Magnetic resonance biomarkers of muscle degeneration in patients with rotator cuff tears

项目摘要 组织学研究表明，肩袖撕裂后的退变过程不仅仅是 脂肪堆积，包括功能性收缩组织减少和血流灌注改变。组织学 由于对组织进行取样所需的侵入性方法(活检)，临床研究中的措施受到限制。 定量磁共振(MR)成像和光谱分析可以测量退变过程 骨骼肌，跟踪疾病进展和治疗效果。基于磁共振成像的血氧水平- Dependent(MRI-BOLD)和31P-MRS(31P-MRS)是肌肉的可靠估计 微血管功能和能量状态，这是肌肉功能和质量的决定因素。核磁共振的改变- BOLD和31P-MRS与下肢无力和步态表现下降有关，与 衰老，以及与骨骼肌病理性疾病相关的退化。因此，MRI-BOLD 与需要组织采样的肌肉功能和质量测量相比，31P-MRS提供了优势。这些 标记物可以增强对肩袖肌腱退变过程的机械理解 泪水，并可能为治疗效果提供量化措施，这是至关重要的 考虑到最近出现的生物强化处理方法。最终，他们可以积极地 影响每年超过450万寻求治疗肩袖撕裂的美国人的护理。这个项目 将使用磁共振衍生标记物(MRI-BOLD、31P-MRS)来研究微血管功能和能量状态 30例全层冈上肌撕裂患者的冈上肌损伤，最常撕裂的旋转肌 袖带肌腱。30名年龄和性别匹配的无肩痛或肩袖影像证据的个体 泪水将被招募为对照组。本项目有三个具体目标：1)研制一台测功机 在MR扫描过程中实时检测肩外展力；2)测试收缩后MRI-BOLD的假设 31P-MRS评价冈上肌的反应和能量状态在完全性-多发性肌炎患者之间存在差异。 冈上肌腱撕裂厚度与对照组相比；以及3)检验MRI-BOLD的假设 冈上肌的反应和能量状态预测患者的肩部功能和外展力量 在考虑了性别、疼痛和脂肪的预测差异后，出现全层冈上肌腱撕裂 积累。这项研究的完成将通过提供非侵入性的 测量全层冈上肌腱撕裂患者的肌肉血管和能量状态。 这些措施将促进对肩袖肌腱撕裂后退变机制的了解。 未来的临床研究将评估冈上肌退变/再生对患者的影响 症状和有希望的治疗方法的有效性。最终，这项创新的建议将为 基金会，以促进我们处理和治疗肩袖撕裂的方式的范式转变。

PROJECT ABSTRACT Histological studies showed that the degenerative process following rotator cuff tears goes beyond the mere accumulation of fat and includes diminished functional contractile tissue and altered perfusion. Histological measures are limited in clinical studies due to the invasive methods (biopsy) necessary to sample tissue. Quantitative magnetic resonance (MR) imaging and spectroscopy can measure the degenerative process in skeletal muscles, track disease progression and therapeutic efficacy. MR imaging-based Blood Oxygen Level- Dependent (MRI-BOLD) and 31phosphorus MR spectroscopy (31P-MRS) are reliable estimates of muscle microvascular function and energetic status, which are makers of muscle function and quality. Alterations of MRI- BOLD and 31P-MRS are related to lower extremity weakness and decreased gait performance associated with aging, as well as the degeneration associated with pathological disorders of skeletal muscles. Thus, MRI-BOLD and 31P-MRS offer advantages over measures of muscle function and quality that require tissue sampling. These markers may enhance the mechanistic understanding of the degenerative process following rotator cuff tendon tears, and may provide quantitative measures for treatment efficacy, which is of the utmost importance considering the recent advent of biological augmented treatment approaches. Ultimately, they can positively impact the care of over 4.5 million Americans who seek treatment for rotator cuff tears each year. This project will use MR-derived markers (MRI-BOLD, 31P-MRS) to investigate microvascular function and energetic status of the supraspinatus in 30 individuals with full-thickness supraspinatus tears, the most commonly torn rotator cuff tendon. Thirty age and sex-matched individuals without shoulder pain or imaging evidence of rotator cuff tears will be recruited as controls. This project has three specific aims: 1) Develop a dynamometer to measure shoulder abduction force in real-time during MR scans; 2) Test the hypothesis that post-contractile MRI-BOLD response and energetic status evaluated with 31P-MRS of the supraspinatus differ between patients with full- thickness supraspinatus tendon tears versus control individuals; and 3) Test the hypothesis that the MRI-BOLD response and energetic status of the supraspinatus predict shoulder function and abduction strength in patients with full-thickness supraspinatus tendon tears, after accounting for the variance predicted by sex, pain, and fat accumulation. Completing this study will advance the field of quantitative imaging by providing non-invasive measures of muscle vascularity and energetic status in individuals with full-thickness supraspinatus tendon tears. These measures will advance the understanding of the degenerative mechanisms after rotator cuff tendon tears. Future clinical research will evaluate the impact of supraspinatus degeneration/regeneration on patients’ symptoms and the efficacy of promising treatment approaches. Ultimately, this innovative proposal will lay the foundation to promote a paradigm shift in the way we approach and treat rotator cuff tears.