3D Freehand Ultrasound for in vivo Determination of Human Skeletal Muscle Volume

Skeletal muscle volume is an important indicator of muscle function. Three-dimensional (3D) freehand ultrasound provides a noninvasive method for determining muscle volume and is acquired using a standard clinical ultrasound machine and an external tracking system to monitor transducer position. Eleven healthy volunteers were scanned with a 3D freehand system that uses an optical tracking device. Interest was concentrated on one of the muscles of the quadriceps group, rectus femoris and volume measurements performed on 30 mm cross-sections were compared with measurements derived from magnetic resonance imaging. Measured muscle volumes ranged from 5 cm3 to 28 cm3. The mean difference between measurements from 3D freehand ultrasound and magnetic resonance was 0.53 cm3 with 95% limits of agreement of ±2.14 cm3. Muscle volume measurements obtained using 3D ultrasound were within ±16% of the corresponding value from magnetic resonance imaging. We have shown for the first time that 3D freehand ultrasound can be used to determine human skeletal muscle volume accurately in vivo. (E-mail: T.J.MacGillivray@ed.ac.uk)