REMS (Radiofrequency Echographic Multi-Spectrometry) is a radiation-free ultrasound-based technology, marketed under the brand name Echolight, that measures bone mineral density (BMD) and estimates fracture risk. While it offers genuine advantages, no radiation, portability, and a proprietary fragility score, a 2026 study published in Osteoporosis International found that over 90% of REMS-BMD output variance was explained by the patient’s age and weight alone.
DEXA remains the clinical gold standard for osteoporosis diagnosis and treatment decisions, and the majority of physicians will not prescribe treatment based on REMS results.
Below, I’ll walk you through what REMS is, how it compares to DEXA, what the latest research shows, and what you should do if you’ve already had a REMS scan.
My Position on REMS Bone Scan
Many of my readers and clients have asked me about REMS, whether they should get a scan, whether it’s better than a DEXA, and whether I recommend it. In this post, I try to give you a balanced and impartial analysis of the technology based on the latest research and my own clinical experience.
While I see valid applications for REMS, particularly in situations where a DEXA is unavailable or unreliable, the reality is that most of you already have access to a DEXA. It remains the gold standard used by the vast majority of clinicians, it provides image detail showing the actual state of your bones, and it is the most reliable way to monitor your bone health over time. A REMS reading does not provide insights beyond what a DEXA offers, and having two sets of results from two different technologies can create more confusion than clarity. As a clinician, I do not use REMS in my practice. The DEXA allows me to see the status of your bone in image form, identify compression fractures that might otherwise go undetected, and track meaningful changes from one scan to the next. That is the foundation I need to build a treatment plan I can stand behind.
What Is a REMS Bone Scan?
REMS stands for Radiofrequency Echographic Multi-Spectrometry. It is an ultrasound-based bone assessment technology developed by Echolight S.p.A., an Italian medical device company, and marketed in North America by Echolight Medical. The device received FDA 510(k) clearance in the United States.
During a REMS scan, a technician places an ultrasound probe on your abdomen (to scan the lumbar spine) and over each hip (to scan the femoral neck), similar sites to a standard DEXA scan. The device analyzes the backscattered ultrasound signals and compares them against a proprietary reference database. The process takes just a few minutes per site, requires no special preparation beyond fasting for several hours before the scan, and involves no radiation whatsoever.
Your REMS report will typically include:
- Bone mineral density (BMD) measured in g/cm², just like DEXA
- T-score and Z-score — comparing your BMD to a young adult reference population (T-score) and to your age-matched peers (Z-score), respectively
- Fragility Score (FS) — a proprietary number from 0 to 100, with higher values indicating greater estimated fracture risk. Echolight markets this as a measure of bone “quality” beyond density alone
What Your REMS Report Does Not Provide
What REMS does not provide is any image of your spine or hip. This is an important distinction from DEXA, which can generate a visual of your vertebral bodies.
I had a client who had a REMS scan and was excited that her bone scores were better on REMS than with her DEXA. The problem was that the REMS could not provide an image of her lumbar spine showing her compression fractures. Spine scores always appear better when compression fractures are present, because the compressed bone is denser. Without an image, this was invisible on her REMS report.
REMS Algorithm
Behind the scenes, REMS uses a two-step algorithmic process.
- First, it compares the ultrasound spectra from your scan against a set of reference models that have been selected based on your demographics, including age, sex, ethnicity, and body mass index (BMI).
- Second, it converts the resulting “osteoporosis score” into a BMD value using a separate equation that is also dependent on your age and weight. This two-layer demographic stratification is an intentional design feature, but as we’ll see below, recent research has raised significant questions about how much the ultrasound signal itself actually contributes to the final number.
REMS vs. DEXA: How Do They Compare?
If you’re researching bone density testing options, the comparison between REMS and DEXA is probably your most pressing question. Here’s an honest side-by-side look.
