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DEXA scan limitations

DEXA scan limitations

Limitatjons Requirements. Small Healthy alternatives to sugar consumption Non-irritating laundry detergents normally be observed between scans ljmitations to differences in positioning and usually are not significant. Pediatric Content. Bala Y, Zebaze R, Ghasem-Zadeh A, Atkinson EJ, Iuliano S, Peterson JM, Amin S, Bjornerem A, Melton LJ 3rd, Johansson H, et al.

DEXA scan limitations -

This procedure is important for diagnosing seeing if someone has osteoporosis or bone thinning and may be repeated over time to track changes in bone density. The amount of radiation used in DEXA scans is very low and similar to the amount of radiation used in common x-rays.

Although we all are exposed to ionizing radiation every day from the natural environment, added exposures can slightly increase the risk of developing cancer later in life.

Your healthcare provider may recommend a DEXA scan to test for osteoporosis or thinning of your bones. Screening for osteoporosis is recommended for women who are 65 years old or older and for women who are 50 to 64 and have certain risk factors, such as having a parent who has broken a hip.

However, there are other risk factors for osteoporosis besides age and gender, such as some intestinal disorders, multiple sclerosis, or low body weight. Your healthcare provider may recommend a DEXA scan if you have any of these other risk factors. DEXA scans should be used when the health benefits outweigh the risks.

Talk to your healthcare provider about any concerns you have before a DEXA scan. Find information on special considerations pregnant women and children. Learn more about the benefits and risks of imaging tests, including nuclear medicine, and how to reduce your exposure to radiation.

DEXA scans are different from other imaging procedures because they are used to screen for a specific condition. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Radiation and Your Health. Section Navigation. Facebook Twitter LinkedIn Syndicate. Radiation in Healthcare: Bone Density DEXA Scan Minus Related Pages. What You Should Know Your healthcare provider may recommend a DEXA scan to test for osteoporosis or thinning of your bones.

Nearly 1 in 5 women and 1 in 20 men over the age of 50 are affected by osteoporosis. Osteoporosis increases the risk for broken bones and can have serious effects in older adults. What To Expect Before the procedure Make sure to let your healthcare provider or radiologist medical professional specially trained in radiation procedures if you are pregnant or think you may or could be pregnant.

Dress in loose, comfortable clothing. Metal can interfere with test results. They are usually located in hospitals and medical offices. Central devices have a large, flat table and an "arm" suspended overhead.

Peripheral devices measure bone density in the wrist, heel or finger and are often available in drugstores and on mobile health vans in the community. The pDXA devices are smaller than the central DXA devices, weighing only about 60 pounds. They may have a portable box-like structure with a space for the foot or forearm to be placed for imaging.

Other portable technologies such as specially designed ultrasound machines, are also sometimes used for screening.

However, central DXA is the standard technique. The DXA machine sends a thin, invisible beam of low-dose x-rays with two distinct energy peaks through the bones being examined.

One peak is absorbed mainly by soft tissue and the other by bone. The soft tissue amount can be subtracted from the total and what remains is a patient's bone mineral density. DXA machines feature special software that compute and display the bone density measurements on a computer monitor.

In the central DXA examination, which measures bone density of the hip and spine, the patient lies on a padded table.

An x-ray generator is located below the patient and an imaging device, or detector, is positioned above. To assess the spine, the patient's legs are supported on a padded box to flatten the pelvis and lower lumbar spine.

To assess the hip, the patient's foot is placed in a brace that rotates the hip inward. In both cases, the detector is slowly passed over the area, generating images on a computer monitor.

You must hold very still and may need to hold your breath for a few seconds while the technologist takes the x-ray. This helps reduce the possibility of a blurred image.

The technologist will walk behind a wall or into the next room to activate the x-ray machine. The peripheral tests are simpler. The finger, hand, forearm or foot is placed in a small device that obtains a bone density reading within a few minutes.

An additional procedure called Vertebral Fracture Assessment VFA is now being done at many centers. VFA is a low-dose x-ray examination of the spine to screen for vertebral fractures that is performed on the DXA machine.

The DXA bone density test is usually completed within 10 to 30 minutes, depending on the equipment used and the parts of the body being examined. You will probably be asked to fill out a questionnaire that will help the doctor determine if you have medical conditions or take certain medications that either increase or decrease your risk of a fracture.

The World Health Organization has recently released an online survey that combines the DXA results and a few basic questions and can be used to predict year risk of hip fracture or other major osteoporotic fractures for post-menopausal women.

Routine evaluations every two years may be needed to see a significant change in bone mineral density, decrease or increase. Few patients, such as patients on high dose steroid medication, may need follow-up at six months. A radiologist , a doctor trained to supervise and interpret radiology examinations, will analyze the images.

The radiologist will send a signed report to your primary care or referring physician who will discuss the results with you. DXA scans are also interpreted by other physicians such as rheumatologists and endocrinologists. A clinician should review your DXA scan while assessing the presence of clinical risk factors such as:.

T score — This number shows the amount of bone you have compared with a young adult of the same gender with peak bone mass. A score of -1 and above is considered normal. A score between A score of The T score is used to estimate your risk of developing a fracture and also to determine if treatment is required.

Z score — This number reflects the amount of bone you have compared with other people in your age group and of the same size and gender. If this score is unusually high or low, it may indicate a need for further medical tests. Small changes may normally be observed between scans due to differences in positioning and usually are not significant.

Doctors take special care during x-ray exams to use the lowest radiation dose possible while producing the best images for evaluation. National and international radiology protection organizations continually review and update the technique standards radiology professionals use.

Modern x-ray systems minimize stray scatter radiation by using controlled x-ray beams and dose control methods. This ensures that the areas of your body not being imaged receive minimal radiation exposure.

Please type your comment or suggestion into the text box below. Note: we are unable to answer specific questions or offer individual medical advice or opinions. org is not a medical facility. Please contact your physician with specific medical questions or for a referral to a radiologist or other physician.

To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database. This website does not provide cost information.

The costs for specific medical imaging tests, treatments and procedures may vary by geographic region. Web page review process: This Web page is reviewed regularly by a physician with expertise in the medical area presented and is further reviewed by committees from the Radiological Society of North America RSNA and the American College of Radiology ACR , comprising physicians with expertise in several radiologic areas.

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Toggle navigation. What is a bone density Scan? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I experience during and after the procedure?

Who interprets the results and how will I get them? What are the benefits vs. What are the limitations of a bone density scan?

Bone density testing is strongly recommended if you: are a post-menopausal woman and not taking estrogen. have a personal or maternal history of hip fracture or smoking.

are a post-menopausal woman who is tall over 5 feet 7 inches or thin less than pounds. are a man with clinical conditions associated with bone loss, such as rheumatoid arthritis, chronic kidney or liver disease.

use medications that are known to cause bone loss, including corticosteroids such as Prednisone, various anti-seizure medications such as Dilantin and certain barbiturates, or high-dose thyroid replacement drugs. have type 1 formerly called juvenile or insulin-dependent diabetes, liver disease, kidney disease or a family history of osteoporosis.

have high bone turnover, which shows up in the form of excessive collagen in urine samples. have a thyroid condition, such as hyperthyroidism.

have a parathyroid condition, such as hyperparathyroidism. have experienced a fracture after only mild trauma. have had x-ray evidence of vertebral fracture or other signs of osteoporosis.

The Vertebral Fracture Assessment VFA , a low-dose x-ray examination of the spine to screen for vertebral fractures that is performed on the DXA machine, may be recommended for older patients, especially if: they have lost more than an inch of height. have unexplained back pain.

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Video

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QCT limitarions still a useful technique for evaluating patients with certain rheumatologic conditions, including advanced degenerative disease of the spine, diffuse idiopathic skeletal hyperostosis DISHLink says.

QCT allows volumetric measurements of the lumbar spine and proximal femur, which are independent of body size, and is able to separate trabecular and cortical compartments of the bone. The obvious limitations of measurements of bone mineral density for assessing fracture risk has led to the development of measures of bone architecture, because the trabecular bone structure is an indication of strength.

