Diagnosis of osteoporosis in clinical practice

Does Bone Mineral Density Differ between Fan-Beam and Pencil-Beam?: A Meta-Analysis and Systemic Review

Background

Dual energy X-ray absorptiometry (DXA) has evolved from pencil-beam (PB) to narrow fan-beam (FB) densitometers. We performed a meta-analysis of the available observational studies to determine how different modes of DXA affect bone mineral density (BMD) measurements.

Methods

A total of 1,233 patients (808 women) from 14 cohort studies were included. We evaluated the differences in BMD according to the DXA mode: PB and FB. Additionally, we evaluated the differences in BMD between the 2 types of FB mode: FB (Prodigy) and the most recent FB (iDXA). Pairwise meta-analysis was performed, and weighted mean differences (WMD) were calculated for (total lumbar, total hip, and total body).

Results

No significant difference was observed in total lumbar (pooled WMD, −0.013; P=0.152) and total hip BMD (pooled WMD, −0.01; P=0.889), between PB and FB. However, total body BMD was significantly lower in the PB compared to the FB group (pooled WMD, −0.014; P=0.024). No significant difference was observed in lumbar BMD (pooled WMD, −0.006; P=0.567), total hip (pooled WMD, −0.002; P=0.821), and total body (pooled WMD, 0.015; P=0.109), between Prodigy and iDXA.

Conclusions

The results of this study warrant the recommendation that correction equations should not be used when comparing BMD from different modes. Further research is still needed to highlight the ways in which differences between DXA systems can be minimized.

Dual-energy CT in vertebral compression fractures: performance of visual and quantitative analysis for bone marrow edema demonstration with comparison to MRI

OBJECTIVE

To prospectively evaluate the performance of virtual non-calcium (VNC) dual-energy CT (DECT) images for the demonstration of trauma-related abnormal marrow attenuation in collapsed and non-collapsed vertebral compression fractures (VCF) with MRI as a reference standard.

MATERIALS AND METHODS

Twenty patients presenting with non-tumoral VCF were consecutively and prospectively included in this IRB-approved study, and underwent MRI and DECT of the spine. MR examination served as a reference standard. Two independent readers visually evaluated all vertebrae for abnormal marrow attenuation ("CT edema") on VNC DECT images; specificity, sensitivity, predictive values, intra and inter-observer agreements were calculated. A last reader performed a quantitative evaluation of CT numbers; cut-off values were calculated using ROC analysis.

RESULTS

In the visual analysis, VNC DECT images had an overall sensitivity of 84%, specificity of 97%, and accuracy of 95%, intra- and inter-observer agreements ranged from k = 0.74 to k = 0.90. CT numbers were significantly different between vertebrae with edema on MR and those without (p < 0.0001). Cut-off values provided sensitivity of 85% (77%) and specificity of 82% (74%) for "CT edema" on thoracic (lumbar) vertebrae.

CONCLUSIONS

VNC DECT images allowed an accurate demonstration of trauma-related abnormal attenuation in VCF, revealing the acute nature of the fracture, on both visual and quantitative evaluation.

Osteoporosis and the orthopaedic surgeon

During the recent years, data regarding osteoporosis has accumulated and indicates that osteoporotic fractures in Scandinavia still increase. At the same time diagnostics and treatments have been improved. However, only a minority of patients with fractures and osteoporosis become identified. Surgeons and hospitals treating fractures should find means to detect patients who suffer from fractures due to osteoporosis, and establish programs for further evaluation and adequate treatment.

Preventing male osteoporosis: prevalence, risks, diagnosis and imaging tests

There is no universal definition of an osteoporotic fracture. Fractures of the vertebra, hip, and forearm generally are considered osteoporotic fractures. There is an increasing recognition, however, that osteoporosis can lead to fractures at other anatomic sites, including the ribs, humerus, tibia, pelvis, and femur. Excluding these types of fractures could underestimate the total cost and impact of osteoporosis. There are a variety of risk factors for osteoporosis and fracture, but several methods can quantify a patient's risk, and these tools are valuable in guiding clinicians in effective intervention. The author hopes this brief review provides clinicians with an introduction and overview of osteoporosis and its risk factors, screening methods, and procedures. The field of urology is constantly evolving, with a growing need for clinicians to become more knowledgeable about preventive medicine. This and other articles should provide a good foundation for clinicians to alter the increasing prevalence of a medical condition that is one of the most preventable causes of morbidity and mortality in men.

