DXA beyond bone mineral density and the REMS technique: new insights for current radiologists practice.

Osteoporosis is the most prevalent skeletal disorder, a condition that is associated with significant social and healthcare burden. In the elderly, osteoporosis is commonly associated with sarcopenia, further increasing the risk of fracture. Several imaging techniques are available for a non-invasive evaluation of osteoporosis and sarcopenia. This review focuses on dual-energy X-ray absorptiometry (DXA), as this technique offers the possibility to evaluate bone mineral density and body composition parameters with good precision and accuracy. DXA is also able to evaluate the amount of aortic calcification for cardiovascular risk estimation. Additionally, new DXA-based parameters have been developed in recent years to further refine fracture risk estimation, such as the Trabecular Bone Score and the Bone Strain Index. Finally, we describe the recent advances of a newly developed ultrasound-based technology known as Radiofrequency Echographic Multi-Spectrometry, which represent the latest non-ionizing approach for osteoporosis evaluation at central sites.

Radiofrequency echographic multi spectrometry (REMS) in the diagnosis and management of osteoporosis: state of the art.

Radiofrequency Echographic Multi Spectrometry (REMS) is a radiation-free, portable technology, which can be used for the assessment and monitoring of osteoporosis at the lumbar spine and femoral neck and may facilitate wider access to axial BMD measurement compared with standard dual-energy x-ray absorptiometry (DXA).There is a growing literature demonstrating a strong correlation between DXA and REMS measures of BMD and further work supporting 5-year prediction of fracture using the REMS Fragility Score, which provides a measure of bone quality (in addition to the quantitative measure of BMD).The non-ionising radiation emitted by REMS allows it to be used in previously underserved populations including pregnant women and children and may facilitate more frequent measurement of BMD.The portability of the device means that it can be deployed to measure BMD for frail patients at the bedside (avoiding the complications in transfer and positioning which can occur with DXA), in primary care, the emergency department, low-resource settings and even at home.The current evidence base supports the technology as a useful tool in the management of osteoporosis as an alternative to DXA.

Short-Term Precision and Repeatability of Radiofrequency Echographic Multi Spectrometry (REMS) on Lumbar Spine and Proximal Femur: An In Vivo Study.

To determine the short-term intra-operator precision and inter-operator repeatability of radiofrequency echographic multi-spectrometry (REMS) at the lumbar spine (LS) and proximal femur (FEM). All patients underwent an ultrasound scan of the LS and FEM. Both precision and repeatability, expressed as root-mean-square coefficient of variation (RMS-CV) and least significant change (LSC) were obtained using data from two consecutive REMS acquisitions by the same operator or two different operators, respectively. The precision was also assessed in the cohort stratified according to BMI classification. The mean (±SD) age of our subjects was 48.9 ± 6.8 for LS and 48.3 ± 6.1 for FEM. Precision was assessed on 42 subjects at LS and 37 subjects on FEM. Mean (±SD) BMI was 24.71 ± 4.2 for LS and 25.0 ± 4.84 for FEM. Respectively, the intra-operator precision error (RMS-CV) and LSC resulted in 0.47% and 1.29% at the spine and 0.32% and 0.89% at the proximal femur evaluation. The inter-operator variability investigated at the LS yielded an RMS-CV error of 0.55% and LSC of 1.52%, whereas for the FEM, the RMS-CV was 0.51% and the LSC was 1.40%. Similar values were found when subjects were divided into BMI subgroups. REMS technique provides a precise estimation of the US-BMD independent of subjects' BMI differences.

Fragility Score: a REMS-based indicator for the prediction of incident fragility fractures at 5 years.

