius. There was a significant decrease in physical height in relation to age (P < 0.001) and this was directly related to an increasing thoracic kyphosis (P < 0.005). The angle of kyphosis was better related to the average anterior disc height (P < 0.001) than to average anterior vertebral height. The vertebral body ratio, however (anterior/posterior height), was more strongly related to angle of kyphosis than was disk ratio. The results also showed a fall in the proximal and distal radial bone mineral content with age (P < 0.001). These findings suggest that dorsal kyphosis as part of the ageing process may be as closely related to the physical integrity of the disc as to the vertebral body. Hence, therapy for age related bone mineral loss may have limited effect on a kyphotic deformity of the dorsal spine in otherwise asymptomatic patients.

Vertebral deformity in the thoracic spine in post-menopausal women: value of lumbar spine bone density.

Differential bone loss in the thoracic and lumbar spine is known to occur in some patients with osteoporosis. However, the discriminant value of lumbar spine bone densitometry in the detection of thoracic spine fractures in healthy, population-based women has not been established. The relationship between lumbar spine bone mineral density and thoracic spine vertebral deformities in a prospective study of 79 post-menopausal population-based women aged 45-65 years has been investigated. Lumbar spine bone mineral density was measured using dual energy X-ray absorptiometry, and vertebral morphometry was assessed from lateral thoracic spine radiographs. Seven women (9%) were found to have one or more vertebral deformities in the thoracic spine (reduction in anterior or posterior height > 25%). Only one of these had a lumbar spine bone mineral density T score below -2.5, whilst the T score was between -1 and -2.5 in three and greater than -1 in three. Two of these women also had lumbar spine vertebral deformity but lumbar spine radiographs were normal in the remaining five. There were no significant differences in age, height, weight, hormone replacement therapy use or bone mineral density between women with and without thoracic spine fractures. These results demonstrate that vertebral deformities in the thoracic spine occur in a proportion of healthy post-menopausal women in the absence of densitometric or radiographic evidence of osteoporosis in the lumbar spine. Although often asymptomatic, the significance of these fractures lies in the increased risk of further fractures. In the future, morphometric X-ray absorptiometric techniques may prove valuable in the detection of these fractures and avoid the need for conventional radiography.

Bone densitometry and vertebral morphometry with the lunar expert-XL: Assessment of precision

Bone densitometry and vertebral morphometry with the lunar expert-XL: Assessment of precision

Vertebral morphometry using radiographs: Comparison of manual and digitized images inexpert TM software

Vertebral morphometry using radiographs: Comparison of manual and digitized images inexpert TM software

Correlation between bone mineral density (BMD) of lumbar spine and vertebral morphometry

Correlation between bone mineral density (BMD) of lumbar spine and vertebral morphometry

A new method for semiautomated vertebral morphometry using digital images

A new method for semiautomated vertebral morphometry using digital images

Automated vertebral morphometry in DXA

Automated vertebral morphometry in DXA

Aging changes in vertebral morphometry

We analyzed the vertebral morphometry of healthy premenopausal women and their changes with age and menopause in order to better define the reference population for the clinical and epidemiological evaluation of vertebral fractures. Vertebral morphometry has been performed on lateral thoracic and lumbar spine films from 50 premenopausal and 76 postmenopausal normal women, age range 39-74 years. Vertebral heights and the anterior height/posterior height ratio are significantly lower in postmenopausal compared with premenopausal women. Vertebral anterior height decreases about 1.5 mm/year, whereas middle and posterior height decreases about 1.3 and 1.2/mm year, respectively. A statistically significant reduction of vertebral heights by around 1 mm/vertebra was observed in postmenopausal (n = 16) compared with premenopausal women (n = 20) of the same age (P < 0.05). The results demonstrate that vertebral heights are lower with advancing age and menopause and that the vertebral heights difference in elderly people is not only the consequence of a cohort effect. The results also contribute to better defining the reference population to be chosen for evaluating vertebral deformation.

The natural history of kyphosis in postmenopausal women.

A cross-sectional study of vertebral morphometry in 449 unscreened postmenopausal women, from the ages of 40 to 80, is reported. The wedge angles of thoracic vertebrae T4-12 were found to increase exponentially as a function of age, up to 70 years. In addition to age, the wedging phenomenon was found to be accentuated by increased bone turnover due to low calcium intake, reduced physical activity, each successive delivery, and breast feeding. Most of these variables were not correlated with isolated vertebral wedge angles, but rather with the sum of them (Sigma, sigma), assumed to assess the impact of those variables on thoracic kyphosis. In a subset of women, sigma was found to be inversely correlated with low spinal mineral density at L2-4. T-11 and T-12 were the vertebrae most frequently deformed (wedge angle exceeding mean +/- 3 SD in a group of 50 young healthy women, 25-45 years old). The distribution of deformed vertebrae was found to be significantly different from those qualified as "fractured" according to Kleerekoper et al.'s (1984) and Melton et al.'s (1989) criteria. The overall information afforded by past and present data indicates that in postmenopausal women, vertebral deformation may occur with the help of mechanical solicitations plus high bone remodeling rates, as well as by structural collapse (fracture). The information obtained does not allow one to quantify the relative contribution of each set of factors to the wedging phenomenon.