While most of these techniques will remain research tools because of their complexity and cost, one that can and is being used clinical practice is the trabecular bone score, he says. But there is some evidence that the trabecular bone score is useful for certain rheumatologic disorders, particularly rheumatoid arthritis and patients using glucocorticosteroids, and the International Society for Clinical Densitometry ICSD has embraced the technique, he says.

Unfortunately, there is not much else on the horizon for routine clinical practice, Link says. What is most important, he emphasises, is for rheumatologists to have a relatively low threshold for ordering a bone mineral density test because patients rheumatologic disorders, especially inflammatory disorders, are so much at risk of fractures, and it vital that these patients get treated early and in the correct way to avoid devastating fractures.

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: DEXA scan limitations

Dual-energy X-ray absorptiometry (DXA, previously DEXA) Benefits and Risks in Arizona Risedronate slows or partly reverses cortical and trabecular microarchitectural deterioration in postmenopausal women. FDA News. DEXA scans are different from other imaging procedures because they are used to screen for a specific condition. Article PubMed PubMed Central CAS Google Scholar. The adult skeleton is composed of uniquely shaped structures, each of which coordinately adapts its morphology and tissue-level material properties to support the physiological loads encountered during daily activities.
The Pros and Cons of DXA-What Are the Alternatives?

If an x-ray is necessary, the doctor will take precautions to minimize radiation exposure to the baby. See the Radiation Safety page for more information about pregnancy and x-rays.

Most of the devices used for DXA are central devices, which are used to measure bone density in the hip and spine. They are usually located in hospitals and medical offices. Central devices have a large, flat table and an "arm" suspended overhead. Peripheral devices measure bone density in the wrist, heel or finger and are often available in drugstores and on mobile health vans in the community.

The pDXA devices are smaller than the central DXA devices, weighing only about 60 pounds. They may have a portable box-like structure with a space for the foot or forearm to be placed for imaging. Other portable technologies such as specially designed ultrasound machines, are also sometimes used for screening.

However, central DXA is the standard technique. The DXA machine sends a thin, invisible beam of low-dose x-rays with two distinct energy peaks through the bones being examined. One peak is absorbed mainly by soft tissue and the other by bone. The soft tissue amount can be subtracted from the total and what remains is a patient's bone mineral density.

DXA machines feature special software that compute and display the bone density measurements on a computer monitor. In the central DXA examination, which measures bone density of the hip and spine, the patient lies on a padded table.

An x-ray generator is located below the patient and an imaging device, or detector, is positioned above. To assess the spine, the patient's legs are supported on a padded box to flatten the pelvis and lower lumbar spine.

To assess the hip, the patient's foot is placed in a brace that rotates the hip inward. In both cases, the detector is slowly passed over the area, generating images on a computer monitor. You must hold very still and may need to hold your breath for a few seconds while the technologist takes the x-ray.

This helps reduce the possibility of a blurred image. The technologist will walk behind a wall or into the next room to activate the x-ray machine. The peripheral tests are simpler. The finger, hand, forearm or foot is placed in a small device that obtains a bone density reading within a few minutes.

An additional procedure called Vertebral Fracture Assessment VFA is now being done at many centers. VFA is a low-dose x-ray examination of the spine to screen for vertebral fractures that is performed on the DXA machine. The DXA bone density test is usually completed within 10 to 30 minutes, depending on the equipment used and the parts of the body being examined.

You will probably be asked to fill out a questionnaire that will help the doctor determine if you have medical conditions or take certain medications that either increase or decrease your risk of a fracture. The World Health Organization has recently released an online survey that combines the DXA results and a few basic questions and can be used to predict year risk of hip fracture or other major osteoporotic fractures for post-menopausal women.

Routine evaluations every two years may be needed to see a significant change in bone mineral density, decrease or increase. Few patients, such as patients on high dose steroid medication, may need follow-up at six months.

A radiologist , a doctor trained to supervise and interpret radiology examinations, will analyze the images. The radiologist will send a signed report to your primary care or referring physician who will discuss the results with you.

DXA scans are also interpreted by other physicians such as rheumatologists and endocrinologists. A clinician should review your DXA scan while assessing the presence of clinical risk factors such as:. T score — This number shows the amount of bone you have compared with a young adult of the same gender with peak bone mass.

A score of -1 and above is considered normal. A score between A score of The T score is used to estimate your risk of developing a fracture and also to determine if treatment is required.

Z score — This number reflects the amount of bone you have compared with other people in your age group and of the same size and gender. If this score is unusually high or low, it may indicate a need for further medical tests. Small changes may normally be observed between scans due to differences in positioning and usually are not significant.

Doctors take special care during x-ray exams to use the lowest radiation dose possible while producing the best images for evaluation. National and international radiology protection organizations continually review and update the technique standards radiology professionals use.

Modern x-ray systems minimize stray scatter radiation by using controlled x-ray beams and dose control methods. This ensures that the areas of your body not being imaged receive minimal radiation exposure.

Please type your comment or suggestion into the text box below. Note: we are unable to answer specific questions or offer individual medical advice or opinions. org is not a medical facility. Please contact your physician with specific medical questions or for a referral to a radiologist or other physician.

To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database. This website does not provide cost information.

The standard locations for DXA measurement are the L1-L4 lumbar spine, hip, and forearm. These reference locations were originally selected because morbidity from fractures at these locations is high, especially at the spine and hip.

DXA results are reported as the standard deviation SD from a population mean, comparing the subject to a population at peak bone mass T-score and to an age-matched population Z-score. Since peak bone mass occurs at between 30 and 40 years of age, it is appropriate to use Z-scores in children and young adults who have yet to achieve peak bone mass.

The distribution of bone density across a population is dependent on race, age and gender. For example, African-Americans have lower rates of fracture compared to US Caucasians and Asians and this parallels the population distribution differences among races [ 27 ].

In one study, the age-adjusted mean for femoral neck BMD was 0. Because of such racial and ethnic differences, the significance of T-scores must be considered based on the fracture risk of ethnic and racially matched persons.

A similar rationale can be applied to men who have larger skeletal structures compared to women. To control for racial differences, DXA calculates T-scores using normative databases based on NHANES III data that include non-Hispanic White, Black, Hispanic and Asian individuals [ 29 ].

A pediatric normative base is also available. As stated before, bone size is directly related to strength. DXA does not account for bone size in assessing fracture risk. Attempts to correct bone size for height and weight have been reported [ 30 ]. Some DXA manufacturers allow for weight correction in the calculation of Z-scores to adjust for an expected decrease in fracture risk as weight increases.

Height correction is especially important in assessing fracture risk in children affected by short stature or growth delay [ 31 ].

DXA images are a 2-dimensional vertical and horizontal condensation of a 3-dimensional structure. As such, bone thickness is not measured in this scan.

The BMC measured reflects the amount of cortical and trabecular tissue present within a structure that acts to attenuate the X-ray signal; bones with more tissue attenuate the signal to a greater degree resulting in a higher gray value and BMC measure. Bone area is a measure of the size of the ROI.

For the hip, the ROI width is fixed and thus variation in bone area reflects differences in external bone size. The ratio of these two variables provides a measure of the mass density but not a measure of morphology or material properties.

Further, BMD does not differentiate whether the variation in BMD arises from differences in cortical mass, trabecular mass, or external bone size. Conventional wisdom is that women uniformly lose endosteal and trabecular bone in a similar pattern.

Recent data however suggest that the pattern of bone loss with aging in women is not uniform [ 32 ]. Bone shape and size at the menopause transition may in fact have a critical role in determining long-term bone loss with aging. Women with narrower femoral necks experienced modest decreases in BMC compared to those with wider femoral necks Fig.

But, women with narrow femoral necks also had larger increases in femoral neck area compared to women with wider femoral necks. BMD is the quotient of the BMC divided by the area. Because the larger increase in the denominator area in women with narrow femoral necks is similarly matched by the larger decrease in the numerator BMC in women with wide femoral necks, the result is that both groups have similar losses in BMD over time but for very different reasons.

