Radiofrequency Echographic Multi Spectrometry (REMS)

Dual-energy X-ray absorptiometry (DXA) remains the clinical standard for estimating bone mineral density (BMD) and diagnosing osteopenia and osteoporosis. However, because DXA relies on ionizing radiation, its use may be limited in certain populations and in situations where frequent monitoring is desirable.

Radiofrequency Echographic Multi Spectrometry (REMS) is an emerging, non-ionizing ultrasound-based technology developed to assess BMD and bone quality without radiation exposure. Rather than measuring X-ray attenuation, REMS analyzes raw ultrasound radiofrequency (RF) signals reflected from bone structures. These signals are processed in the frequency domain and compared with reference databases stratified by sex, age, and body size to generate BMD values, T-scores, and a novel parameter known as the Fragility Score, which reflects aspects of bone quality and microarchitecture beyond density alone.

Clinically, REMS examinations are typically performed at axial skeletal sites, most commonly the lumbar spine and femoral neck, using a standard ultrasound probe. Scan times are brief—usually one to two minutes—and advanced algorithms help minimize artifacts from degenerative changes or vascular calcifications that can affect DXA measurements. The result is a set of quantitative outputs that are broadly comparable to DXA-derived values.

One of the key advantages of REMS is the absence of ionizing radiation, allowing safe use in populations for whom DXA may be less suitable, including pregnant women, children, and frail or bed-bound patients. Over the past several years, validation studies have demonstrated strong correlations between REMS-derived and DXA-derived BMD measurements, along with high sensitivity and specificity for identifying osteoporosis in selected cohorts. Importantly, the REMS Fragility Score has shown promise for predicting fracture risk independentley of BMD, supporting a more comprehensive assessment of bone health.

While DXA remains the method recommended in most clinical guidelines due to its widespread availability and long-established reference standards, REMS represents a valuable complementary approach. Its portability, lack of radiation, and reduced susceptibility to certain artifacts make it particularly attractive for screening, follow-up assessments, and use in settings where DXA access is limited.

Why this matters:
REMS expands access to bone health assessment by offering a radiation-free, portable alternative that can be used more frequently and in populations where DXA is not ideal—supporting earlier detection, safer monitoring, and more individualized osteoporosis care.