Applying Ultrasound Elastography To Detecting Skeletal Muscle Injury
Skeletal muscle injuries are frequent in sports and exercise, accounting for between 2055% of all sports injuries, with the vast majority of these injuries being muscle strains or contusions. Although muscle injuries are primarily diagnosed through symptomatology and examination of the injury mechanism, medical imaging techniques such as magnetic resonance imaging (MRI) and ultrasound imaging (US) are gaining popularity for assistance with both diagnoses and prognoses. These imaging techniques provide valuable structural and physiological information that is provides more insight into the nature and extent of the damage to guide image treatment. Currently, MRI is the gold standard for use with musculoskeletal applications, but US is becoming more widespread due to its affordability, portability, and real-time imaging capabilities. Ultrasound elastography (USE) is a family of techniques that are used to allow the visual analysis and quantification of the mechanical properties of soft tissue. Injury induced changes in muscle structure affect the mechanical properties of the tissue, and can be detected using USE. Since the echogenicity of a tissue is not directly related to its mechanical properties, ultrasound elastography can extract important information about tissue stiffness and deformability that might not otherwise be attainable. Such mechanical information is especially useful in distinguishing between fibrotic tissue and fatty infiltration. The goal of this thesis is to develop USE as an affordable, fast, and readily available alternative to MRI for early stage diagnosis of acute muscle injury. In pursuit of this goal, we first developed a technique to obtain repeatable and reproducible strain images using USE. We found that a simple averaging procedure performed on 4-8 repeated USE compression cycles significantly improved both the reproducibility and repeatability of the resulting strain images compared to strain images generated using an automated USE system. We then showed that USE combined with principal component analysis can be used to quantify and locate muscle injury in a finite element model, and can feasibly be applied to strain images generated using USE. Finally, we attempted to use the procedures developed in the first two studies to detect and monitor contusion injury in a rat model. However, due to equipment limitations, the results of this study were inconclusive. This thesis is concluded by a summary of the overall findings and discussion of future work.
ultrasound; elastography; skeletal muscle
Hernandez, Christopher J.; Reeves, Anthony P
Ph.D. of Mechanical Engineering
Doctor of Philosophy
dissertation or thesis