BACKGROUND: Accurate estimation of the imminent fragility fracture risk currently represents a challenging task. The novel Fragility Score (FS) parameter, obtained during a Radiofrequency Echographic Multi Spectrometry (REMS) scan of lumbar or femoral regions, has been developed for the non-ionizing estimation of skeletal fragility. AIMS: The aim of this study was to assess the performance of FS in the early identification of patients at risk for incident fragility fractures with respect to bone mineral density (BMD) measurements. METHODS: Data from 1989 Caucasians of both genders were analysed and the incidence of fractures was assessed during a follow-up period up to 5 years. The diagnostic performance of FS to discriminate between patients with and without incident fragility fracture in comparison to that of the BMD T-scores measured by both Dual X-ray Absorptiometry (DXA) and REMS was assessed through ROC analysis. RESULTS: Concerning the prediction of generic osteoporotic fractures, FS provided AUC = 0.811 for women and AUC = 0.780 for men, which resulted in AUC = 0.715 and AUC = 0.758, respectively, when adjusted for age and body mass index (BMI). For the prediction of hip fractures, the corresponding values were AUC = 0.780 for women and AUC = 0.809 for men, which became AUC = 0.735 and AUC = 0.758, respectively, after age- and BMI-adjustment. Overall, FS showed the highest prediction ability for any considered fracture type in both genders, resulting always being significantly higher than either T-scores, whose AUC values were in the range 0.472-0.709. CONCLUSION: FS displayed a superior performance in fracture prediction, representing a valuable diagnostic tool to accurately detect a short-term fracture risk.

Cost-minimization analysis to support the HTA of Radiofrequency Echographic Multi Spectrometry (REMS) in the diagnosis of osteoporosis.

Introduction: A timely diagnosis of osteoporosis is key to reducing its growing clinical and economic burden. Radiofrequency Echographic Multi Spectrometry (REMS), a new diagnostic technology using an ultrasound approach, has been recognized by scientific associations as a facilitator of patients' care pathway. We aimed at evaluating the costs of REMS vs. the conventional ionizing technology (dual-energy X-ray absorptiometry, DXA) for the diagnosis of osteoporosis from the perspective of the Italian National Health Service (NHS) using a cost-minimization analysis (CMA). Methods: We carried out structured qualitative interviews and a structured expert elicitation exercise to estimate healthcare resource consumption with a purposeful sample of clinical experts. For the elicitation exercise, an Excel tool was developed and, for each parameter, experts were asked to provide the lowest, highest and most likely value. Estimates provided by experts were averaged with equal weights. Unit costs were retrieved using different public sources. Results: Considering the base-case scenario (most likely value), the cost of professionals amounts to €31.9 for REMS and €48.8 for DXA, the cost of instrumental examinations and laboratory tests to €45.1 for REMS and €68.2 for DXA. Overall, in terms of current costs, REMS is associated with a mean saving for the NHS of €40.0 (range: €27.6-71.5) for each patient. Conclusions: REMS is associated with lower direct healthcare costs with respect to DXA. These results may inform policy-makers on the value of the REMS technology in the earlier diagnosis for osteoporosis, and support their decision regarding the reimbursement and diffusion of the technology in the Italian NHS.

Could radiofrequency echographic multispectrometry (REMS) overcome the overestimation in BMD by dual-energy X-ray absorptiometry (DXA) at the lumbar spine?

BACKGROUND: Osteoarthritis (OA) and vertebral fractures at the lumbar spine lead to an overestimation of bone mineral density (BMD). Recently, a new approach for osteoporosis diagnosis, defined as radiofrequency echographic multi-spectrometry (REMS), represents an innovative diagnostic tool that seems to be able to investigate bone quality and provide an estimation of fracture risk independent of BMD. The aim of this paper was to evaluate whether the use of REMS technology can favor the diagnosis of osteoporosis in subjects with an apparent increase in BMD. METHODS: In a cohort of 159 postmenopausal (66.2 ± 11.6 yrs) women with overestimated BMD by DXA at the lumbar spine, we performed an echographic scan with the REMS technique. RESULTS: The mean values of BMD at different skeletal sites obtained by the DXA and REMS techniques showed that the BMD T-scores by REMS were significantly lower than those obtained by the DXA technique both at the lumbar spine (p < 0.01) and at all femoral subregions (p < 0.05). In OA subjects, the percentage of women classified as "osteoporotic" on the basis of BMD by REMS was markedly higher with respect to those classified by DXA (35.1% vs 9.3%, respectively). Similarly, the REMS allows a greater number of fractured patients to be classified as osteoporotic than DXA (58.7% vs 23.3%, respectively). CONCLUSIONS: REMS technology by the analysis of native raw unfiltered ultrasound signals appears to be able to overcome the most common artifacts, such as OA and vertebral fracture of the lumbar spine, which affect the value of BMD by DXA.

