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

Imaging in osteogenesis imperfecta: Where we are and where we are going

Osteogenesis imperfecta (OI) is a rare phenotypically and genetically heterogeneous group of inherited skeletal dysplasias. The hallmark features of OI include bone fragility and susceptibility to fractures, bone deformity, and diminished growth, along with a plethora of associated secondary features (both skeletal and extraskeletal). The diagnosis of OI is currently made on clinical grounds and may be confirmed by genetic testing. However, imaging remains pivotal in the evaluation of this disease. The aim of this article is to review the current role played by the various radiologic techniques in the diagnosis and monitoring of OI in the postnatal setting as well as to discuss recent advances and future perspectives in OI imaging. Conventional Radiography and Dual-energy X-ray Absorptiometry (DXA) are currently the two most used imaging modalities in OI. The cardinal radiographic features of OI include generalized osteopenia/osteoporosis, bone deformities, and fractures. DXA is currently the most available technique to assess Bone Mineral Density (BMD), specifically areal BMD (aBMD). However, DXA has important limitations and cannot fully characterize bone fragility in OI based on aBMD. Novel DXA-derived parameters, such as Trabecular Bone Score (TBS), may provide further insight into skeletal changes induced by OI, but evidence is still limited. Techniques like Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) can be useful as problem-solvers or in specific settings, including the evaluation of cranio-cervical abnormalities. Recent evidence supports the use of High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) as a promising tool to improve the characterization of bone fragility in OI. However, HR-pQCT remains a primarily research technique at present. Quantitative Computed Tomography (QCT) is an alternative to DXA for the determination of BMD at central sites, with distinct advantages but considerably higher radiation exposure. Quantitative Ultrasound (QUS) is a portable, inexpensive, and radiation-free modality that may complement DXA evaluation, providing information on bone quality. However, evidence of usefulness of QUS in OI is poor. Radiofrequency Echographic Multi Spectrometry (REMS) is an emerging non-ionizing imaging method that holds promise for the diagnosis of low BMD and for the prediction of fracture risk, but so far only one published study has investigated its role in OI. To conclude, several different radiologic techniques have proven to be effective in the diagnosis and monitoring of OI, each with their own specificities and peculiarities. Clinicians should be aware of the strategic role of the various modalities in the different phases of the patient care process. In this scenario, the development of international guidelines including recommendations on the role of imaging in the diagnosis and monitoring of OI, accompanied by continuous active research in the field, could significantly improve the standardization of patient care.

Bone health status evaluation in men by means of REMS technology

BACKGROUND

Osteoporosis in males is largely under-diagnosed and under-treated, with most of the diagnosis confirmed only after an osteoporotic fracture. Therefore, there is an urgent need for highly accurate and precise technologies capable of identifying osteoporosis earlier, thereby avoiding complications from fragility fractures.

AIMS

This study aimed to evaluate the diagnostic accuracy and precision of the non-ionizing technology Radiofrequency Echographic Multi Spectrometry (REMS) for the diagnosis of osteoporosis in a male population in comparison with conventional Dual-energy X-ray Absorptiometry (DXA).

METHODS

A cohort of 603 Caucasian males aged between 30 and 90 years were involved in the study. All the enrolled patients underwent lumbar and femoral scans with both DXA and REMS. The diagnostic agreement between REMS and DXA-measured BMD was expressed by Pearson correlation coefficient and Bland-Altman method. The accuracy of the diagnostic classification was evaluated by the assessment of sensitivity and specificity considering DXA as reference.

RESULTS

A significant correlation between REMS- and DXA-measured T-score values (r = 0.91, p < 0.0001) for lumbar spine and for femoral neck (r = 0.90, p < 0.0001) documented the substantial equivalence of the two measurement techniques. Bland-Altman outcomes showed that the average difference in T-score measurement is very close to zero (-0.06 ± 0.60 g/cm2 for lumbar spine and - 0.07 ± 0.44 g/cm2 for femoral neck) confirming the agreement between the two techniques. Furthermore, REMS resulted an effective technique to discriminate osteoporotic patients from the non-osteoporotic ones on both lumbar spine (sensitivity = 90.1%, specificity = 93.6%) and femoral neck (sensitivity = 90.9%, specificity = 94.6%). Precision yielded RMS-CV = 0.40% for spine and RMS-CV = 0.34% for femur.