The impact of these structural and mass changes on strength is currently under investigation. Areal BMD as determined by DXA declines with aging for different reasons. With aging, women with smaller femoral necks tend to increase bone area through an increase in cortical thickness by an increase in periosteal and endosteal bone formation.

Since BMD may only decrease slightly but bone area increases more, the result is lower areal BMD as measured by DXA despite likely having little change in bone strength. In the case of women with larger femoral necks, the endosteal cortex undergoes excessive resorption without periosteal expansion resulting in a thinner cortex.

The result is a lower BMC without significant change in bone area. The DXA areal BMD decreases and may result in a bone with less strength. Adapted from Jepsen, et al. JBMR [ 32 ]. Other than BMD, fracture risk is dependent on bone geometry, microarchitecture, microdamage, rate of bone turnover, and mineralization—all of which contribute to bone strength.

TBS indirectly assesses skeletal texture using DXA images and can be used to predict the risk of spine and hip fractures in women and men above the age of It has been validated in multiple cohorts with large numbers of subjects and shown to improve fracture risk prediction beyond that obtained by DXA.

TBS is available for clinical use in the United States [ 33 ]. The TBS is a textural index based on evaluating the pixel gray-level variations in the lumbar DXA image [ 34 ]. Well-structured bone produces 2-D DXA images that are homogenous with small gray-value amplitude variations. On the other hand, bone that is of poor quality produces higher gray-value amplitudes.

TBS is a unitless calculation of the sum of the squared gray-level differences between pixels at a specific distance. The steeper slope represents well-structured bone while the lower slope is suggestive of poorer architecture.

TBS is typically measured at the L1-L4 lumbar spine LS , the same sites used for DXA. The results are provided for each vertebral body as well as the composite for L1-L4. Unlike DXA, osteoarthritic changes have little impact on data generated by TBS. Several studies have shown that TBS predicts clinical, hip and vertebral fractures in postmenopausal women [ 35 , 36 ].

Some longitudinal studies have reported that TBS predicts fracture risk in men over the age of 40 but data on premenopausal women are lacking [ 37 , 38 ].

In addition, a meta-analysis of 14 prospective population-based cohorts reported that TBS provided additional information on the year fracture probability as estimated by the standard FRAX tool [ 39 ].

A low TBS would increase the FRAX risk of major osteoporotic fracture by 1. Changes in TBS are much smaller than LS BMD with osteoporosis treatment and therefore the role of using TBS to monitor patients on therapy is uncertain.

There is no data on the impact of a change in TBS on fracture risk. QUS can provide information on bone structure and fragility. Due to its use of low-frequency ultrasound it is safe and a relatively inexpensive method to assess for osteoporosis.

The two main parameters measured are the velocity of sound VOS and broadband US attenuation BUA. Data provided by QUS of the heel have been shown to correlate with the risk of fracture [ 41 ] but it is not used routinely for diagnosis of osteoporosis.

QCT provides volumetric 3D measurements by utilizing a low dose scan protocol and offers adequate details of the cortical and trabecular bone to generate reasonable estimates of strength through engineering-based analyses such as finite element analysis FEA and probabilistic modeling.

QCT is most commonly studied at the lumbar spine and hip. A variation of QCT, high-resolution peripheral quantitative computed tomography HR-pQCT , is mostly used to assess tibia and radius bone architecture and density.

The associations between HR-pQCT-based vertebral bone measurements and prevalent vertebral fractures depend on the spinal locations of both bone measurement and fracture [ 42 , 43 ].

An unclear correlation between QCT and other non-vertebral osteoporotic fractures along with higher exposure to ionizing radiation and cost have resulted in an infrequent use of these scans.

In addition, large precision errors with repeat measurements and unclear methods to adjust for variation in marrow fat and soft tissue density remain challenges for wider clinical use of QCT.

Until recently, treatment decisions were made primarily using T-scores but the over-reliance on this score has resulted in over-treatment, especially in younger patients who may in fact have a lower fracture risk. Using these risk factors and BMD data, fracture prediction algorithms have been developed.

It is the most widely used fracture prediction algorithm. The score provides a year probability of having a hip or major osteoporotic fracture with or without data on femoral neck BMD. The algorithm has been well validated in independent cohorts [ 45 ].

In addition to demographic variables and BMD or T-scores, the Garvan calculator takes into account the number of falls. The tool has been validated and is found to be clinically useful in predicting fractures in those at high risk [ 46 ]. Other calculators such as Osteoporosis Canada and FORE FRC v 2.

The Male Osteoporosis Risk Estimation Score MORES was reported to be a better tool to predict hip osteoporosis in men compared to FRAX [ 47 ]. While acknowledging that these calculators do not include all risk factors and can underestimate the fracture risk, they serve as a valuable tool to assist physicians in assessing risk with one long-term goal of avoidance of treatment in patients at low fracture risk [ 48 ].

BTMs are released during bone remodeling and can be measured in blood or urine. BTMs provide an assessment of bone remodeling rate and are surrogate end-points for fracture, bone quality and effectiveness of the therapy. They are grouped into two broad categories: bone resorption and bone formation markers.

Collagen degradation products, namely C-terminal cross-linked telopeptide of type 1 collagen βCTX , are released during bone resorption and reflect osteoclast activity. Bone formation markers such as procollagen type I N-terminal propeptide PINP and procollagen type I C-terminal propeptide PICP are peptides derived from posttranslational cleavage of type I procollagen molecules by proteases at the N- and C-terminus, respectively.

These markers reflect osteoblast function and activity. Commercially available βCTX assays have been developed with low method-specific difference and inter-assay variability.

βCTX itself demonstrates significant variation due to circadian rhythm and food intake. It is best measured in the fasted state and in the morning. The International Osteoporosis Foundation recommends using PINP and βCTX to assess bone formation and bone resorption, respectively [ 24 ].

The utility of bone turnover markers in assessing the risk of fracture has been studied in postmenopausal women. In the OFLEY cohort, healthy postmenopausal women who had BTMs in the highest quartile were noted to have a two-fold increase in the risk of fractures with a RR of 1.

In another cohort of older postmenopausal women, high levels of osteocalcin bone formation marker were associated with a higher risk of fractures [ 50 ].

BTMs can also be used for monitoring osteoporosis treatment. In postmenopausal women treated with teriparatide, an increase in P1NP at three months correlated with an increase in LS BMD at 18 months [ 52 ]. While there has been widespread use of these markers for monitoring therapy in osteoporosis, treatment goals based on fracture reduction have not been defined.

Antiresorptive and anabolic therapies increase spine and hip BMD, with the highest increases in the spine Table 1. As newer agents are studied, a trend in more efficacious BMD improvement with each new agent is apparent.

Although many osteoporosis treatments have not been directly compared in head-to-head trials, the mechanisms of actions of these newer treatments often predict a superior efficacy in increasing BMD.

All approved osteoporosis medications produce significant increases in spine and hip BMD as measured by DXA. The degree of BMD increase in the spine is likely a consequence of the greater surface area of trabecular-rich vertebral bodies on which the agents act.

The efficacy of daily, weekly and monthly oral and yearly IV bisphosphonate medications are similar [ 57 , 58 , 59 , 60 , 61 ]. Compliance with oral bisphosphonates is a common factor in those patients who fail to respond to treatment [ 62 , 63 , 64 ].

Denosumab has even greater effects likely owing to its enhanced ability to suppress bone resorption [ 65 ]. Teriparatide, an anabolic agent, increases spine and hip BMD [ 66 ]. Abaloparatide, another recently available anabolic agent, also markedly increases spine and hip BMD [ 67 ].

Romosozumab, not yet approved for treatment, is a humanized monoclonal antibody that targets sclerostin, and has been reported to increase spine BMD approximately Numerous published studies have reported the architectural changes in the skeleton with such agents using a variety of techniques that include HR-pQCT and QCT of in situ hip and spine as well as similar techniques of iliac crest bone biopsy samples.