Pulse-Echo Measurements of Bone Tissues. Techniques and Clinical Results at the Spine and Femur.

The aim of this chapter is to review the available pulse-echo approaches for the quantitative evaluation of bone health status, with a specific application to the assessment of possible osteoporosis presence and to the fracture risk prediction. Along with a review of the main in-vivo imaging approaches for skeletal robustness evaluation and fracture risk assessment, further understanding into Radiofrequency Echographic Multi Spectrometry (REMS), an ultrasound-based method measuring clinically relevant bone districts (i.e. lumbar vertebrae and proximal femur), is provided, and the further potentialities of this technology are discussed.Currently, the bone mineral density (BMD) provided by dual X-ray absorptiometry (DXA) is considered an established indicator for osteoporosis status assessment and fracture risk prediction, however, in order to obtain more accurate results, an additional step beyond BMD would be necessary, which means including data on bone quality for an improved evaluation of the disease and its consequences.REMS is a technology which allows both osteoporosis diagnosis, through the BMD estimation, and the prediction of fracture risk, through the computation of the Fragility Score; both measures are obtained by the automatic processing of unfiltered ultrasound signals acquired in correspondence of anatomical reference sites.

Ability of radiofrequency echographic multispectrometry to identify osteoporosis status in elderly women with type 2 diabetes.

BACKGROUND: Patients with type 2 diabetes (T2DM) have an increased or normal BMD; however fragility fractures represent one of the most important complications of T2DM. AIMS: This study aimed to evaluate whether the use of the Radiofrequency Echographic multi spectrometry (REMS) technique may improve the identification of osteoporosis in T2DM patients. METHODS: In a cohort of 90 consecutive postmenopausal elderly (70.5 ± 7.6 years) women with T2DM and in 90 healthy controls we measured BMD at the lumbar spine (LS-BMD), at femoral neck (FN-BMD) and total hip (TH-BMD) using a dual-energy X-ray absorptiometry device; moreover, REMS scans were also carried out at the same axial sites. RESULTS: DXA measurements were all higher in T2DM than in non-T2DM women; instead, all REMS measurements were lower in T2DM than in non T2DM women. Moreover, the percentage of T2DM women classified as "osteoporotic", on the basis of BMD by REMS was markedly higher with respect to those classified by DXA (47.0% vs 28.0%, respectively). On the contrary, the percentage of T2DM women classified as osteopenic or normal by DXA was higher with respect to that by REMS (48.8% and 23.2% vs 38.6% and 14.5%, respectively). T2DM women with fragility fractures presented lower values of both BMD-LS by DXA and BMD-LS by REMS with respect to those without fractures; however, the difference was significant only for BMD-LS by REMS (p < 0.05). CONCLUSIONS: Our data suggest that REMS technology may represent a useful approach to enhance the diagnosis of osteoporosis in patients with T2DM.

New technology REMS for bone evaluation compared to DXA in adult women for the osteoporosis diagnosis: a real-life experience.