CONCLUSION

REMS, is a reliable technology for the diagnosis of osteoporosis also in men. This evidence corroborates its high diagnostic performance already observed in previous studies involving female populations.

In Vivo Assessment of Bone Quality Without X-rays

PURPOSE OF REVIEW

This review summarizes recent advances in the assessment of bone quality using non-X-ray techniques.

RECENT FINDINGS

Quantitative ultrasound (QUS) provides multiple measurements of bone characteristics based on the propagation of sound through bone, the attenuation of that sound, and different processing techniques. QUS parameters and model predictions based on backscattered signals can discriminate non-fracture from fracture cases with accuracy comparable to standard bone mineral density (BMD). With advances in magnetic resonance imaging (MRI), bound water and pore water, or a porosity index, can be quantified in several long bones in vivo. Since such imaging-derived measurements correlate with the fracture resistance of bone, they potentially provide new BMD-independent predictors of fracture risk. While numerous measurements of mineral, organic matrix, and bound water by Raman spectroscopy correlate with the strength and toughness of cortical bone, the clinical assessment of person's bone quality using spatially offset Raman spectroscopy (SORS) requires advanced spectral processing techniques that minimize contaminating signals from fat, skin, and blood. Limiting exposure of patients to ionizing radiation, QUS, MRI, and SORS has the potential to improve the assessment of fracture risk and track changes of new therapies that target bone matrix and micro-structure.

Effect of the body mass index, basal metabolic rate, and body fat on the radiofrequency echographic multi-spectrometry (REMS)-based bone mineral density and fracture risk: a cross-sectional study

Radiofrequency echographic multi-spectrometry (REMS) is a method to assess bone mineral density (BMD) of the axial skeleton, fragility score (FS), body mass index (BMI), basal metabolic rate (BMR), and body fat (BF) in %. The aim of the study was to investigate the influence of the BMI, BMR, and BF on the BMD and fracture risk with REMS. We conducted a cross-sectional study among 313 women, aged 20-90 years who underwent a screening for osteoporosis with REMS. Kruskal-Wallis was used to analyze the differences in BMI, BMR, and BF between the groups according to the BMD: normal BMD, osteopenia and osteoporosis and differences in the FS, fracture risk assessment (FRAX) for major osteoporotic fractures and for hip fractures (HF) according to the BMI groups: underweight, normal weight, overweight, obese, and extreme obese. Linear regression was used to assess the correlations BMI-BMD, BMR-BMD, and BF-BMD. BMI, BMR, and BF differed significantly between the groups according to the BMD (p < 0.001, p = 0.028, and p < 0.001, respectively). BMR showed high positive correlation to BMD (R = 0.765) with 95% confidence interval (CI) [0.715, 0.807] and significance of p < 0.001. BMI correlated significantly to BMD (p < 0.001), the correlation was low positive (R = 0.362) with 95% CI [0.262, 0.455]. In the BMI groups, there was significant difference in FRAX for HF and FS with p value 0.014 and < 0.001, respectively. Subjects with low BMI, BMR, and BF are at high risk for osteoporosis. Underweight women show significantly high fracture risk, assessed with FRAX and FS.

An observational study of the radiofrequency echographic multi-spectrometry (REMS)-based fragility score of the lumbar spine and total fracture risk at 5 years in women

A novel fragility score (FS) parameter, obtained during radiofrequency echographic multi-spectrometry (REMS), was developed to estimate the ultrasound-based skeletal fragility. The aim of our study is to assess the REMS-based FS of the lumbar spine (LS) among the Bulgarian women and to compare their characteristics acquired with REMS between fracture risk classes corresponding to a total fracture risk at 5 years for major osteoporotic fractures (MOF). A total of 100 Bulgarian women, who underwent a screening for osteoporotic fracture risk using the REMS technology, were included in a prospective observational study. The mean age was 60 years (years) ± 13.9 standard deviations. We assessed the FS of the LS and for each subject. The fracture risk class (R1-R7) was identified using a table combining measured REMS T score and FS values. The mean FS was 36.9 ± 17.4 SD (range: 18.5-84.3). Twelve subjects (12%) were classified into the R6 group, twenty-three (23%) into the R5, sixty-one (61%) into R4, and four (4%) into R3. Statistical analysis showed significant difference in age, height, BMD, T score, Z score, age of menopause, FRAX for MOF, and FRAX for hip fractures between the risk class groups. This is the first study which showed the REMS-based FS of the lumbar spine among the Bulgarian women. T score alone is not a good predictor of fractures. Our study showed that its use in combination with the fragility score obtained during REMS offers a robust assessment of the fracture risk at 5 years for MOF.

