Magnetic Resonance Elastography as a Personalized Assessment of Intervertebral Disc Mechanics

项目总结/摘要 下背痛（LBP）是世界范围内残疾的主要原因，腰椎成像已变得无处不在， 这是标准的治疗过程然而，典型的临床成像仅提供脊柱的定性评估， 解剖学和“改善慢性腰痛患者预后分层的新研究”， 最近由NIH疼痛联盟慢性LBP研究标准工作组呼吁。 椎间盘退变（IVD）是LBP的主要或次要原因，其特征在于进行性 组织结构和组成的破坏导致机械行为和内部结构的改变， 破坏可以为神经长入提供一种手段，这是椎间盘源性疼痛的前兆。磁共振 弹性成像（MRE）是一种非侵入性成像技术，可在应变波移动时跟踪其传播 通过软组织，并允许在体内测量组织材料特性。支持数据 证明MRE衍生的剪切刚度可以作为对这种疾病过程敏感的生物标志物， 与非操作对照相比，可以检测操作IVD内的内部中断。然而，地雷危险教育得到改善， 减少扫描时间的扫描序列，MRE衍生粘弹性的机械验证，以及 在临床使用之前，需要确定MRE检测到的内部破坏的限度。 这项研究的长期目标是提供一种安全和非侵入性的方法来量化机械 脊柱内肌肉骨骼软组织的功能，以允许损伤和疾病的早期诊断，改善 患者分层和促进LBP的恢复性干预的体内评价。目标1开发定制 自旋回波回波平面成像MRE序列，以减少扫描时间，同时增加SNR。目的 2验证了健康和退化IVD组织的MRE衍生粘弹性材料特性， 材料测试，并确定类型，方向和最小缺陷尺寸，MRE可以检测到， 尸体组织目标3确定MRE导出的材料性能和内部缺陷测量值是否 与组织成分中的空间变化的MR测量一起可以区分疼痛和非疼痛。 无症状受试者和椎间盘相关慢性LBP患者的疼痛IVD。这项工作将 在缩短时间内改进数据收集，这适用于所有MRE应用， 粘弹性力学性能和内部损伤的评估。IVD的非侵入性体内评估 机械功能可以使LBP患者的预后分层，并作为一种新的“患者特异性” 临床工具，用于识别损伤并量化疾病和治疗的功能后果。

Project Summary / Abstract Low back pain (LBP) is the leading cause of disability worldwide and lumbar imaging has become ubiquitous in its standard course of care. However, typical clinical imaging offers only a qualitative assessment of spine anatomy and “new research to improve prognostic stratification of patients with chronic low back pain” was recently called for by the NIH Pain Consortium Task Force on Research Standards for Chronic LBP. Intervertebral disc (IVD) degeneration, a primary or secondary cause of LBP, is characterized by the progressive breakdown of the tissue's structure and composition resulting in altered mechanical behaviors and internal disruptions that can provide a means for nerve ingrowth, a precursor for discogenic pain. Magnetic resonance elastography (MRE) is a non-invasive imaging technique that tracks propagating strain waves as they move through soft tissues and allows the measurement of tissue material properties in-vivo. Supporting data demonstrates that MRE-derived shear stiffness can serve as a biomarker sensitive to this disease process and can detect internal disruptions within operated IVDs compared to non-operated controls. Yet, improved MRE scan sequences to reduce scan time, mechanical validation of MRE-derived viscoelastic properties, and determination of the limits of MRE-detected internal disruptions are required prior to clinical utilization. The long-term goal of this research is to provide a safe and non-invasive method to quantify the mechanical function of musculoskeletal soft-tissues within the spine to allow early diagnosis of injury and disease, improve patient stratification and facilitate in-vivo evaluation of restorative interventions for LBP. Aim 1 develops a custom spin-echo echo-planar imaging MRE sequence to reduce scan times while simultaneously increasing SNR. Aim 2 validates the MRE-derived viscoelastic material properties of healthy and degenerated IVD tissue against material testing and also determines the type, orientation and minimum defect size that MRE can detect in cadaveric tissue. Aim 3 determines if MRE-derived measurements of material properties and internal defects together with MR measurements of spatial variations in tissue composition can differentiate a painful and non- painful IVD from asymptomatic subjects and disc-related chronic LBP patients, respectively. This work will improve data collection in a reduced time, which is applicable to all MRE applications, and allow in-vivo assessment of viscoelastic mechanical properties and internal damage. Non-invasive in-vivo assessment of IVD mechanical function may allow the prognostic stratification of LBP patients and serve as a novel “patient specific” clinical tool to identify damage and quantify the functional consequences of disease and treatment.