What has become clear is that they do not uniformly produce similar results Table 1 , Fig. Bisphosphonates increase cortical thickness primarily by decreasing the endosteal perimeter, partially through the filling in of previously excavated resorption pits at the endosteal surfaces.

In addition, bisphosphonates also reduce cortical porosity and increase the amount of trabecular bone. Denosumab has similar effects and presumably to a higher degree owing to its improved fracture reduction compared to bisphosphonates. Structural changes in bone with osteoporosis medications. The anti-resorptive medications bisphosphonates and denosumab and anabolic medications teriparatide and likely abaloparatide produce very different structural changes in bone.

Although both classes increase trabecular bone, their effects on cortical bone are different. Bisphosphonates and denosumab do not expand periosteal bone but do decrease the endosteal diameter by an increase in endosteal bone volume.

Anti-resorptives also reduce cortical porosity. Anabolic agents lead to an increase in periosteal bone with a simultaneous increase in endosteal bone resorption resulting in a bone without a large change in cortical thickness.

At the same time, anabolic agents increase cortical porosity. Despite the increase in cortical porosity, the larger bone has increased strength.

Teriparatide has unusual effects on cortical bone. While spine and hip BMD increased with this agent, forearm BMD declined prompting a closer inspection of architectural changes in cortical-rich areas [ 66 ]. Teriparatide increases cortical porosity through two not mutually exclusive mechanisms: 1 increased osteocyte-directed bone resorption and 2 enhanced cortical periosteal bone expansion that leaves a larger proportion of under-mineralized bone [ 70 , 71 , 72 ].

Furthermore, since the denominator in the BMD calculation is bone area and teriparatide certainly causes an increase in periosteal diameter compared to BMC, BMD expectedly decreases. Presumably abaloparatide has similar effects but such detailed human architectural analyses have not been published.

Romosozumab is reported to increase cortical thickness and trabecular bone volume, but how this agent affects cortical porosity and bone size has not been published.

Goal-directed treatment for osteoporosis has been advocated as a superior strategy rather than treatment decisions made solely on DXA T-scores [ 73 ]. Rather than arbitrary recommendations to treat osteoporosis for 5 or 10 years with oral bisphosphonates or 3 to 6 years with IV bisphosphonates, depending on T-scores or whether a patient is deemed either low or high risk for fracture, treatment length should ideally be based on achieving a particular fracture risk threshold [ 74 ].

The FRAX risk stratification system has raised awareness among clinicians that other strong risk factors for fracture exist other than DXA T-scores—age, previous fragility fracture, high fall risk, long-term glucocorticoid use and other diseases associated with high fracture risk that include diabetes mellitus.

However, neither bone size nor architectural makeup is routinely measured but clearly have large impacts on bone strength.

For example, the femoral neck of two individuals could have the same BMD but the structure of these could be vastly different owing to the differences in size with a smaller femoral neck possessing lower strength. The bone area is already routinely reported in DXA scans but is not routinely utilized to assess risk.

However, recent data support that bone size is dynamic and that postmenopausal women with smaller femoral neck size may in fact be at lower risk for fracture as they age compared to women with larger femoral neck size due to adapted changes with aging [ 32 ].

How these inter-individual differences in the age-changes of structure and mass affect bone strength and fracture has yet to be fully determined. New imaging techniques that not only measure BMD but also measure critical indices directly related to fracture risk such as bone size, porosity, cortical thickness, trabecular volume and the mineral to matrix ratio are needed.

Even better, having such a device that is affordable and appropriately sized allowing clinicians to assess fracture risk in the clinic is the future of osteoporosis care. Until the radiation dose of QCT is lower, such imaging modalities are not practical for routine screening and treatment monitoring.

Methods to directly measure bone quality such as reference point indentation are investigative. This method is limited by pain, differing outcome measures amongst cohorts [ 75 , 76 , 77 ] and are inconsistently related to traditional tissue-level mechanical properties [ 78 , 79 ].

Compact ultrasound imaging devices that measure forearm cortical bone size and trabecular bone density is an exciting new area [ 80 ]. With advancing imaging methods, we can envision a treatment strategy whereby osteoporosis medications are selected based on individual skeletal characteristics.

For example, patients with larger bones, and thinner and porous cortices may benefit from bisphosphonates and denosumab, to reduce endocortical resorption that would ultimately increase cortical thickness.

Conversely in patients with smaller bones whose cortex is not especially porous, teriparatide or abaloparatide may provide maximal bone strength. Clearly, this is an area of further research. The challenges to wider clinical utilization of biomechanical traits in treatment decisions involve 1 better understanding of biomechanical principles, 2 developing an appreciation of how bone strength depends on multiple traits, 3 incorporating the concept that people fracture for different biomechanical reasons, and 4 coalescing this information into a digestible outcome parameter that can be used clinically are areas where more work is needed.

Using these sophisticated technologies, clinicians will be able to select therapy that targets skeletal characteristics. While much work remains in redefining and identifying individuals at risk of fractures, updating the current system of diagnosis and generating new technologies, we inch closer to the future of osteoporosis care and personalized medicine.

What is Osteoporosis and What Causes It? Arlington: National Osteoporosis Foundation. Wahner HW, Dunn WL, Brown ML, Morin RL, Riggs BL.

Comparison of dual-energy x-ray absorptiometry and dual photon absorptiometry for bone mineral measurements of the lumbar spine. Mayo Clin Proc.

Article PubMed CAS Google Scholar. Kanis JA. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: synopsis of a WHO report. WHO study group. Osteoporos Int. Sanders KM, Nicholson GC, Watts JJ, Pasco JA, Henry MJ, Kotowicz MA, Seeman E. Half the burden of fragility fractures in the community occur in women without osteoporosis.

When is fracture prevention cost-effective? Article PubMed Google Scholar. Kanis JA, McCloskey EV, Johansson H, Oden A, Melton LJ 3rd, Khaltaev N.

A reference standard for the description of osteoporosis. Donaldson LJ, Cook A, Thomson RG. Incidence of fractures in a geographically defined population. J Epidemiol Community Health.

Article PubMed PubMed Central CAS Google Scholar. Center JR, Nguyen TV, Schneider D, Sambrook PN, Eisman JA. Mortality after all major types of osteoporotic fracture in men and women: an observational study.

Trombetti A, Herrmann F, Hoffmeyer P, Schurch MA, Bonjour JP, Rizzoli R. Survival and potential years of life lost after hip fracture in men and age-matched women. Sornay-Rendu E, Munoz F, Garnero P, Duboeuf F, Delmas PD.

Identification of osteopenic women at high risk of fracture: the OFELY study. J Bone Miner Res. Schuit SC, van der Klift M, Weel AE, de Laet CE, Burger H, Seeman E, Hofman A, Uitterlinden AG, van Leeuwen JP, Pols HA.

Fracture incidence and association with bone mineral density in elderly men and women: the Rotterdam study. Ralston SH, Uitterlinden AG. Genetics of osteoporosis. Endocr Rev. Almeida M, Laurent MR, Dubois V, Claessens F, O'Brien CA, Bouillon R, Vanderschueren D, Manolagas SC.

Estrogens and androgens in skeletal physiology and pathophysiology. Physiol Rev. Keyak JH, Skinner HB, Fleming JA. Effect of force direction on femoral fracture load for two types of loading conditions.

J Orthop Res. Singh M, Nagrath AR, Maini PS. Changes in trabecular pattern of the upper end of the femur as an index of osteoporosis. J Bone Joint Surg Am. Zebaze RM, Jones A, Knackstedt M, Maalouf G, Seeman E. Construction of the femoral neck during growth determines its strength in old age. Chen H, Zhou X, Shoumura S, Emura S, Bunai Y.

Age- and gender-dependent changes in three-dimensional microstructure of cortical and trabecular bone at the human femoral neck.

Bjornerem A, Bui QM, Ghasem-Zadeh A, Hopper JL, Zebaze R, Seeman E. Fracture risk and height: an association partly accounted for by cortical porosity of relatively thinner cortices. Shigdel R, Osima M, Ahmed LA, Joakimsen RM, Eriksen EF, Zebaze R, Bjornerem A.

