Assessing Bone Mineral Density Using Radiofrequency Echographic Multi-Spectrometry

Abstract

Source:
Piera Lalli¹, Elisabetta Quilico¹, Chiara Busso¹, Marta Andrighetti¹, Cristina Graziano¹, Paola Pisani², Marco A. Minetto<sup>1

1</sup>Division of Physical Medicine and Rehabilitation, Department of Surgical Sciences, University of Turin.

²Institute of Clinical Physiology, National Research Council.

This video demonstrates the radiofrequency echographic multi-spectrometry (REMS) technique for assessing bone mineral density (BMD). The patient is positioned supine, and ultrasound gel is applied to the femoral neck, a fracture-prone site in the femur. The probe then emits ultrasound waves, which reflect off the bone tissue at a speed influenced by BMD. The probe captures these reflected waves, enabling the quantification of BMD.

Protocol

1. System preparation

NOTE: The system (EchoStation in the Table of Materials) is composed of a touch screen monitor, a main unit, and a 3.5 MHz ultrasound convex probe.

1. Switch on the monitor by pressing the power button on the top left edge of the unit. The operation will take a few seconds.
2. Tap the icon of the software at the top right of the screen
3. Insert the user identifier and password, then tap the Start button  
4. Switch on the main unit by pressing the power button on the device

2. Subject preparation

1. Ask the subject to be dressed in undergarments.
2. Measure the weight and height of the subject using a standard scale with a stadiometer.
3. Ask the subject to lay supine on a medical bed, with the lower limbs positioned in a neutral position.

3. Subject registration

1. Fill in the registration form, including first name, surname, date of birth (the software automatically calculates the age), gender, menopause age (if female), ethnicity (select among Asian, Caucasian, Hispanic, Black), weight and height (the software automatically calculates the body mass index)
2. Select the scan site of interest (spine or femur).
   1. Select Femur for the femoral scan
   2. A drop-down menu automatically opens: select Right or Left
3. Tap the Save button: after a few seconds, a live scan window will be shown.

4. Scan acquisition

1. Place the probe on the skin above the femoral neck, parallel to the head-neck axis (Figure 1A), to visualize the proximal femur profile (Figure 1B)
2. Using the buttons on the left side of the touch screen, adjust the scan depth (select one depth from 60 to 150 mm as shown in the left column of Table 1) and the depth of the focus identified by the red line in the ultrasound image (select one of the depths shown in the right column of Table 1) in order to have the target bone interface in the ultrasound beam focal zone at about halfway through the depth of the B-mode image (Figure 1B).
3. Tap the Start button or press the space bar on the keyboard to initialize the scan and ask the subject to remain as still as possible during the 40 s acquisition.

5. Data analysis and report

1. After the ultrasound image capture, wait for the software to automatically perform the analysis, showing the following message: Analysis in progress - The processing could take a few minutes. Press the stop button to cancel the processing.
2. Tap the Stop button to interrupt the process, or wait till the end of the analysis to get the report.
3. Tap the X button at the top right of the report file to close it (the report will be automatically archived).

Inform the subject that the scan is complete.