A novel quantitative method for estimating bone mineral density using B-mode ultrasound and radiofrequency signals-a pilot study on patients with rheumatoid arthritis

Radiofrequency echographic multi-spectrometry-based measurement of bone mineral density in patients with severe motor and intellectual disability: An opportunity for patients with severe scoliosis and hip dislocation

Purpose

Radiofrequency echographic multi-spectrometry (REMS) is an ultrasound technology currently used for the densitometric evaluation of osteoporosis and has been validated against dual-energy X-ray absorptiometry. However, the use of REMS for bone densitometry in patients with severe motor and intellectual disabilities (SMID) remains to be reported. This study aimed to investigate whether REMS technology can be used for densitometric evaluation of osteoporosis in patients with SMID with hip dislocation and severe scoliosis.

Methods

Sixty-five patients with SMID, who resided in a long-term care facility and received comprehensive medical and rehabilitation care, underwent REMS scans of the femoral neck and/or lumbar spine. Data regarding anthropometric parameters (height and weight), bone mineral density (BMD), clinical diagnostic classification, physical ability, presence of scoliosis and hip dislocation, and frontal radiographs of both hip joints were obtained.

Results

We included 29 men and 34 women (mean age: 52.6 years). All patients underwent successful scanning at either the femoral neck (82.5 %) or lumbar spine (95.2 %). BMD measurements obtained using REMS revealed low values, with a mean BMD, T-score, and Z-score of 0.67 g/cm2, -2.39 standard deviation (SD), and - 1.38 SD, respectively, at the femoral neck and 0.66 g/cm2, -2.70 SD, and - 1.87 SD, respectively, at the lumbar spine. The average Cobb angle of the lumbar spine was 34.0°; furthermore, dislocation rates did not significantly differ between those with and without successful BMD measurements (p = 0.073). Lumbar BMD T-scores were significantly correlated with femoral neck BMD T-scores (p < 0.001, r = 0.530).

Conclusion

All patients with SMID were able to undergo measurements of either spinal or femoral neck BMD; furthermore, 77.7 % of the patients underwent measurements at both the lumbar spine and femur. Our data suggest that REMS is useful for measuring BMD in patients with SMID who are residing in institutions.

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.

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.

Evaluation of the bone mineral density in the Mexican female population using the Radiofrequency Echographic Multi Spectrometry (REMS) technology

The bone health status of a Mexican female population, including a cohort of 455 women aged over 40 years, was assessed by Radiofrequency Echographic Multi Spectrometry (REMS).

PURPOSE

Assessment of the bone health status in an average female Mexican population with REMS. The secondary objective investigated age- and body mass index (BMI)-related effects on the diagnostic classification and the influence of risk factors for osteoporosis.

METHODS

Women aged over 40 years underwent a REMS scan at the lumbar spine and both femoral necks. The degree of correlation of the bone mineral density (BMD) across axial sites was assessed by the Pearson correlation coefficient (r), along with the diagnostic discordance. The association between risk factors, age, and BMI and diagnostic classification was determined by the chi-squared test.

RESULTS

Four hundred seventy-one women were enrolled. Osteoporosis was diagnosed in 11.0%, 8.1%, and 8.3% of cases at the lumbar spine and right and left femoral neck, respectively. The diagnostic agreement between the lumbar spine and femoral necks was about 73% (85% considering a 0.3 T-score tolerance), whereas the agreement between the femoral necks was 97.4% (99.6% considering a 0.3 T-score tolerance). Most of discordant cases were minor discordances. The correlation between the lumbar spine and femoral neck was r = 0.82 and 0.85, respectively, whereas both femoral necks correlated with r = 0.97. As expected, the prevalence of osteoporosis increased with age and decreased as BMI increased.

CONCLUSION

The widespread applicability of the non-ionizing REMS technology has been demonstrated in a representative Mexican cohort, covering wide age and BMI ranges. Age and BMI variations correlate with the prevalence of osteoporosis, in line with the recent scientific literature.

A novel quantitative and reference-free ultrasound analysis to discriminate different concentrations of bone mineral content

Bone fracture is a continuous process, during which bone mineral matrix evolves leading to an increase in hydroxyapatite and calcium carbonate content. Currently, no gold standard methods are available for a quantitative assessment of bone fracture healing. Moreover, the available tools do not provide information on bone composition. Whereby, there is a need for objective and non-invasive methods to monitor the evolution of bone mineral content. In general, ultrasound can guarantee a quantitative characterization of tissues. However, previous studies required measurements on reference samples. In this paper we propose a novel and reference-free parameter, based on the entropy of the phase signal calculated from the backscattered data in combination with amplitude information, to also consider absorption and scattering phenomena. The proposed metric was effective in discriminating different hydroxyapatite (from 10 to 50% w/v) and calcium carbonate (from 2 to 6% w/v) concentrations in bone-mimicking phantoms without the need for reference measurements, paving the way to their translational use for the diagnosis of tissue healing. To the best of our knowledge this is the first time that the phase entropy of the backscattered ultrasound signals is exploited for monitoring changes in the mineral content of bone-like materials.