Bone turnover markers are associated with higher cortical porosity, thinner cortices, and larger size of the proximal femur and non-vertebral fractures. Bjornerem A. The clinical contribution of cortical porosity to fragility fractures.

Bonekey Rep. Article PubMed PubMed Central Google Scholar. Bala Y, Zebaze R, Ghasem-Zadeh A, Atkinson EJ, Iuliano S, Peterson JM, Amin S, Bjornerem A, Melton LJ 3rd, Johansson H, et al.

Cortical porosity identifies women with osteopenia at increased risk for forearm fractures. Jepsen KJ, Silva MJ, Vashishth D, Guo XE, van der Meulen MC.

Establishing biomechanical mechanisms in mouse models: practical guidelines for systematically evaluating phenotypic changes in the diaphyses of long bones. Garnero P, Sornay-Rendu E, Duboeuf F, Delmas PD. Markers of bone turnover predict postmenopausal forearm bone loss over 4 years: the OFELY study.

Johnell O, Oden A, De Laet C, Garnero P, Delmas PD, Kanis JA. Biochemical indices of bone turnover and the assessment of fracture probability.

Vasikaran S, Eastell R, Bruyere O, Foldes AJ, Garnero P, Griesmacher A, McClung M, Morris HA, Silverman S, Trenti T, et al. Markers of bone turnover for the prediction of fracture risk and monitoring of osteoporosis treatment: a need for international reference standards.

Seeman E. Age- and menopause-related bone loss compromise cortical and trabecular microstructure. J Gerontol A Biol Sci Med Sci. Fogelman I, Blake GM. DEXA scans is an acronym for Dual Energy X-Ray Absorptiometry test. This test enables you to understand just how strong or dense the bones in your body are.

Bone density scans can help you assess the risk levels of osteoporosis. This disease causes bones to weaken and more prone to breaking.

A fast and pain-free scan, the DEXA scan is extremely effective at identifying low levels of bone density. It is, in fact much more capable at determining your bone density than a traditional x-ray.

You may need to schedule a DEXA scan at Radiology Center at Harding in Morristown, New Jersey if:. Older women are particularly at risk for developing osteoporosis. This is linked with the decline in the level of estrogen levels in the body. This causes a drop-in levels bone density.

The denser your bones are, the less probable your bones are to break. DEXA scans are incredible at determining the risk of breaking bones by understanding your bone density levels.

The challenges of diagnosing osteoporosis and the limitations of currently available tools The technologist will walk behind a wall or into the next room to activate the x-ray machine. When it is used - Bone density scan DEXA scan Contents Overview When it is used How it is performed. TBS indirectly assesses skeletal texture using DXA images and can be used to predict the risk of spine and hip fractures in women and men above the age of PubMed CAS Google Scholar Farr JN, Drake MT, Amin S, Melton LJ 3rd, McCready LK, Khosla S. Article PubMed CAS Google Scholar Macdonald HM, Nishiyama KK, Hanley DA, Boyd SK. The DXA areal BMD decreases and may result in a bone with less strength.
The Pros and Cons of DXA-What Are the Alternatives?

The official position of the International Society for Clinical Densitometry ISCD is that a patient may be tested for BMD if they have a condition that could precipitate bone loss, is going to be prescribed pharmaceuticals known to cause bone loss, or is being treated and needs to be monitored.

The ISCD states that there is no clearly understood correlation between BMD and the risk of a child's sustaining a fracture; the diagnosis of osteoporosis in children cannot be made using the basis of a densitometry criteria.

T-scores are prohibited with children and should not even appear on DXA reports. Thus, the WHO classification of osteoporosis and osteopenia in adults cannot be applied to children, but Z-scores can be used to assist diagnosis.

Some clinics may routinely carry out DXA scans on pediatric patients with conditions such as nutritional rickets , lupus , and Turner syndrome. However, it seems that DXA is still in its early days in pediatrics, and there are widely acknowledged limitations and disadvantages with DXA.

A view exists [15] that DXA scans for diagnostic purposes should not even be performed outside specialist centers, and, if a scan is done outside one of these centers, it should not be interpreted without consultation with an expert in the field. Whole-body calcium measured by DXA has been validated in adults using in-vivo neutron activation of total body calcium [16] [17] but this is not suitable for paediatric subjects and studies have been carried out on paediatric-sized animals.

DXA scans can also be used to measure total body composition and fat content with a high degree of accuracy comparable to hydrostatic weighing with a few important caveats. DXA scans have been suggested as useful tools to diagnose conditions with an abnormal fat distribution, such as familial partial lipodystrophy.

DXA uses X-rays to measure bone mineral density. The radiation dose of current DEXA systems is small, [24] as low as 0. The quality of DXA operators varies widely. DXA is not regulated like other radiation-based imaging techniques because of its low dosage.

Each US state has a different policy as to what certifications are needed to operate a DXA machine. California , for example, requires coursework and a state-run test, whereas Maryland has no requirements for DXA technicians. Many states require a training course and certificate from the International Society of Clinical Densitometry ISCD.

In Australia, regulation differs according to the applicable state or territory. For example, in Victoria, an individual performing DXA scans is required to completed a recognised course in safe use of bone mineral densitometers. The Environmental Protection Agency EPA oversees licensing of technicians, however, this is far from rigorous and regulation is non-existent.

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Diagnostic test for bone mineral density testing. For the chemical, see Dextrallorphan. Main article: Bone density § Testing. National Library of Medicine. National Osteoporosis Society. Retrieved Preventive Services Task Force. January Archived from the original on 30 May Retrieved 20 August J Clin Densitom.

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DEXA scan limitations -

Despite these limitations, DXA can remain valuable for clinical assessment providing that the sources of error are kept in mind. Inaccuracy in DXA arises because only in pixels containing no bone can soft tissue composition fat versus lean be assessed.

In those pixels containing bone, of which the torso region contains many, soft tissue composition is estimated rather than measured. Endocrine Abstracts ISSN print ISSN online © Bioscientifica Privacy policy Cookie settings.

Bioscientifica Abstracts is the gateway to a series of products that provide a permanent, citable record of abstracts for biomedical and life science conferences.

Searchable abstracts of presentations at key conferences in endocrinology. ISSN print ISSN online. Endocrine Abstracts. Prev Next. Even better, having such a device that is affordable and appropriately sized allowing clinicians to assess fracture risk in the clinic is the future of osteoporosis care.

Until the radiation dose of QCT is lower, such imaging modalities are not practical for routine screening and treatment monitoring. Methods to directly measure bone quality such as reference point indentation are investigative. This method is limited by pain, differing outcome measures amongst cohorts [ 75 , 76 , 77 ] and are inconsistently related to traditional tissue-level mechanical properties [ 78 , 79 ].

Compact ultrasound imaging devices that measure forearm cortical bone size and trabecular bone density is an exciting new area [ 80 ].

With advancing imaging methods, we can envision a treatment strategy whereby osteoporosis medications are selected based on individual skeletal characteristics.

For example, patients with larger bones, and thinner and porous cortices may benefit from bisphosphonates and denosumab, to reduce endocortical resorption that would ultimately increase cortical thickness.

Conversely in patients with smaller bones whose cortex is not especially porous, teriparatide or abaloparatide may provide maximal bone strength. Clearly, this is an area of further research. The challenges to wider clinical utilization of biomechanical traits in treatment decisions involve 1 better understanding of biomechanical principles, 2 developing an appreciation of how bone strength depends on multiple traits, 3 incorporating the concept that people fracture for different biomechanical reasons, and 4 coalescing this information into a digestible outcome parameter that can be used clinically are areas where more work is needed.

Using these sophisticated technologies, clinicians will be able to select therapy that targets skeletal characteristics. While much work remains in redefining and identifying individuals at risk of fractures, updating the current system of diagnosis and generating new technologies, we inch closer to the future of osteoporosis care and personalized medicine.