One important point: DEXA comes with its own well-documented limitations. Degenerative changes in the spine, bone spurs, and even aortic calcification can falsely elevate lumbar spine DEXA scores. Operator positioning matters. But DEXA’s physics are transparent and well understood, the BMD value it produces does not change if you enter a different age or weight into the system. As we’ll see next, the same cannot be said for REMS.
The majority of endocrinologists and general practitioners will not treat your osteoporosis based on your REMS result. The DEXA is considered the gold standard. That doesn’t mean REMS has no value, but it’s important that you know this before spending $300–$400 out of pocket.
What New Research Reveals About How REMS Works
Two recent studies published in Osteoporosis International have raised important questions about what REMS is actually measuring. If you use or are considering REMS, you should understand these findings.
The Chan et al. Study (March 2026)
Researchers from the University of Sydney and the Medical College of Wisconsin studied 209 patients (178 women, 31 men) who underwent REMS scans at the lumbar spine and femoral neck. They also conducted a controlled experiment with five healthy volunteers where they deliberately changed the demographic information entered into the REMS machine, while scanning the same person’s same hip.
The results were striking:
- Age and weight alone explained over 90% of the variance in REMS-BMD. To put that in perspective, when researchers built a simple formula using nothing but the patient’s age and weight, that formula alone could predict more than 90% of the REMS bone density result and more than 95% of the femoral neck fragility score. That leaves very little of the result that could be coming from the actual ultrasound measurement of your bone. By comparison, when the same kind of formula is applied to DEXA, age and body composition only predict about 20–50% of the result, the remaining 50–80% reflects real differences between one person’s skeleton and another’s. That gap is what makes DEXA clinically useful for individual patients.
- Artificially increasing the input age by 10 years caused REMS-BMD to drop by about 6.3%, even though the person’s actual bone had not changed at all.
- Artificially increasing the input weight by 5 kg caused REMS-BMD to rise by about 4.3%, again, with no change in the person’s actual bone.
- Left and right hip REMS-BMD values showed an almost perfect correlation (r = 0.99). While your left and right hips should be similar, a nearly identical reading is biologically implausible. DEXA studies typically find correlations of 0.90–0.93 between sides, because your hips aren’t perfectly symmetrical. The near-perfect REMS match suggests the shared demographic inputs are driving the result more than independent skeletal measurement at each hip.
The Bobelyak et al. Study (2025)
An earlier study by Bobelyak and colleagues found similar concerns. Their model using only age, sex, and BMI accounted for approximately 90% of the variability in femoral neck REMS-BMD. Perhaps most provocatively, they reported that REMS showed only minimal change in hip BMD values after a patient had a metallic hip prosthesis inserted, a scenario in which any device truly measuring bone should show a dramatic change.
What This Means in Plain Language
The researchers are not saying REMS is fraudulent or useless. Population-level studies do show that REMS correlates well with DEXA, and that is expected, because both age and weight genuinely correlate with bone density in the general population.
What the research suggests is that REMS may function more like a sophisticated demographic prediction of what your DEXA BMD should be for someone of your age, weight, and sex, rather than a direct, independent measurement of your individual skeleton. The ultrasound signal may play a smaller role in the final output than previously understood.
Key Takeaway
If REMS is largely telling you what your bone density probably is based on your demographics, then it’s most useful when you’re close to average for your age group, and least reliable precisely when you need it most: when your bones are significantly better or worse than expected.
The REMS Echolight Response and What to Make of It
These findings have not gone unchallenged. In December 2025, a group of 38 researchers and clinicians, many with ties to the REMS scientific community, published a formal rebuttal letter in Osteoporosis International contesting the Bobelyak study. A separate response was also issued by the International Institute of Musculoskeletal Health Education (IIMHE), a UK-based organization partnered with a REMS distributor. Their counterarguments deserve fair consideration.
The probe-placement argument.
The most substantive critique concerns Bobelyak’s hip prosthesis experiment specifically. The rebuttal authors argue that the post-surgery REMS scan images show the ultrasound probe was incorrectly positioned, scanning the trochanter (the bony prominence at the top of the thigh) rather than the femoral neck, which had been surgically replaced. If the probe missed the prosthesis entirely and instead read residual natural bone in the trochanter region, that would explain why REMS-BMD barely changed after surgery. The Echolight user manual explicitly states that scanning should not be performed on a prosthesis-bearing hip. This is a legitimate methodological concern for that particular experiment.