Osteoporosis is a prevalent skeletal disorder in postmenopausal women. REMS represents a potential technology for osteoporosis diagnosis in clinical practice. OBJECTIVE: To assess the accuracy of Radiofrequency Echographic Multi Spectrometry (REMS) technology in diagnosing osteoporosis in comparison with dual X-ray absorptiometry (DXA) on a population of Brazilian women. METHODS: A population of women age ranged between 30 and 80 was recruited at DXA Service of São Paulo School-Hospital, Brazil. They underwent REMS and DXA scans at the axial sites. The REMS accuracy for the osteoporosis diagnosis was evaluated in comparison with DXA on both sites. The intra-operator and inter-operator coefficient of variation (CV) was also calculated. RESULTS: A total of 343 patients were enrolled in the study. Erroneous scans due to poor quality acquisitions with both methods or to other technical reasons were excluded; 227 lumbar spine exams and 238 hip exams were acceptable for comparison analysis. The comparison between REMS and DXA outcomes showed that the average difference in BMD (expressed as bias±1.96 SD) was -0.026±0.179g/cm2 for the spine and -0.027±0.156g/cm2 for the femoral neck. When accepted 0.3 tolerance on T-score, there were no cases diagnosed as osteoporosis by DXA that were defined as normal by REMS. The REMS intra-operator CV was 0.51% for the lumbar spine and 1.08% for the femoral neck. The REMS inter-operator CV was 1.43% for the lumbar spine and 1.93% for the femoral neck. CONCLUSION: The REMS approach had high accuracy for the diagnosis of osteoporosis in comparison with DXA in adult women. According to our results, this new technology has shown to be a promising alternative for populations without access to DXA densitometry.

Could Radiofrequency Echographic Multi-Spectrometry (REMS) Overcome the Limitations of BMD by DXA Related to Artifacts? A Series of 3 Cases.

Dual-energy X-ray absorptiometry (DXA) is considered the gold standard in the evaluation of bone mineral density (BMD) and in the diagnosis of osteoporosis.The diagnostic sensitivity of BMD at lumbar spine is frequently reduced by the presence of artifacts. This study aimed to show the usefulness of radiofrequency echographic multi-spectrometry (REMS) in determining lumbar BMD in the presence of artifacts with DXA measurements. We present 3 cases in which REMS technology, by the analysis of native raw unfiltered ultrasound signals, appears to be able to recognize and overcome the most common artifacts that affect the value of the BMD by DXA, thus allowing a better assessment of fracture risk.

Radiofrequency Echographic Multi Spectrometry (REMS) for the diagnosis of osteoporosis in a European multicenter clinical context.

BACKGROUND: Radiofrequency Echographic Multi Spectrometry (REMS) is a non-ionizing technology for the densitometric assessment of osteoporosis. It has already been validated in Italian women with respect to the current clinical reference technology, Dual-energy X-ray Absorptiometry (DXA). PURPOSE: Aim of the current study was to assess the diagnostic accuracy of REMS technology with respect to DXA in a wider European clinical context. METHODS: A total of 4307 female Caucasian patients aged between 30 and 90 years underwent DXA and REMS scans at femoral neck and/or lumbar spine (the site depending on the medical prescription). The acquired data underwent a rigorous quality check in order to exclude the erroneous DXA and REMS reports. The diagnostic agreement between the two technologies was assessed, also stratifying for patients' age groups. The ability to recognise previously fractured patients was also investigated. RESULTS: Overall, 4245 lumbar spine scans and 4271 femoral neck scans were performed. The ability to discriminate patients with and without osteoporosis by femoral neck investigation resulted in sensitivity and specificity of 90.4% and 95.5%, respectively. For lumbar spine scans, a sensitivity of 90.9% and a specificity of 95.1% were obtained. The areas under the curve (AUCs) of the Receiver Operating Characteristic (ROC) curve evaluating the ability to discriminate groups of patients with previous osteoporotic fracture using DXA and REMS T-score values were 0.631 and 0.683 (p < 0.0001), respectively, for femoral neck scans, whereas 0.603 and 0.640 (p = 0.0002), respectively, for lumbar spine scans. CONCLUSION: The diagnostic effectiveness of REMS technology at reference anatomical sites for the assessment of osteoporosis has been confirmed in a large series of female patients, spanning from younger and pre-menopausal to elderly women up to 90 years, in a multicenter European clinical context.