Vertebral fractures in men and women: how discriminative are bone mass measurements?

Vertebral fractures are associated with osteoporosis. This study examined men and women with vertebral deformation/fractures, as defined by vertebral morphometry. These were compared with a population derived group measured contemporaneously who were defined as having no vertebral deformation/fracture by the radiographs. All patients underwent a dual energy X-ray absorptiometry (DXA) scan of the spine and hip, and a broadband ultrasound attenuation (BUA) scan of their os calcis. The abilities of these two techniques were compared for their discriminatory powers in this type of fracture. The results showed that DXA hip and spine had a better discriminatory power in the female vertebral group compared with BUA. In males none of the bone measurements could discriminate between the fracture and non-fracture groups.

Vertebral shape, trabecular pattern, and spinal bone mineral density in osteoporosis

Vertebral morphometry and trabecular pattern were correlated to the bone mineral density (BMD) of the corresponding vertebra in 82 patients with osteoporosis. With lateral roentgenograms of the lumbar spine, the anterior, middle, and posterior vertebral heights of L2, L3, and L4 were measured, and the wedge index, concavity index, lumbar spine score, and relative central compression were calculated. The trabecular pattern was graded from normal to a disappearance of trabeculae. The BMD of the corresponding vertebrae was measured by dual photon absorptiometry. There were positive correlations between the BMD and the following measurements of biconcavity: the middle height (r=0.182, p=0.0086), concavity index (r=0.202, p=0.0034), lumbar spine score (r=0.147, p=0.0343), and relative central compression (r=0.179, p=0.0099). The trabecular pattern showed a negative correlation with the BMD (r=−0.141, p=0.0428). Although these correlations were statistically significant, the correlation coefficients and the coefficients of determination were small. Therefore, we may be able to use the degree of biconcavity and the trabecular pattern to differentiate severe osteoporosis from mild one, but these parameters are of limited value in the precise assessment of bone loss.

Bone mass, body weight, and seasonal bone changes.

Bone densitometry is now used widely in studies of bone mass. In just a few years, as a result of technological developments and efforts to control health care costs by using densitometric methods in the prevention of bone disease, mainly osteoporosis, we have progressed from simple forearm densitometry to total body densitometry with vertebral morphometry. However , recent studies show that radiogrammetry, a simple and inexpensive radiologic technique that is available at any hospital, is as effective as spinal densitometry, the technique most widely used in bone mass studies [1, 2]. Regardless of the value of bone densitometry in bone mass studies, its results can be expressed as either total body bone mineral content (TBBMC) and regional bone mineral content (RBMC), both in grams, or the more frequent total body bone mineral density (TBBMD) and regional bone mineral density (RBMD), both in g/cm 2. A recent development is the measurement of volumetric bone mass by axial or peripheral quantitative computed tomography (in g/cm 3) [3]. Regardless of how the measurements are expressed, normalization of bone mass to g/cm 2 or g/cm 3 minimizes sexual differences. Mazess et al. [4], prolific researchers of densitometric measurement of bone mass, find that sexual differences that are evident when bone mass measurements are expressed as grams of regional BMC are unapparent when bone mass is normalized for density. Although we have no wish to enter into debates, we agree with Dequeker and Geusens [5] that bone mass measurements should be expressed as BMC rather than BMD because BMC better discriminates the sexual differences in bone mass. Moreover, if skeletal calcium content is what really matters, TBBMC informs us of the absolute amount of total calcium (TBCa) because skeletal calcium represents a constant proportion of total mineral content [6]. As such, TBBMC is undoubtedly important in some disorders. We find that another advantage of expressing bone mass as regional BMC is that it correlates better with bone resistance to fracture than does regional BMD [7]. Changes in bone mass in men and women are influenced significantly by changes in weight [8, 9], weight being the principal determinant of bone mass in women [10]. Because of possible fluctuations in weight in the course of longitudinal studies [ l l ] , bone mass measurements should be evaluated in the light of changes in other body components. This has not been done in most studies, which overlook the possible relation between variations in bone mass and changes in weight. In fact, even over short time intervals, changes in

Vertebral deformity, bone mineral density, back pain and height loss in unscreened women over 50 years.

