Real-Time MRI and 3D Modeling: Development and Application to Patellofemoral Pain

描述(申请人提供)：这项研究的长期目标是开发和验证新的成像和生物力学建模技术，以确定导致个别患者关节损伤和疾病的因素。这项研究的第一个目的是开发和验证一种使用实时磁共振成像(MRI)在活体内量化关节运动学的系统。实时(MRI)为研究健康和病理关节的运动提供了一种独特的成像方式。第二个目标是开发一种基于图像的建模管道，以估计生理载荷条件下的活体软骨应力。最后，我们将使用这个建模框架来研究一种常见的肌肉骨骼疾病--膝骨股(PF)痛的病因。 为了实现这些目标，我们将首先提高肌肉骨骼成像的实时MRI的空间和时间分辨率。然后，将使用刚体跟踪技术从实时图像中提取骨骼的三维运动。该系统的准确性将通过跟踪与MR兼容的动态体模的运动来测试。然后将开发基于图像的有限元(FE)建模管道，以结合从MRI获得的患者特定的软骨材料属性。将进行一项身体研究，以研究MRI显示的软骨T1和T2松弛时间与软骨硬度之间的关系。FE模型的肌力将使用肌肉骨骼模型来估计，该模型考虑了患者特定的肌肉激活模式。最后，这些成像和建模工具将被用来评估PF疼痛的机械病因。我们将验证一个常见的临床假设，即PF疼痛与软骨应力增加有关。我们将评估一组PF疼痛患者(n=40)和一组无痛对照组(n=20)在静态和动态下蹲任务中的体内软骨应力。我们将研究一些可能影响软骨应力的因素，包括：PF关节错位、接触面积、关节接触力、改变的软骨硬度和软骨厚度。 肌肉骨骼损伤和疾病是严重的公共卫生问题。膝关节特别容易受伤，这可能会导致长时间的不活动，加速骨性关节炎的发病和进展，以及其他健康问题。这项研究中开发的新的成像和生物力学建模技术将用于改进一系列肌肉骨骼疾病的诊断和治疗。

DESCRIPTION (provided by applicant): The long-term goal of this research is to develop and validate novel imaging and biomechanical modeling techniques to identify factors that contribute to joint injury and disease in individual patients. The first aim of this research is to develop and validate a system to quantify joint kinematics in vivo using real-time magnetic resonance imaging (MRI). Real-time (MRI) provides a unique imaging modality to investigate the motion of healthy and pathological joints. The second aim is to develop an image-based modeling pipeline to estimate cartilage stress in vivo under physiological loading conditions. Finally, we will use this modeling framework to investigate the etiology of a common musculoskeletal disorder, patellofemoral (PF) pain. To achieve these aims, we will first improve the spatial and temporal resolution of the real-time MRI for musculoskeletal imaging. A rigid-body tracking technique will then be used to extract three-dimensional motion of bones from the real-time images. The accuracy of this system will be tested by tracking the motion of an MR-compatible dynamic phantom. An image-based finite element (FE) modeling pipeline will then be developed to incorporate patient-specific cartilage material properties obtained from MRI. A cadaver study will be carried out to correlate T1 and T2 relaxation times of cartilage from MRI with cartilage stiffness. Muscle forces for the FE model will be estimated using a musculoskeletal model that takes into account patient-specific muscle activation patterns. Finally, these imaging and modeling tools will be used to evaluate the mechanical etiology of PF pain. We will test a common clinical hypothesis, that PF pain is related to increased cartilage stress. We will estimate in vivo cartilage stress in a group of PF pain patients (n=40) and a group of pain-free controls (n=20) during static and dynamic squatting tasks. We will investigate a number of factors that may influence the cartilage stress, including: PF joint maltracking, contact area, joint contact forces, altered cartilage stiffness, and cartilage thickness. Musculoskeletal injuries and diseases are serious public health issues. The knee joint is particularly susceptible to injuries, which can lead to prolonged periods of inactivity, accelerated onset and progression of osteoarthritis and other health problems. The novel imaging and biomechanical modeling techniques developed in this research will be used to improve the diagnosis and treatment of a range of musculoskeletal disorders.