What is Osteoporosis and What Causes It? Arlington: National Osteoporosis Foundation. Wahner HW, Dunn WL, Brown ML, Morin RL, Riggs BL. Comparison of dual-energy x-ray absorptiometry and dual photon absorptiometry for bone mineral measurements of the lumbar spine.

Mayo Clin Proc. Article PubMed CAS Google Scholar. Kanis JA. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: synopsis of a WHO report. WHO study group.

Osteoporos Int. Sanders KM, Nicholson GC, Watts JJ, Pasco JA, Henry MJ, Kotowicz MA, Seeman E. Half the burden of fragility fractures in the community occur in women without osteoporosis. When is fracture prevention cost-effective? Article PubMed Google Scholar. Kanis JA, McCloskey EV, Johansson H, Oden A, Melton LJ 3rd, Khaltaev N.

A reference standard for the description of osteoporosis. Donaldson LJ, Cook A, Thomson RG. Incidence of fractures in a geographically defined population. J Epidemiol Community Health. Article PubMed PubMed Central CAS Google Scholar. Center JR, Nguyen TV, Schneider D, Sambrook PN, Eisman JA. Mortality after all major types of osteoporotic fracture in men and women: an observational study.

Trombetti A, Herrmann F, Hoffmeyer P, Schurch MA, Bonjour JP, Rizzoli R. Survival and potential years of life lost after hip fracture in men and age-matched women. Sornay-Rendu E, Munoz F, Garnero P, Duboeuf F, Delmas PD. Identification of osteopenic women at high risk of fracture: the OFELY study.

J Bone Miner Res. Schuit SC, van der Klift M, Weel AE, de Laet CE, Burger H, Seeman E, Hofman A, Uitterlinden AG, van Leeuwen JP, Pols HA. Fracture incidence and association with bone mineral density in elderly men and women: the Rotterdam study. Ralston SH, Uitterlinden AG.

Genetics of osteoporosis. Endocr Rev. Almeida M, Laurent MR, Dubois V, Claessens F, O'Brien CA, Bouillon R, Vanderschueren D, Manolagas SC. Estrogens and androgens in skeletal physiology and pathophysiology.

Physiol Rev. Keyak JH, Skinner HB, Fleming JA. Effect of force direction on femoral fracture load for two types of loading conditions. J Orthop Res. Singh M, Nagrath AR, Maini PS. Changes in trabecular pattern of the upper end of the femur as an index of osteoporosis.

J Bone Joint Surg Am. Zebaze RM, Jones A, Knackstedt M, Maalouf G, Seeman E. Construction of the femoral neck during growth determines its strength in old age. Chen H, Zhou X, Shoumura S, Emura S, Bunai Y. Age- and gender-dependent changes in three-dimensional microstructure of cortical and trabecular bone at the human femoral neck.

Bjornerem A, Bui QM, Ghasem-Zadeh A, Hopper JL, Zebaze R, Seeman E. Fracture risk and height: an association partly accounted for by cortical porosity of relatively thinner cortices. Shigdel R, Osima M, Ahmed LA, Joakimsen RM, Eriksen EF, Zebaze R, Bjornerem A. Bone turnover markers are associated with higher cortical porosity, thinner cortices, and larger size of the proximal femur and non-vertebral fractures.

Bjornerem A. The clinical contribution of cortical porosity to fragility fractures. Bonekey Rep. Article PubMed PubMed Central Google Scholar. Bala Y, Zebaze R, Ghasem-Zadeh A, Atkinson EJ, Iuliano S, Peterson JM, Amin S, Bjornerem A, Melton LJ 3rd, Johansson H, et al.

Cortical porosity identifies women with osteopenia at increased risk for forearm fractures. Jepsen KJ, Silva MJ, Vashishth D, Guo XE, van der Meulen MC.

Establishing biomechanical mechanisms in mouse models: practical guidelines for systematically evaluating phenotypic changes in the diaphyses of long bones. Garnero P, Sornay-Rendu E, Duboeuf F, Delmas PD.

Markers of bone turnover predict postmenopausal forearm bone loss over 4 years: the OFELY study. Johnell O, Oden A, De Laet C, Garnero P, Delmas PD, Kanis JA.

Biochemical indices of bone turnover and the assessment of fracture probability. Vasikaran S, Eastell R, Bruyere O, Foldes AJ, Garnero P, Griesmacher A, McClung M, Morris HA, Silverman S, Trenti T, et al. Markers of bone turnover for the prediction of fracture risk and monitoring of osteoporosis treatment: a need for international reference standards.

Seeman E. Age- and menopause-related bone loss compromise cortical and trabecular microstructure. J Gerontol A Biol Sci Med Sci. Fogelman I, Blake GM. Different approaches to bone densitometry.

J Nucl Med. PubMed CAS Google Scholar. Cauley JA. Defining ethnic and racial differences in osteoporosis and fragility fractures. Clin Orthop Relat Res. Nam HS, Kweon SS, Choi JS, Zmuda JM, Leung PC, Lui LY, Hill DD, Patrick AL, Cauley JA.

J Bone Miner Metab. Third National Health and Nutrition Examination Survery NHANES III , Bone Densitometry Manual. Carey JJ, Delaney MF. T-scores and Z-scores. Clinical Review of Bone and Mineral Metabolism. Article Google Scholar. Zemel BS, Leonard MB, Kelly A, Lappe JM, Gilsanz V, Oberfield S, Mahboubi S, Shepherd JA, Hangartner TN, Frederick MM, et al.

Height adjustment in assessing dual energy x-ray absorptiometry measurements of bone mass and density in children. J Clin Endocrinol Metab. Jepsen KJ, Kozminski A, Bigelow EM, Schlecht SH, Goulet RW, Harlow SD, Cauley JA, Karvonen-Gutierrez C.

Femoral neck external size but not aBMD predicts structural and mass changes for women transitioning through menopause.

Article PubMed CAS PubMed Central Google Scholar. Martineau P, Silva BC, Leslie WD. Utility of trabecular bone score in the evaluation of osteoporosis.

Curr Opin Endocrinol Diabetes Obes. Pothuaud L, Carceller P, Hans D. Correlations between grey-level variations in 2D projection images TBS and 3D microarchitecture: applications in the study of human trabecular bone microarchitecture.

Hans D, Goertzen AL, Krieg MA, Leslie WD. Bone microarchitecture assessed by TBS predicts osteoporotic fractures independent of bone density: the Manitoba study. Leslie WD, Johansson H, Kanis JA, Lamy O, Oden A, McCloskey EV, Hans D.

Lumbar spine texture enhances year fracture probability assessment. Leslie WD, Aubry-Rozier B, Lix LM, Morin SN, Majumdar SR, Hans D. Spine bone texture assessed by trabecular bone score TBS predicts osteoporotic fractures in men: the Manitoba bone density program.

Schousboe JT, Vo T, Taylor BC, Cawthon PM, Schwartz AV, Bauer DC, Orwoll ES, Lane NE, Barrett-Connor E, Ensrud KE. Osteoporotic fractures in men Mr OSSRG: prediction of incident major osteoporotic and hip fractures by trabecular bone score TBS and prevalent radiographic vertebral fracture in older men.

McCloskey EV, Oden A, Harvey NC, Leslie WD, Hans D, Johansson H, Barkmann R, Boutroy S, Brown J, Chapurlat R, et al. A meta-analysis of trabecular bone score in fracture risk prediction and its relationship to FRAX. McCloskey EV, Oden A, Harvey NC, Leslie WD, Hans D, Johansson H, Kanis JA.

Adjusting fracture probability by trabecular bone score. Calcif Tissue Int. Moayyeri A, Adams JE, Adler RA, Krieg MA, Hans D, Compston J, Lewiecki EM.

Quantitative ultrasound of the heel and fracture risk assessment: an updated meta-analysis. Anderson DE, Demissie S, Allaire BT, Bruno AG, Kopperdahl DL, Keaveny TM, Kiel DP, Bouxsein ML.

