Traditionally, ultrasound B-Mode imaging has been designed for allowing a visual evaluation of human organs and their features by clinicians; however, this implies that the huge quantity of information carried by ultrasound signals is processed and significantly reduced for visualization purposes. REMS technology instead analyses the raw, unfiltered ultrasound signals by comparing their spectral representation with the spectral models stored in a proprietary database which has been previously obtained from healthy and osteoporotic patients; these models are specific and vary with sex, age, BMI and skeletal site. The comparison allows the BMD estimation of the patient as well as a both fast and reliable diagnostic classification, compliant to the recommendations and diagnostic criteria defined by the World Health Organization.