Bone mineral density (BMD) was measured in the lumbar spine using dual-energy X-ray absorptiometry in 222 unscreened women (aged 50-82 years), and information on back pain and historic loss of standing height was obtained at interview. Vertebral morphometry was performed on lateral spinal radiographs. The shape of the vertebral body was quantified using appropriate vertebral shape indices (VSIs), and vertebral deformities were identified using thresholds defined in terms of the means (M) and standard deviations (SD) of these VSIs for the whole group. Severity of deformity was defined as either grade 1 (M+2SD < VSI < M+3SD), grade 2 (M+3SD < VSI < M+4SD or grade 3 (VSI > M+4SD). Subjects with grade 1 vertebral deformities were older than subjects without such deformities, but did not have a reduced age-related Z-score of BMD. Grade 2 wedge and concave deformities were associated with a reduced age-related Z-score of BMD, suggesting that the aetiology of such deformities is closest to conventional concepts of 'osteoporotic fracture'. Grade 3 deformities were associated with neither increased age nor decreased BMD. Stature decreased in these subjects with age. Subjects reporting historic height loss had a higher mean number of wedge deformities. Subjects with back pain did not have a higher incidence of vertebral deformity than subjects without, confirming that many deformities were asymptomatic. Neither back pain nor historic loss of height were found to be associated with low spinal BMD.

A computerized technique for vertebral morphometry

A new technique for morphometric measurement of vertebral bodies has been described, in which a computerized image analysis system was used to digitize and measure standardized lateral radiographs of the thoracic and lumbar spine. The sources of error in the radiographic system and the image analysis system were assessed using vertebral phantoms and test images. Oblique projection in the radiographic image of a vertebra did not produce a significant error in the measured area. The radiographic magnification was approximately 35%. Optical non-uniformity was detected in the image analysis system, and was ascribed to the lens optics. The maximum intra-observer and inter-observer variations in vertebral area were 3.1% and 5.3% respectively for experienced observers. The technique is applicable to clinical studies of large populations, and has value in investigating vertebral deformity in the management of metabolic bone disease.

Vertebral morphometry in women aged 50-81 years

Vertebral dimensions and vertebral shape indices (VSI) were investigated in T4-L4 in 926 females aged 50-81 years. The most consistent finding was the increase of inferior antero-posterior dimension with age. Wedging and concavity also increased with age but the changes were not significant at all vertebral levels. The value of VSIs also varied with level. Thus a particular degree of VSI, considered normal at one level or at one age, would be outside the reference range at a different level or age group. The number of subjects identified as osteoporotic by skewness (5.4%) or in excess of three standard deviations from the mean (6.5%) was much lower than in recent reports from North America. The number of subjects contributing to a skewed distribution increased with age from 0.5% at 55-59 years to 10.0% at 75-79 years. Change with age in the antero-posterior dimension could increase load-bearing area in older subjects, but the decline in bone density will be increased as a declining bone mineral content occupies a larger volume.

Outcome variables in osteoporosis trials

The conduct of controlled clinical trials examining the anti-fracture efficacy of potential therapies for osteoporosis is a relatively new and developing science. We have reviewed several aspects of data acquisition, emphasizing that bone mass measurement and, similarly, back pain can only be regarded as ancillary outcome variables. Serial measurement of stature when performed in a precise manner may be an inexpensive, quick, and convenient surrogate outcome variable, most applicable to large multi-center studies. The only true end-point of such trials is the radiographic documentation of new vertebral fracture occurrence. Techniques for obtaining serial radiographs and assessing vertebral morphometry with good quality control have been described. Important questions still need to be resolved concerning the most appropriate criteria for defining incident fractures and for calculating fracture frequency. Implications regarding trial sample size requirements are discussed.

A comparison of morphometric definitions of vertebral fracture : J. Bone Miner. Res. 1991 6/1 (25–34)

To compare the accuracy of several approaches for defining prevalent vertebral fractures from measurements of vertebral dimensions (morphometry), we measured the lateral dimensions of vertebral bodies of 115 normal premenopausal and 100 postmenopausal women. Of the postmenopausal women two observers agreed that 49 had definite vertebral fractures and 38 were definitely normal. Using these classifications as an independent reference, women were then classified as fractured or normal by several definitions based on vertebral morphometry. No morphometric definition of vertebral fracture agreed perfectly with the consensus classifications. In general, definitions that involved combinations of measurements of anterior (Ha), middle (Hm), and posterior (Hp) vertebral height classified women more accurately than did definitions based on a single measurement or ratio. The Ha/Hp ratio produced many false positives unless it was adjusted for normal variations in the shapes of different vertebral bodies. Definitions of fracture based on a greater than 15% reduction in heights or ratios had higher sensitivity but more false positives than definitions that used a more stringent (greater than 20%) criterion. All morphometric definitions of vertebral fracture separated the post-menopausal women into two groups (fractured and normal) that had significantly (P less than 0.001) different mean spine bone density by quantitative computed tomography. Definitions that had the lowest rates of false positives also produced the largest differences in bone density between those defined as fractured and those defined as normal.