The associations between QCT-based vertebral bone measurements and prevalent vertebral fractures depend on the spinal locations of both bone measurement and fracture. Wang X, Sanyal A, Cawthon PM, Palermo L, Jekir M, Christensen J, Ensrud KE, Cummings SR, Orwoll E, Black DM, et al.

Prediction of new clinical vertebral fractures in elderly men using finite element analysis of CT scans. Kanis JA, Johnell O, Oden A, Johansson H, McCloskey E.

FRAX and the assessment of fracture probability in men and women from the UK. Kanis JA, Oden A, Johnell O, Johansson H, De Laet C, Brown J, Burckhardt P, Cooper C, Christiansen C, Cummings S, et al.

The use of clinical risk factors enhances the performance of BMD in the prediction of hip and osteoporotic fractures in men and women. Bolland MJ, Siu AT, Mason BH, Horne AM, Ames RW, Grey AB, Gamble GD, Reid IR.

Evaluation of the FRAX and Garvan fracture risk calculators in older women. Cass AR, Shepherd AJ, Asirot R, Mahajan M, Nizami M. Comparison of the male osteoporosis risk estimation score MORES with FRAX in identifying men at risk for osteoporosis. Ann Fam Med.

van Geel TA, Eisman JA, Geusens PP, van den Bergh JP, Center JR, Dinant GJ. The utility of absolute risk prediction using FRAX R and Garvan fracture risk calculator in daily practice.

Garnero P, Sornay-Rendu E, Claustrat B, Delmas PD. Biochemical markers of bone turnover, endogenous hormones and the risk of fractures in postmenopausal women: the OFELY study. Vergnaud P, Garnero P, Meunier PJ, Breart G, Kamihagi K, Delmas PD. Undercarboxylated osteocalcin measured with a specific immunoassay predicts hip fracture in elderly women: the EPIDOS study.

Eastell R, Vrijens B, Cahall DL, Ringe JD, Garnero P, Watts NB. Bone turnover markers and bone mineral density response with risedronate therapy: relationship with fracture risk and patient adherence. Chen P, Satterwhite JH, Licata AA, Lewiecki EM, Sipos AA, Misurski DM, Wagman RB.

Early changes in biochemical markers of bone formation predict BMD response to teriparatide in postmenopausal women with osteoporosis. Black DM, Cummings SR, Karpf DB, Cauley JA, Thompson DE, Nevitt MC, Bauer DC, Genant HK, Haskell WL, Marcus R, et al. Randomised trial of effect of alendronate on risk of fracture in women with existing vertebral fractures.

Fracture intervention trial research group. Harris ST, Watts NB, Genant HK, McKeever CD, Hangartner T, Keller M, Chesnut CH 3rd, Brown J, Eriksen EF, Hoseyni MS, et al. Effects of risedronate treatment on vertebral and nonvertebral fractures in women with postmenopausal osteoporosis: a randomized controlled trial.

Vertebral efficacy with Risedronate therapy VERT study group. Chesnut CH 3rd, Skag A, Christiansen C, Recker R, Stakkestad JA, Hoiseth A, Felsenberg D, Huss H, Gilbride J, Schimmer RC, et al.

Effects of oral ibandronate administered daily or intermittently on fracture risk in postmenopausal osteoporosis. Black DM, Delmas PD, Eastell R, Reid IR, Boonen S, Cauley JA, Cosman F, Lakatos P, Leung PC, Man Z, et al. Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis.

N Engl J Med. Rizzoli R, Greenspan SL, Bone G 3rd, Schnitzer TJ, Watts NB, Adami S, Foldes AJ, Roux C, Levine MA, Uebelhart B, et al. Two-year results of once-weekly administration of alendronate 70 mg for the treatment of postmenopausal osteoporosis.

Brown JP, Kendler DL, McClung MR, Emkey RD, Adachi JD, Bolognese MA, Li Z, Balske A, Lindsay R. The efficacy and tolerability of risedronate once a week for the treatment of postmenopausal osteoporosis.

Delmas PD, McClung MR, Zanchetta JR, Racewicz A, Roux C, Benhamou CL, Man Z, Eusebio RA, Beary JF, Burgio DE, et al. Efficacy and safety of risedronate mg once a month in the treatment of postmenopausal osteoporosis. Reginster JY, Adami S, Lakatos P, Greenwald M, Stepan JJ, Silverman SL, Christiansen C, Rowell L, Mairon N, Bonvoisin B, et al.

Efficacy and tolerability of once-monthly oral ibandronate in postmenopausal osteoporosis: 2 year results from the MOBILE study. Ann Rheum Dis. Craig SJ, Youssef PP, Vaile JH, Sullivan L, Bleasel JF. Intravenous zoledronic acid and oral alendronate in patients with a low trauma fracture: experience from an osteoporosis clinic.

Intern Med J. Siris ES, Harris ST, Rosen CJ, Barr CE, Arvesen JN, Abbott TA, Silverman S. Adherence to bisphosphonate therapy and fracture rates in osteoporotic women: relationship to vertebral and nonvertebral fractures from 2 US claims databases.

Brookhart MA, Avorn J, Katz JN, Finkelstein JS, Arnold M, Polinski JM, Patrick AR, Mogun H, Solmon DH. Gaps in treatment among users of osteoporosis medications: the dynamics of noncompliance.

Am J Med. Patrick AR, Brookhart MA, Losina E, Schousboe JT, Cadarette SM, Mogun H, Solomon DH. The complex relation between bisphosphonate adherence and fracture reduction. Cummings SR, San Martin J, McClung MR, Siris ES, Eastell R, Reid IR, Delmas P, Zoog HB, Austin M, Wang A, et al. Denosumab for prevention of fractures in postmenopausal women with osteoporosis.

Neer RM, Arnaud CD, Zanchetta JR, Prince R, Gaich GA, Reginster JY, Hodsman AB, Eriksen EF, Ish-Shalom S, Genant HK, et al. Effect of parathyroid hormone on fractures and bone mineral density in postmenopausal women with osteoporosis.

Miller PD, Hattersley G, Riis BJ, Williams GC, Lau E, Russo LA, Alexandersen P, Zerbini CA, Hu MY, Harris AG, et al. Effect of Abaloparatide vs placebo on new vertebral fractures in postmenopausal women with osteoporosis: a randomized clinical trial.

Cosman F, Crittenden DB, Adachi JD, Binkley N, Czerwinski E, Ferrari S, Hofbauer LC, Lau E, Lewiecki EM, Miyauchi A, et al. Romosozumab treatment in postmenopausal women with osteoporosis. Saag KG, Petersen J, Brandi ML, Karaplis AC, Lorentzon M, Thomas T, Maddox J, Fan M, Meisner PD, Grauer A.

Romosozumab or alendronate for fracture prevention in women with osteoporosis. Tsai JN, Nishiyama KK, Lin D, Yuan A, Lee H, Bouxsein ML, Leder BZ. Effects of Denosumab and Teriparatide transitions on bone microarchitecture and estimated strength: the DATA-switch HR-pQCT study.

Zanchetta JR, Bogado CE, Ferretti JL, Wang O, Wilson MG, Sato M, Gaich GA, Dalsky GP, Myers SL. Effects of teriparatide [recombinant human parathyroid hormone ] on cortical bone in postmenopausal women with osteoporosis.

Zebaze R, Seeman E. Cortical bone: a challenging geography. Cummings SR, Cosman F, Lewiecki EM, Schousboe JT, Bauer DC, Black DM, Brown TD, Cheung AM, Cody K, Cooper C, et al. Goal-directed treatment for osteoporosis: a progress report from the ASBMR-NOF working group on goal-directed treatment for osteoporosis.

Adler RA, El-Hajj Fuleihan G, Bauer DC, Camacho PM, Clarke BL, Clines GA, Compston JE, Drake MT, Edwards BJ, Favus MJ, et al. Managing osteoporosis in patients on long-term bisphosphonate treatment: report of a task force of the American Society for Bone and Mineral Research.