Osteoporosis: a rapid review of risk factors and screening methods

Osteoporosis is a significant problem in women and it is beginning to become a recognized etiology of morbidity and mortality in men. However, before reviewing any potential therapies, it is imperative that clinicians first gain adequate knowledge on the risk factors for osteoporosis and fractures, and the various screening methods that are utilized in clinical practice. For example, advancing age, hormonal status, lifestyle, and overall diet are just a few of the potential risk factors. The majority of the risk factors in men seem to parallel those that have already been well known in women. Heel ultrasound (HUS), dual-energy X-ray absorptiometry (DEXA), and quantitative computerized tomography (QCT) are the most popular and effective methods utilized for osteoporosis screening. All of these imaging tests contain an inherent number of advantages and limitations. This brief review serves as a simplistic but important primer to a condition that is increasing in prevalence in a diverse area of medical fields.

Accelerated turnover of metaphyseal trabecular bone in mice overexpressing cathepsin K

This study is based on a hypothesis that overexpression of an osteoclast enzyme, cathepsin K, causes an imbalance in bone remodeling toward bone loss. The hypothesis was tested in transgenic (TG) mice harboring additional copies of the murine cathepsin K gene (Ctsk) identifiable by a silent mutation engineered into the construct. For this study, three TG mouse lines harboring 3-25 copies of the transgene were selected. Tissue specificity of transgene expression was determined by Northern analysis, which revealed up to 6-fold increases in the levels of cathepsin K messenger RNA (mRNA) in calvarial and long bone samples of the three TG lines. No changes were seen in the mRNA levels of other osteoclast enzymes, indicating that the increase in cathepsin K mRNA was not a reflection of activation of all osteoclast enzymes. Immunohistochemistry confirmed that cathepsin K expression in the TG mice was confined to osteoclasts and chondroclasts. Histomorphometry revealed a significantly decreased trabecular bone volume (BV), but, surprisingly, also a marked increase in the number of osteoblasts, the rate of bone turnover, and the amount of mineralizing surface (MS). However, monitoring of bone density in the proximal tibias of the TG mice with peripheral quantitative computed tomography (pQCT) failed to reveal statistically significant changes in bone density. Similarly, no statistically significant alterations were observed in biomechanical testing at the age of 7 months. The increases in parameters of bone formation triggered by increased cathepsin K expression is an example of the tight coupling of bone resorption and formation during the bone-remodeling cycle.

Bone mineral density of the lumbar spine in patients with advanced rheumatoid arthritis. Influence of functional capacity and corticosteroid use

We investigated factors that are related to generalized osteoporosis in advanced rheumatoid arthritis (RA). In this cross-sectional study we measured trabecular bone mineral density (BMD), by quantitative computerized tomography (QCT), in the lumbar spine of 57 patients with RA, most of whom were premenopausal women. In our material, 27 out of 57 patients (47%) had BMD <-1 SD expressed as Z-score and five patients had suffered from fractures. Our study shows that a cumulative corticosteroid dose (r = -0.41, p<0.010) and functional impairment (r = -0.37, p<0.050) were negatively related to spinal BMD, while daily intake of calcium correlated positively on BMD (r = 0.37, p<0.010). Our results indicate that low BMD is common in patients with advanced RA and it is associated with long-term corticosteroid use. Thus, in clinical practice we have to consider the benefits and harms of corticosteroid treatment and preventive therapy to osteoporosis.

Bone recovery after a gluten-free diet: a 5-year follow-up study

The purpose of our study was to investigate the recovery of bone disease in celiac patients during 5 years of a gluten-free diet. The study group consisted of 28 newly diagnosed celiac patients (9 men, 19 women) recruited between 1990 and 1991. Six patients withdrew from the 5-year follow-up. Compliance with the gluten-free diet was good: 96% at 1 year and 82% at 5 years. During the follow-up period, the body mass index increased significantly (8%). Both in men and women, bone mineral density (BMD) values determined by dual X-ray absorptiometry (DXA) increased at the lumbar spine (2%), the femoral neck (1%), the trochanter (6%), and the Wards' area (3%) during the follow-up. The increase in BMD was found already during the first year of follow-up. After 1 year, BMD increased or remained the same in 69% of the patients at the lumbar spine and in 67% of the patients at the femoral neck, 89% of patients at the throchanter, and 67% of patients at the Wards' area. During the 5-year follow-up, these figures were 52%, 46%, 68%, and 59%, respectively. At the baseline, 19 out of 28 patients, after 1 year, 14 out of 26 patients, and after 5 years, 2 out of 26 patients had low serum 25(OH)D vitamin values (p = 0.0001). A high serum parathormone value was noticed in 6 out of 25 patients at the baseline, but after 1 year, 5 of them showed normalized values (p = 0.03). According to our results, bone disease in celiac patients is cured in most patients during 5 years on a gluten-free diet. The improvement in BMD mostly occurred already within the first year after the establishment of a gluten-free diet.