A randomized trial of sodium fluoride as a treatment for postmenopausal osteoporosis

The anti-fracture efficacy of sodium fluoride (NaF) was evaluated in 84 postmenopausal white women with spinal osteoporosis. The dose of NaF used was 75 mg/day and all patients in this prospective, randomized, double-blind, placebo-controlled clinical trial received calcium supplements (carbonate salt) 1500 mg/day in addition to participating in a structured physical therapy program. For each of the outcome measures (change in stature, change in cortical bone mass in the forearm and development of new vertebral fractures determined by change in vertebral morphometry and by scintigraphy) there was no significant difference between the fluoride or placebo treated groups. Side effects, predominantly gastrointestinal symptoms and the development of the painful lower extremity syndrome, occurred significantly more frequently in the fluoride group (P less than 0.05). Peripheral fractures were not more frequent in the fluoride group. We conclude that, in the dose and manner used in this study, NaF is no more effective than placebo in retarding the progression of spinal osteoporosis. There is no role for NaF in the treatment of osteoporosis outside the confines of clinical research.

A comparison of morphometric definitions of vertebral fracture

To compare the accuracy of several approaches for defining prevalent vertebral fractures from measurements of vertebral dimensions (morphometry), we measured the lateral dimensions of vertebral bodies of 115 normal premenopausal and 100 postmenopausal women. Of the postmenopausal women two observers agreed that 49 had definite vertebral fractures and 38 were definitely normal. Using these classifications as an independent reference, women were then classified as fractured or normal by several definitions based on vertebral morphometry. No morphometric definition of vertebral fracture agreed perfectly with the consensus classifications. In general, definitions that involved combinations of measurements of anterior (Ha), middle (Hm), and posterior (Hp) vertebral height classified women more accurately than did definitions based on a single measurement or ratio. The Ha/Hp ratio produced many false positives unless it was adjusted for normal variations in the shapes of different vertebral bodies. Definitions of fracture based on a greater than 15% reduction in heights or ratios had higher sensitivity but more false positives than definitions that used a more stringent (greater than 20%) criterion. All morphometric definitions of vertebral fracture separated the post-menopausal women into two groups (fractured and normal) that had significantly (P less than 0.001) different mean spine bone density by quantitative computed tomography. Definitions that had the lowest rates of false positives also produced the largest differences in bone density between those defined as fractured and those defined as normal.

Bone mineral mass associated with postmenopausal vertebral deformities

Vertebral morphometry on thoracic and lumbar spine radiographs and bone mass measurements were carried out on 215 patients investigated for postmenopausal osteoporosis. Bone mineral mass was measured on the central third of the skeleton by neutron activation analysis and the result, normalized for body size, expressed as a calcium bone index (CaBI). The normal CaBI value for females (20–40 years) is 0.97 (0.11) with a lower limit for these young, normal women, of 0.75. Vertebral compression deformity was defined as a mean height more than 15% lower than adjacent normal vertebrae. Thoracic and lumbar anterior wedge deformities and central compression were defined as anterior/posterior ( A P ) or mid/posterior ( M P ) height ratios of <0.75. For the 129 patients without vertebral deformities, the mean CaBI was 0.80 (0.12) (1 SD) and 32% of these patients had CaBI values below the normal young adult range (CaBI < 0.75). In 20 patients, vertebral deformities were limited to 1 or 2 mid-thoracic vertebrae, and the mean CaBI values for these 20 patients was 0.81 (0.15), equal to that for patients without any vertebral deformity. For the remaining 67 patients, (i.e., patients with one or more vertebral deformities involving at least one distal thoracic or one lumbar vertebra) the mean CaBI value was 0.66 (0.10), 17% below the value for patients without vertebral deformities. Low CaBI values (CaBI <0.75) were observed in 87% of these patients, consistent with the diagnosis of osteoporotic fractures. Based on our CaBI results, however, mid-thoracic deformity was not associated with significant osteopenia and is not, therefore, diagnostic of osteoporotic fracture.