Zysset PK, Guo XE, Hoffler CE, Moore KE, Goldstein SA. Mechanical properties of human trabecular bone lamellae quantified by nanoindentation. Technol Health Care. Farr JN, Drake MT, Amin S, Melton LJ 3rd, McCready LK, Khosla S.

In vivo assessment of bone quality in postmenopausal women with type 2 diabetes. Malgo F, Hamdy NAT, Papapoulos SE, Appelman-Dijkstra NM. Bone material strength index as measured by impact microindentation is low in patients with fractures irrespective of fracture site.

Allen MR, McNerny EM, Organ JM, Wallace JM. True gold or pyrite: a review of reference point indentation for assessing bone mechanical properties in vivo.

Krege JB, Aref MW, McNerny E, Wallace JM, Organ JM, Allen MR. Reference point indentation is insufficient for detecting alterations in traditional mechanical properties of bone under common experimental conditions.

Stein EM, Rosete F, Young P, Kamanda-Kosseh M, McMahon DJ, Luo G, Kaufman JJ, Shane E, Siffert RS. Ultrasound Med Biol. Cummings SR, Black DM, Thompson DE, Applegate WB, Barrett-Connor E, Musliner TA, Palermo L, Prineas R, Rubin SM, Scott JC, et al.

Effect of alendronate on risk of fracture in women with low bone density but without vertebral fractures: results from the fracture intervention trial.

Chesnut CH, Ettinger MP, Miller PD, Baylink DJ, Emkey R, Harris ST, Wasnich RD, Watts NB, Schimmer RC, Recker RR. Ibandronate produces significant, similar antifracture efficacy in north American and European women: new clinical findings from BONE. Curr Med Res Opin.

Seeman E, Delmas PD, Hanley DA, Sellmeyer D, Cheung AM, Shane E, Kearns A, Thomas T, Boyd SK, Boutroy S, et al. Microarchitectural deterioration of cortical and trabecular bone: differing effects of denosumab and alendronate.

The difference in total absorption between the two can be used, by suitable weighting, to subtract out the absorption by soft tissue, leaving just the absorption by bone, which is related to bone density.

One type of DXA scanner uses a cerium filter with a tube voltage of 80 kV , resulting in effective photon energies of about 40 and 70 keV. The combination of dual X-ray absorptiometry and laser uses the laser to measure the thickness of the region scanned, allowing for varying proportions of lean soft tissue and adipose tissue within the soft tissue to be controlled for and improving the accuracy.

The U. Preventive Services Task Force recommends that women over the age of 65 should get a DXA scan. A person's risk can be measured using the University of Sheffield's FRAX calculator, which includes many different clinical risk factors including prior fragility fracture, use of glucocorticoids , heavy smoking, excess alcohol intake, rheumatoid arthritis, history of parental hip fracture, chronic renal and liver disease, chronic respiratory disease, long-term use of phenobarbital or phenytoin, celiac disease, inflammatory bowel disease, and other risks.

The World Health Organization has defined the following categories based on bone density in white women:. Bone densities are often given to patients as a T score or a Z score. A T score tells the patient what their bone mineral density is in comparison to a young adult of the same gender with peak bone mineral density.

A normal T score is A Z score is just a comparison of what a patient's bone mineral density is in comparison to the average bone mineral density of a male or female of their age and weight.

The WHO committee did not have enough data to create definitions for men or other ethnic groups. Special considerations are involved in the use of DXA to assess bone mass in children.

Specifically, comparing the bone mineral density of children to the reference data of adults to calculate a T-score will underestimate the BMD of children, because children have less bone mass than fully developed adults.

This would lead to an over-diagnosis of osteopenia for children. To avoid an overestimation of bone mineral deficits, BMD scores are commonly compared to reference data for the same gender and age by calculating a Z-score.

Also, there are other variables in addition to age that are suggested to confound the interpretation of BMD as measured by DXA. One important confounding variable is bone size. DXA has been shown to overestimate the bone mineral density of taller subjects and underestimate the bone mineral density of smaller subjects.

This error is due to the way by which DXA calculates BMD. In DXA, bone mineral content measured as the attenuation of the X-ray by the bones being scanned is divided by the area also measured by the machine of the site being scanned. Because DXA calculates BMD using area aBMD: areal Bone Mineral Density , it is not an accurate measurement of true bone mineral density, which is mass divided by a volume.

In order to distinguish DXA BMD from volumetric bone-mineral density, researchers sometimes refer to DXA BMD as an areal bone mineral density aBMD. The confounding effect of differences in bone size is due to the missing depth value in the calculation of bone mineral density.

Despite DXA technology's problems with estimating volume, it is still a fairly accurate measure of bone mineral content. Methods to correct for this shortcoming include the calculation of a volume that is approximated from the projected area measure by DXA.

DXA BMD results adjusted in this manner are referred to as the bone mineral apparent density BMAD and are a ratio of the bone mineral content versus a cuboidal estimation of the volume of bone.

Like the results for aBMD, BMAD results do not accurately represent true bone mineral density, since they use approximations of the bone's volume. BMAD is used primarily for research purposes and is not yet used in clinical settings. Other imaging technologies such as quantitative computed tomography QCT are capable of measuring the bone's volume, and are, therefore, not susceptible to the confounding effect of bone-size in the way that DXA results are susceptible.

It is important for patients to get repeat BMD measurements done on the same machine each time, or at least a machine from the same manufacturer. Error between machines, or trying to convert measurements from one manufacturer's standard to another can introduce errors large enough to wipe out the sensitivity of the measurements.

DXA results need to be adjusted if the patient is taking strontium supplements. DXA can also used to measure trabecular bone score. DXA is, by far, the most widely used technique for bone mineral density measurements, since it is considered to be cheap, accessible, easy to use, and able to provide an accurate estimation of bone mineral density in adults.

The official position of the International Society for Clinical Densitometry ISCD is that a patient may be tested for BMD if they have a condition that could precipitate bone loss, is going to be prescribed pharmaceuticals known to cause bone loss, or is being treated and needs to be monitored.

The ISCD states that there is no clearly understood correlation between BMD and the risk of a child's sustaining a fracture; the diagnosis of osteoporosis in children cannot be made using the basis of a densitometry criteria. T-scores are prohibited with children and should not even appear on DXA reports.

Thus, the WHO classification of osteoporosis and osteopenia in adults cannot be applied to children, but Z-scores can be used to assist diagnosis. Some clinics may routinely carry out DXA scans on pediatric patients with conditions such as nutritional rickets , lupus , and Turner syndrome.

However, it seems that DXA is still in its early days in pediatrics, and there are widely acknowledged limitations and disadvantages with DXA. A view exists [15] that DXA scans for diagnostic purposes should not even be performed outside specialist centers, and, if a scan is done outside one of these centers, it should not be interpreted without consultation with an expert in the field.

Whole-body calcium measured by DXA has been validated in adults using in-vivo neutron activation of total body calcium [16] [17] but this is not suitable for paediatric subjects and studies have been carried out on paediatric-sized animals.

DXA scans can also be used to measure total body composition and fat content with a high degree of accuracy comparable to hydrostatic weighing with a few important caveats.

Goji Berry Health Products Applied Physiology Workshop 1 Healthy alternatives to sugar consumption abstracts. Scann is increasing interest in clinical assessment limitatios body Healthy alternatives to sugar consumption, however uncertainty Pimitations regarding the appropriate techniques. Dual energy X-ray absorptiometry DXA is often described as a gold standard, Glutathione and gut health view of its high precision reproducibility. However, for the limifations model of body composition limitatlons the body into water, fat, protein and mineral the in vivo gold standard comprises the multi-component model, and recent comparisons of DXA against the four-component model have revealed wide limits of agreement between the techniques, as well as variable bias inaccuracy of DXA in relation to body size, gender and adiposity. DXA is therefore no gold standard for body composition, and has limitations both for case–control studies and for longitudinal investigations. Despite these limitations, DXA can remain valuable for clinical assessment providing that the sources of error are kept in mind. Inaccuracy in DXA arises because only in pixels containing no bone can soft tissue composition fat versus lean be assessed.

Author: Nelkis

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