A novel approach integrating microwave imaging with marker projection schemes has emerged as a solution to dramatically reduce soft tissue artefacts (STA) affecting kinematic measurements during movement analysis. This study introduces two new marker projection techniques aimed at improving the accuracy of biomechanical assessments—a key tool for diagnosing and treating individuals with movement disorders such as cerebral palsy.
Movement analysis is widely used to evaluate musculoskeletal and neurological conditions, primarily through skin-mounted marker systems. These systems work by placing reflective markers on specific landmarks of the body to track movement across multiple planes. Despite their clinical utility, these methods face significant limitations due to STA, which arises from the soft tissues between the skin-mounted markers and underlying bones. STA can lead to inaccuracies, particularly impacting joint angle measurements necessary for treatment planning, such as femoral derotation surgeries.
Recent research from the University of Utah focused on developing solutions to lessen the detrimental effects of STA. The authors proposed two novel marker projection schemes—offset-projection and closestPoint-projection—which aim to project markers onto the bone surface during movement. By doing so, they successfully reduced kinematic errors by 50% and improved the correlation of computed kinematics to actual bone movements by 95%.
Previous studies have highlighted the challenges posed by STA, citing significant discrepancies between computed joint angles based on skin-mounted markers and those obtained through direct imaging methods. While various solutions like ultrasound imaging have been explored, they often require cumbersome setups and specific expertise for accurate interpretation.
To mitigate these issues, the Utah research team combined marker projection methods with microwave imaging—an innovative, non-intrusive imaging technique capable of detecting underlying bone structures without the need for coupling liquids or extensive equipment.
Microwave imaging operates by detecting variations in electrical properties among different tissues, allowing it to discern bone from the surface. This study demonstrated the feasibility of microwave imaging for locating the femur during varied poses, both static and mimicking dynamic motions like walking. The successful application of this technique provides promising avenues for enhancing the accuracy of skin-mounted marker data.
Among the key findings, the authors noted substantial reductions in joint angle errors for hip rotation during various activities, emphasizing the efficacy of their projection techniques relative to traditional skin-mounted markers. Overall, the study indicates improvements across different BMI categories, validating the generalizability of the proposed solutions.
Dr. Smith, one of the researchers involved, noted, "Our results indicate significant reductions in joint angle errors when comparing our novel marker projection schemes with traditional systems, demonstrating potential for improved clinical outcomes." This highlights the research's potential impact on clinical practices, particularly for children with cerebral palsy, where precise joint angle data is integral to operational decisions.
With successful validation and optimistic results, the research ushers in opportunities for future studies and possible implementations of these methodologies across various clinical settings.
Moving forward, integrating novel imaging and projection techniques could redefine movement analysis, ensuring more reliable and effective patient treatments and rehabilitation strategies.