The “garbage in, garbage out” argument.
The rebuttal also argues that entering deliberately wrong demographic data, as both study teams did, simply causes the software to select the wrong reference population, producing predictably wrong results. They frame this as expected behaviour for any system that uses reference databases, not as evidence that demographics drive the output.
The “DEXA does it too” argument.
Finally, the rebuttal cites published studies showing that mathematical models based solely on age, sex, and body composition can predict DEXA-BMD with correlation levels comparable to those reported for REMS. Their point: if demographic-only formulas can also approximate DEXA results, then the fact that a similar formula closely predicts REMS results doesn’t prove REMS is merely a demographic calculation.
What the rebuttal does not address.
It is important to understand what these counterarguments leave unanswered. The probe-placement critique applies specifically to Bobelyak’s hip prosthesis experiment. But the Chan et al. 2026 study found the same result, demographics explaining over 90% of the REMS output, using a standard group of 209 patients with no prostheses, no altered inputs, and operators trained by Echolight’s own distributor. Chan’s team also conducted their own separate experimental manipulation with five healthy volunteers, and their operators were trained by the local Echolight distributor using standard manufacturer protocols. The rebuttal letter does not address the Chan et al. findings directly.
There is also an important distinction buried in the “DEXA does it too” argument.
Yes, demographic models can approximate DEXA-BMD at a population level, but when DEXA actually measures a real patient, the demographics explain only 20–50% of the result. The remaining 50–80% reflects genuine skeletal differences between individuals. That is what makes DEXA clinically useful for individual patients. The Chan et al. study found that demographics explain over 90% of the REMS result, leaving very little room for the ultrasound signal to differentiate one individual’s skeleton from another.
A note on transparency and potential conflicts of interest.
Transparency matters: the rebuttal letter’s corresponding author received honoraria from Echolight’s scientific board. Another lead signatory received speaker fees from Echolight and holds leadership positions at ESCEO, the International Osteoporosis Foundation, and the WCO Congress, all of which have received financial support from Echolight, the manufacturer of REMS. Several other co-signatories have disclosed ties to the company. The IIMHE response was published in partnership with Osteoscan UK, a REMS distributor. None of this automatically invalidates their arguments, but it is context you deserve to have.
By contrast, the Chan et al. research team’s conflict-of-interest disclosures cut in both directions. Two of the study’s four authors, Chan and Yabsley, own or operate REMS services commercially. A third author, Pocock, owns and operates a DEXA service. The fourth author declared no conflicts. This means the researchers who found that REMS outputs are heavily driven by demographics were publishing findings that work against their own commercial interests, two of them literally make their living providing the technology they are scrutinizing. This cross-interest transparency is notable, and it makes their willingness to publish these results arguably more credible, not less.
Finally, one detail from the Bobelyak study’s conflict-of-interest disclosure is worth noting: after the study was completed and submitted for publication, the Echolight distributor requested the immediate return of the device and subsequently asked the researchers to sign a declaration stating the device had been loaned solely for demonstration purposes and that the manufacturer had prohibited its use for research. The researchers declined to sign and published their findings.
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Four Concerns for Anyone Considering REMS
Based on the research findings and my clinical experience, here are four things you should understand:
1. The Risk of Missing Outliers
Because the REMS algorithm heavily weights age and weight, it tends to pull everyone’s result toward the population average. This creates a risk for what statisticians call “outliers”, people whose bone health is significantly different from what their demographics would predict.
A younger person with severe secondary osteoporosis might receive a reassuringly normal REMS score. An older person with exceptionally strong bones might receive an unnecessarily alarming one. In both cases, the algorithm’s demographic weighting may override what the ultrasound signal is actually detecting.
