The determination of muscle volume with a freehand 3D ultrasonography system.

Muscle morphology determines muscle function. An objective method to determine muscle volume in vivo will facilitate understanding of basic muscle function and will also provide a valuable tool for the clinician to assess the effectiveness of treatment. In this method-validation study, it is hypothesised that a freehand 3-D ultrasonography system provides a noninvasive method that allows the determination of muscle volume with high accuracy and precision. To test the hypotheses, repeated measurements were performed (1) on cadaver muscles in situ, (2) isolated muscles and (3) live animals. Volume measurements performed with 3-D ultrasonography were compared with measurements based on computed tomography and the water displacement method. The results of this study showed that 3-D ultrasound provided excellent precision and accuracy in the measurements on the isolated muscles and good precision in vivo. It is concluded that 3-D ultrasonography is an innovative technique that allows objective determination of muscle volume in vivo.