Demonstration of extended field-of-view ultrasound's potential to increase the pool of muscles for which in vivo fascicle length is measurable

J Biomech. 2017 Oct 3:63:179-185. doi: 10.1016/j.jbiomech.2017.08.012. Epub 2017 Aug 23.

Abstract

Static, B-mode ultrasound is the most common method of measuring fascicle length in vivo. However, most forearm muscles have fascicles that are longer than the field-of-view of traditional ultrasound (T-US). As such, little work has been done to quantify in vivo forearm muscle architecture. The extended field-of-view ultrasound (EFOV-US) method, which fits together a sequence of B-mode images taken from a continuous ultrasound scan, facilitates direct measurements of longer, curved fascicles. Here, we test the validity and reliability of the EFOV-US method for obtaining fascicle lengths in the extensor carpi ulnaris (ECU). Fascicle lengths from images of the ECU captured in vivo with EFOV-US were compared to lengths from a well-established method, T-US. Images were collected in a joint posture that shortens the ECU such that entire fascicle lengths were captured within a single T-US image. Resulting measurements were not significantly different (p=0.18); a Bland-Altman test demonstrated their agreement. A novice sonographer implemented EFOV-US in a phantom and in vivo on the ECU. The novice sonographer's measurements from the ultrasound phantom indicate that the combined imaging and analysis method is valid (average error=2.2±1.3mm) and the in vivo fascicle length measurements demonstrate excellent reliability (ICC=0.97). To our knowledge, this is the first study to quantify in vivo fascicle lengths of the ECU using any method. The ability to define a muscle's architecture in vivo using EFOV-US could lead to improvements in diagnosis, model development, surgery guidance, and rehabilitation techniques.

Keywords: Fascicle length; Forearm; Muscle architecture; Skeletal muscle; Ultrasonography.

MeSH terms

  • Adult
  • Animals
  • Female
  • Forearm / diagnostic imaging*
  • Humans
  • Male
  • Muscle, Skeletal / diagnostic imaging*
  • Reproducibility of Results
  • Ultrasonography / methods
  • Young Adult