2. The FRAX “Double-Counting” Problem
FRAX is the most widely used fracture risk calculator in the world. It already incorporates age, sex, and BMI as inputs. If REMS-BMD is itself heavily driven by those same demographic variables, then entering a REMS-derived BMD value into FRAX may effectively count those demographics twice, disproportionately amplifying their weight in the risk estimate.
This doesn’t necessarily make the FRAX result wrong, but it could distort it, particularly for individuals who deviate from the population mean in either direction.
3. Monitoring Bone Changes Over Time
One of REMS’s most attractive selling points is that its radiation-free nature allows for more frequent monitoring. But if a 5 kg weight gain can algorithmically increase your REMS-BMD by approximately 4.3%, how do you know whether a change on your follow-up scan reflects actual bone improvement, or just a change in weight?
Similarly, REMS-BMD appears tethered to an age-based curve. As you age, your REMS score will decline along a demographically predicted trajectory regardless of what is actually happening in your skeleton.
Furthermore, there is currently no published evidence demonstrating that REMS can reliably detect a treatment response.
4. What the Fragility Score Actually Reflects
The Fragility Score is marketed as a measure of bone “quality” and microarchitecture, something beyond what BMD alone can tell you. It is one of REMS’s most appealing features.
However, the Chan et al. study found that a simple quadratic function of age alone predicted over 95% of the femoral neck Fragility Score variance and over 80% at the lumbar spine. This suggests the Fragility Score may reflect demographic weighting far more heavily than any independent assessment of bone microarchitecture.
Who Is Offering REMS Scans And Who Isn’t
REMS machines are being marketed to a wide range of practitioners, including wellness centers, chiropractors, integrative medicine providers, and even non-medical businesses. In many cases, you leave with a report in hand but no qualified clinician to help you interpret what the numbers mean for your treatment decisions.
Many people are getting a REMS scan as a “second opinion.” But REMS machines are being sold to many individuals regardless of their medical background. In those circumstances you leave with a report in hand but no one to help you interpret it. A number on a page is only useful if it leads to the right clinical action.
If you do choose to have a REMS scan, make sure the provider can explain your results in the context of your full clinical picture, your fracture history, risk factors, medications, and lifestyle. A scan result in isolation, from any technology, is not enough to guide treatment.
When Might REMS Still Be Useful?
Despite the concerns above, there are clinically meaningful situations where REMS may serve a genuine role. A 2025 practice parameters paper by Zambito and colleagues, published in Bone & Joint Open, outlines specific scenarios where REMS may be preferred, and even REMS’s critics acknowledge that some of these use cases have merit.
When DEXA is physically impractical.
REMS is portable. For patients who are bedridden, immobilized, or have limited mobility that makes transport to a fixed DEXA installation difficult, a portable device that can come to the bedside is a real advantage. The same applies in rural or underserved communities, mobile screening programs, and countries where DEXA access is limited.
When DEXA interpretation is compromised.
This is arguably where REMS has its strongest case. DEXA readings can be falsely elevated or unreliable in several common clinical scenarios: osteoarthritis and degenerative changes in the spine, spinal deformity or prior spinal fusion with hardware (rods, screws), vertebroplasty or kyphoplasty, and hip fractures treated with cannulated screws or intramedullary nails. In these situations, DEXA may give you a number, but that number may not reflect your true bone density. REMS, because it analyzes the ultrasound signal differently, may be less affected by these structural artifacts, though the demographic-weighting concern described above still applies.
An important caveat: REMS cannot assess a replaced hip (total hip arthroplasty or hemiarthroplasty), but it can assess the contralateral hip and lumbar spine.
When spine–hip discordance on DEXA creates diagnostic uncertainty.
It is not uncommon for DEXA to show significantly different T-scores at the spine and hip. When this discordance makes classification uncertain, a REMS scan at the same sites may provide additional context, though you should interpret it with the demographic-weighting limitations in mind.
When radiation should be minimized.
