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.

First assessment of bone mineral density in healthy pregnant women by means of Radiofrequency Echographic Multi Spectrometry (REMS) technology

OBJECTIVE

The maternal bone structure is the largest calcium reserve for the fetus during pregnancy, and this is claimed to lead to a bone mineral density (BMD) reduction in pregnant women. The primary outcome of the present work was to assess the BMD in a group of healthy pregnant women.

STUDY DESIGN

In this prospective case - control observational study, a non-consecutive group of pregnant women with uncomplicated pregnancy at or >37 weeks were enrolled at the unit of Obstetrics and Gynecology, University of Parma, from February to December 2020. The study subjects were submitted to a sonographic examination of the proximal femur with Radiofrequency Echographic Multi Spectrometry (REMS) technology to quantify the BMD of the femur. The BMD values obtained in the study group were compared with those of a control group of non-pregnant women matched for age, ethnicity and pre-pregnant body mass index (BMI).

RESULTS

Overall, 78 pregnant women at 39.1 ± 1.5 weeks were assessed. Compared with non-pregnant women, the femoral BMD values measured in pregnancy using REMS were significant lower (0.769 ± 0.094 g/cm² vs 0.831 ± 0.101 g/cm², p = 0.0001) with a mean BMD reduction of 8.1%. The femoral neck BMD presented a positive correlation with the pre-pregnant BMI (p = 0.0004) and a negative correlation with the maternal age (p < 0.0001). In addition, a lower femoral neck BMD in Caucasian ethnicity compared with non-Caucasian was noted (p < 0.0001).

CONCLUSION

In this exploratory and proof of concept study, for the first time, a decreased BMD has been objectively demonstrated in pregnant compared with non-pregnant women by means of REMS technology. New studies are required to assess the longitudinal changes of maternal bone density throughout the pregnancy.