Abstract

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. This study evaluates whether the use of REMS technology can favor the diagnosis of osteoporosis in subjects with an apparent increase in BMD.

Methods: A cohort of 159 postmenopausal women (66.2 ± 11.6 years) with overestimated BMD by DXA at the lumbar spine underwent echographic scans using the REMS technique.

Results: The mean values of BMD at different skeletal sites obtained by DXA and REMS showed that the BMD T-scores by REMS were significantly lower than those obtained by DXA at both the lumbar spine (p < 0.01) and at all femoral subregions (p < 0.05). In OA subjects, the percentage of women classified as “osteoporotic” based on BMD by REMS was markedly higher than those classified by DXA (35.1% vs. 9.3%, respectively). Similarly, REMS allowed a greater number of fractured patients to be classified as osteoporotic compared to DXA (58.7% vs. 23.3%, respectively).

Conclusions: REMS technology, by analyzing native raw unfiltered ultrasound signals, appears to overcome the most common artifacts such as OA and vertebral fractures that affect the value of BMD by DXA.

Keywords: Osteoporosis, Osteoarthritis, Vertebral fractures, Radiofrequency Echographic Multi-Spectrometry (REMS), Dual-Energy X-ray Absorptiometry (DXA).

Introduction

Osteoporosis and osteoarthritis (OA) are two prevalent conditions that significantly affect bone health, especially in postmenopausal women. Dual-Energy X-ray Absorptiometry (DXA) has been considered the gold standard for diagnosing osteoporosis by measuring Bone Mineral Density (BMD). However, the accuracy of DXA can be compromised by structural abnormalities such as osteophytes (bone spurs) and vertebral fractures, particularly at the lumbar spine. These conditions lead to overestimated BMD, which can result in incorrect diagnoses.

Radiofrequency Echographic Multi-Spectrometry (REMS) is a non-ionizing diagnostic technique that uses raw, unfiltered ultrasound signals to assess bone quality. REMS has shown promise in overcoming these DXA-related artifacts, providing a more accurate measure of bone health and fracture risk, especially in patients with OA and vertebral fractures.

This study evaluates whether REMS technology can improve the diagnosis of osteoporosis in patients with overestimated BMD due to these structural abnormalities.

Methods

Study Design and Participants

The study involved 159 postmenopausal women (mean age: 66.2 ± 11.6 years) with overestimated BMD by DXA at the lumbar spine. Participants were selected based on the following inclusion criteria:

• Postmenopausal status
• Radiographic evidence of OA or vertebral fractures at the lumbar spine
• Age: 50–80 years

Exclusion criteria included:

• Previous treatment with anti-osteoporosis medications (other than calcium and vitamin D)
• Conditions such as cancer, multiple myeloma, or hyperparathyroidism
• Severe obesity (BMI > 40 kg/m²)

BMD Measurement

BMD measurements were taken using both DXA and REMS:

1. DXA: BMD was measured at the lumbar spine, femoral neck, and total hip using a Hologic Discovery W DXA system.
2. REMS: BMD was measured using the Echolight EchoStation device, employing a 3.5 MHz convex transducer to analyze unfiltered ultrasound signals.

Statistical Analysis

• Descriptive statistics were used to summarize the demographic characteristics of the participants.
• The Kolmogorov–Smirnov test was used to check the normality of data distribution.
• Comparisons between DXA and REMS measurements were made using Student’s t-test and Mann–Whitney U-test where appropriate.
• Categorical variables were compared using the chi-square test or Fisher’s exact test.

Results

Table 1: Demographic and Clinical Characteristics of the Study Population

Notes:

• *p < 0.05, **p < 0.01, ***p < 0.001 fractured vs osteoarthritis subjects

BMD Comparison: DXA vs. REMS

The T-scores for BMD at the lumbar spine were significantly lower when measured by REMS compared to DXA (p < 0.01). Similar differences were observed at all femoral sites (p < 0.05).

OA and Fractured Patients: Classification as Osteoporotic

• OA patients: 35.1% were classified as osteoporotic by REMS, compared to only 9.3% by DXA.
• Fractured patients: 58.7% were classified as osteoporotic by REMS, compared to only 23.3% by DXA.

Discussion

REMS is an emerging technology that provides a more accurate assessment of osteoporosis, particularly in patients with OA and vertebral fractures, where DXA often overestimates BMD. The artifacts caused by these conditions can distort the results obtained from DXA, leading to incorrect classifications. REMS, by analyzing raw unfiltered ultrasound signals, overcomes these artifacts and gives a more reliable diagnosis.

Schematic example of the subject’s lumbar spine assessment of BMD by DXA (A) and REMS (C) in a 69-year-old woman with severe osteoarthritis at X-ray scan (B)

The ability of REMS to assess bone quality independently of BMD provides a more precise fracture risk assessment, making it particularly useful in patients where DXA’s accuracy is compromised by OA and vertebral fractures.

Values of BMD expressed as T-score at lumbar spine (LS), at femoral neck (FN) and at total hip (TH) by DXA and REMS technique in 159 postmenopausal women with fractures or osteoarthritis at lumbar spine

Values of BMD expressed as T-score at lumbar spine (LS), at femoral neck (FN) and at total hip (TH) by DXA and REMS technique in subject with fractures (A) and in subjects with osteoarthritis at lumbar spine (B)

Conclusions

This study highlights the advantages of REMS over DXA, particularly in OA and vertebral fracture patients, where DXA often fails due to artifacts. REMS provides a more accurate and reliable tool for assessing osteoporosis and fracture risk, which is especially important in these complex patient populations.

Further studies are needed to confirm the applicability of REMS as a routine diagnostic tool for osteoporosis and fracture risk assessment.