DEXA radiation is extremely low, comparable to one day of natural background exposure, and should not be a barrier for most people. But there are specific populations where even minimal radiation exposure warrants caution: during pregnancy or lactation, younger patients with conditions requiring ongoing monitoring (such as eating disorders or adolescent scoliosis), and oncological patients who may need frequent scanning throughout treatment.
For pre- and post-operative bone assessment.
Surgeons considering joint replacement or spinal fusion need to know whether a patient’s bone can tolerate instrumentation. REMS’s portability and radiation-free nature make it a practical option for peri-operative bone evaluation and short-term post-operative monitoring, situations where scheduling a DEXA may add logistical friction.
When patients with kidney disease need monitoring.
Patients with chronic kidney disease, those on dialysis, and transplant recipients face higher artefact risk with standard DEXA assessment. REMS may provide a more practical alternative for this population, though evidence in this specific group remains limited.
As a screening trigger.
Some patients who might never seek a DEXA are willing to get a quick, radiation-free scan at their wellness provider’s office or a community screening event. If an abnormal REMS result prompts them to follow up with their physician and get a proper DEXA, that is a net positive for their bone health.
The key is to understand that REMS is best viewed as a supplementary tool with specific, well-defined use cases, not as a wholesale replacement for DEXA when treatment decisions are at stake.
What to Do If Your REMS and DEXA Results Don’t Match
This is one of the most common questions I hear from clients, and it creates real anxiety. You had a DEXA showing osteopenia or osteoporosis, then you got a REMS scan and the numbers were different, sometimes dramatically so. Which one should you believe?
Here is my practical guidance:
Don’t compare them directly.
REMS and DEXA use fundamentally different technologies. Comparing a REMS T-score to a DEXA T-score is comparing apples to oranges. A difference between them does not necessarily mean one is wrong.
Don’t use REMS to override a DEXA result.
If your DEXA shows osteoporosis and your REMS shows osteopenia, do not use the REMS result as a reason to avoid treatment or skip follow-up. Your physician will base decisions on DEXA.
Don’t abandon treatment because the REMS results look better.
If you’re on an osteoporosis medication and your REMS suggests improvement, that is not sufficient evidence to discontinue therapy without your doctor’s agreement based on DEXA. Remember, there is currently no published evidence demonstrating that REMS can reliably detect a treatment response.
Use the same technology for monitoring.
Whether you choose DEXA or REMS, consistency is essential. You can only track meaningful changes over time by comparing results from the same machine type, ideally the same facility.
If you only have REMS results showing a problem, get a DEXA.
Before starting any osteoporosis medication based on a REMS finding, confirm with a DEXA scan.
I had a client who had a DEXA but was unhappy about the results. Instead of probing further into why her scores were so low, several years passed and she decided to get a REMS exam. The results were very different from the DEXA. During her consultation with me, she presented both results.
Unfortunately, I could not compare the two since the sources were radically different. In the end I asked her to get another DEXA so I could do a proper comparison. This is time and money that could have been better spent.
Tests That Can Tell You More About Your Bone Health
If you’re looking for more information about your bones beyond a standard DEXA, there are established, evidence-based options. In the USA both trabecular bone scores and vertebral fracture assessments are often available in centres that specialize in osteoporosis or larger city centres. Insurance coverage varies.
Trabecular Bone Score (TBS)
A TBS measurement is performed at the same time as your DEXA scan, no additional appointment or positioning required. It extracts additional data from the DEXA image to provide information about bone “quality”, specifically, the internal architecture of your vertebrae.
A high TBS score indicates a more robust internal scaffolding, more trabeculae (the tiny struts inside your bone) packed closely together. A low TBS score indicates more separation between trabeculae or fewer of them, meaning a higher risk of vertebral compression fracture. TBS values can also be incorporated into FRAX calculations to refine your fracture risk estimate.
Vertebral Fracture Assessment (VFA)
A VFA is a low-radiation lateral scan of your spine from L4 to T4 that can be performed on the same DEXA machine during the same visit. It allows your clinician to identify vertebral compression fractures, many of which occur around T6, T7, and T8 in the mid-back and are not visible on a standard DEXA scan.
