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

描述（由申请人提供）：本研究的长期目标是开发和验证新型成像和生物力学建模技术，以确定导致个体患者关节损伤和疾病的因素。本研究的第一个目的是开发和验证一个系统，以量化关节运动学在体内使用实时磁共振成像（MRI）。实时（MRI）提供了一种独特的成像方式来研究健康和病理关节的运动。第二个目标是开发一个基于图像的建模管道，以估计在生理负荷条件下的体内软骨应力。最后，我们将使用这个模型框架来研究一种常见的肌肉骨骼疾病，髌股（PF）疼痛的病因。 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。一个刚体跟踪技术，然后将被用来提取三维运动的骨骼从实时图像。将通过跟踪MR兼容动态体模的运动来测试该系统的准确度。然后将开发基于图像的有限元（FE）建模管道，以纳入从MRI获得的患者特定软骨材料特性。将进行尸体研究，以将来自MRI的软骨的T1和T2弛豫时间与软骨硬度相关联。FE模型的肌肉力将使用考虑患者特定肌肉激活模式的肌肉骨骼模型进行估计。最后，这些成像和建模工具将用于评估PF疼痛的机械病因。我们将测试一个常见的临床假设，即PF疼痛与软骨应力增加有关。我们将估计在体内软骨应力在一组PF疼痛患者（n=40）和一组无痛对照组（n=20）在静态和动态蹲任务。我们将研究一些可能影响软骨应力的因素，包括：PF关节轨迹不良、接触面积、关节接触力、改变的软骨刚度和软骨厚度。 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，这可能导致长时间的不活动，加速骨关节炎和其他健康问题的发作和进展。本研究开发的新型成像和生物力学建模技术将用于改善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.