A Case Showing a New Diagnostic Aspect of the Application of Radiofrequency Echographic Multi-Spectrometry (REMS)

Radiofrequency echographic multi-spectrometry (REMS) is an ultrasound technique that has been recently introduced in the medical field to detect osteoporosis and fracture risk at axial sites. The use of sonography to visualize the region of interest (ROI) of the hip neck provides the opportunity to identify occult fractures. A 91-year-old woman with persistent right leg pain was referred to rheumatologist due to a known history of arthritis and osteoporosis. She was able to walk using a crutch, although experiencing an antalgic gait. The patient had recently fallen on her right side from standing height. During the visualization of the ROI of the right femoral neck using REMS, an abrupt break of the femoral cortex suspected to be a fracture was seen; therefore, the measurement of the femoral neck was performed on the left side. The T-score had value of -2.9 SD and the fragility score was 86.7. Due to unclear signs of a fracture after an X-ray of the hip, a computed tomography (CT) exam of the hip was performed, which revealed a femoral neck fracture. Occult fractures of the femoral neck are challenging to diagnose and require numerous radiologic exams. The use of ultrasound as a method to measure bone density allows the simultaneous diagnosis of osteoporosis and detection of fractures.

Radiofrequency Echographic Multispectrometry (REMS): A New Option in the Assessment Bone Status in Adults with Osteogenesis Imperfecta

This study aimed to estimate the utility of the Radiofrequency Echographic Multispectrometry (REMS) approach in the assessment of bone mineral density (BMD) in subjects with osteogenesis imperfecta (OI). In 41 subjects (40.5 ± 18.7 years) with OI and in 36 healthy controls, we measured BMD at the lumbar spine (LS-BMD), femoral neck (FN-BMD) and total hip (TH-BMD), employing a dual-energy X-ray absorptiometry tool. Additionally, REMS scans were also performed at the lumbar and femoral sites. The presence and number of reported fractures were assessed in the study population. Patients characterized by a history of fragility fractures represented 84.5% of the study population. OI subjects showed significantly reduced BMD values both at the level of the lumbar spine and the femoral subregions (p < 0.01) compared to healthy controls when performed using both the DXA and the REMS method. Dividing OI patients on the basis of the Sillence classification, no differences were found between the LS-BMD values carried out using the DXA technique between the OI type I group and OI Type III and IV groups. On the contrary, the OI Type III and IV groups presented significantly lower values of both Trabecular Bone Score (TBS) and LS-BMD through REMS with respect to OI type I patients (p < 0.05). Based on the data of this study, it is possible to conclude that even the new REMS assessment, which does not use ionizing radiation, represents an excellent method for studying the bone status in subjects affected by OI.

Radiofrequency Echographic Multi Spectrometry (R.E.M.S.): New Frontiers for Ultrasound Use in the Assessment of Bone Status-A Current Picture

Osteoporosis is a frequently occurring skeletal disease, and osteoporosis-related fractures represent a significant burden for healthcare systems. Dual-Energy X-ray Absorptiometry (DXA) is the most commonly used method for assessing bone mineral density (BMD). Today, particular attention is being directed towards new technologies, especially those that do not use radiation, for the early diagnosis of altered bone status. Radiofrequency Echographic Multi Spectrometry (REMS) is a non-ionizing technology that evaluates the bone status at axial skeletal sites by analyzing raw ultrasound signals. In this review, we evaluated the data on the REMS technique present in the literature. The literature data confirmed diagnostic concordance between BMD values obtained using DXA and REMS. Furthermore, REMS has adequate precision and repeatability characteristics, is able to predict the risk of fragility fractures, and may be able to overcome some of the limitations of DXA. In conclusion, REMS could become the method of choice for the assessment of bone status in children, in women of childbearing age or who are pregnant, and in several secondary osteoporosis conditions due to its good precision and replicability, its transportability, and the absence of ionizing radiation. Finally, REMS may allow qualitative and not just quantitative assessments of bone status.