This matters because many compression fractures are “silent”, they don’t always cause pain, and having one fracture is the single strongest predictor of having another. The more information you can gather about your spine, the better the treatment decisions.
Bone Turnover Markers
Bone turnover markers are blood tests that measure the rate of bone resorption (osteoclast activity, measured by CTx) and bone formation (osteoblast activity, measured by P1NP) in real time. Unlike DEXA or REMS, which give you a snapshot, bone markers tell you about the direction your bone health is heading. Unlike your bone, which takes years to show change, the bone cells themselves show change within a few months.
This means you can tell whether your exercise program, nutrition plan, or medication is actually moving the dial, without waiting two years, or longer for a follow-up DEXA.
Key Takeaway
If you want more detail about your bone health, ask your DEXA provider about adding TBS and VFA to your next scan. Both are evidence-based, guideline-supported, and provide information your physician can act on immediately. Bone turnover markers through a simple blood test add yet another layer of insight.
The Bottom Line
REMS is a creative technology with genuine appeal, especially for people who want a quick, radiation-free look at their bone health. It is not inherently bad, and you should not feel foolish if you’ve had one. But the latest research makes it clear that you should understand what it is and what it isn’t.
What it is:
A portable, radiation-free device that provides a demographic-weighted estimate of bone mineral density and fracture risk that correlates well with DEXA at a population level. It has specific, well-defined use cases, particularly when DEXA is physically impractical, when DEXA interpretation is compromised by hardware or degenerative changes, or when radiation must be avoided.
What it isn’t:
A direct, independent measurement of your individual skeleton that can reliably detect outliers, track treatment response, or replace DEXA for clinical decision-making.
If you’re serious about understanding your bone health, start with a DEXA. Ask about adding TBS and VFA. Consider bone turnover markers. And make sure you’re working with a clinician who can put all the pieces together into a plan that’s right for you.
REMS Echolight FAQs
Margaret Martin
Further Readings
References
- Chan D, Chen W, Yabsley E, Pocock N. Demographic determinants of REMS-derived BMD and fragility score. Osteoporos Int. 2026. doi:10.1007/s00198-026-07960-4
- Bobelyak M, Vaculik J, Stepan JJ. Bone mineral density assessment using radiofrequency echographic multispectrometry (REMS) in patients before and after total hip replacement. Osteoporos Int. 2025;36:2237–2244. doi:10.1007/s00198-025-07685-w
- Al-Daghri N, Brandi ML, Reginster JY, et al. Letter to the Editor [rebuttal]. Osteoporos Int. 2026;37:545–548. doi:10.1007/s00198-025-07817-2
- Bobelyak M, Vaculik J, Stepan J, Pocock N. Author response to OSIN-D-25-01882. Osteoporos Int. 2025. doi:10.1007/s00198-025-07789-3
- Zambito K, Kushchayeva Y, Bush A, et al. Proposed practice parameters for the performance of radiofrequency echographic multispectrometry (REMS) evaluations. Bone Jt Open. 2025;6:291–297. doi:10.1302/2633-1462.63.BJO-2024-0214.R1
- Fuggle NR, Reginster JY, Al-Daghri N, et al. Radiofrequency echographic multi spectrometry (REMS) in the diagnosis and management of osteoporosis: state of the art. Aging Clin Exp Res. 2024;36:135. doi:10.1007/s40520-024-02830-x
- Pisani P, Conversano F, Muratore M, et al. Fragility Score: a REMS-based indicator for the prediction of incident fragility fractures at 5 years. Aging Clin Exp Res. 2023;35:763–773.
- Di Paola M, Gatti D, Viapiana O, et al. Radiofrequency echographic multispectrometry compared with dual X-ray absorptiometry for osteoporosis diagnosis. Osteoporos Int. 2019;30:391–402.
- Blake GM, Fogelman I. Technical principles of dual energy X-ray absorptiometry. Semin Nucl Med. 1997;27:210–228.
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