Radiofrequency echographic multispectrometry (REMS) in rare bone conditions

In recent years there has been a growing interest in radiofrequency echographic multispectrometry (REMS), an innovative technology, free of ionized radiation, that is capable of providing important information on bone status. In particular, REMS has been shown to measure bone mineral density (BMD) at axial skeletal bones with a precision, repeatability and accuracy not inferior to those of dual-energy X-ray absorptiometry (DXA). Moreover, REMS may be useful in the assessment of impaired bone quality (e.g., in patients with type 2 diabetes mellitus) and to predict fragility fracture risk. Due to these characteristics, REMS could be usefully used in the diagnosis and follow up of rare bone diseases. In 41 adult subjects (mean age 40.5 ± 18.7 years) with osteogenesis imperfecta (OI), BMD values at all skeletal sites, obtained using both DXA and REMS, were significantly lower than in controls. BMD by REMS values were significantly lower in patients with types III and IV versus type I OI, whereas BMD by DXA did not differ significantly between the two groups. REMS has also demonstrated excellent diagnostic accuracy in some patients suffering from McCune-Albright or Ehlers-Danlos syndromes. Furthermore, with REMS it is to obtain the real BMD value in the presence of artifacts, and, being free of ionizing radiation, it could be particularly advantageous in children and in women of childbearing age or during pregnancy and breastfeeding. In conclusion, on the basis of these preliminary data, REMS can be considered a precise and reliable technique for the evaluation and monitoring of bone status in individuals with rare bone diseases. KEY WORDS: Rare bone diseases, bone mineral density (BMD), dual-energy X-ray absorptiometry (DXA), radiofrequency echographic multispectrometry (REMS), osteogenesis imperfecta.