Bone Quality Assessment with a Novel Three-Bore Magnet Extremity MRI Scanner

骨质疏松症和相关的代谢性骨病几乎是与晚期骨质疏松症相关的普遍问题 年龄，特别是绝经后妇女，预计到2020年每年将使社会损失超过220亿美元，以及 导致每年65,000人死于骨脆性骨折。最近的研究表明 MRI对于解决与骨骼质量相关的几个因素可能特别有用，而这些因素只能 在患者中进行困难测量。高空间分辨率磁共振成像可以用来准确地描述 小梁微结构，并进行治疗，不伴随DXA的电离辐射剂量 或者CT检查。固态MRI可以唯一无创地测量有机骨基质含量，以及 矿物。质子(1H)固体核磁共振用于骨基质的测量，而磷(31P)固体用于骨基质的测量 MRI具有准确评估3D骨密度的潜力。将这两个度量值组合在 单一的同时测量可以促进对代谢性骨病的更有信息的诊断， 特别是在结合高空间分辨率3D小梁成像的情况下。 核磁共振是一种昂贵的测量方法，不能用于筛查或诊断代谢性骨骼。 疾病。然而，如果核磁共振的成本能够大幅降低，这样的测量可能会成为 在财务上与DXA竞争，同时提供显著增加的诊断信息内容， 同时彻底消除电离辐射照射。 在这个项目中，我们将开发一种mri方法来描述代谢性骨病。 独特的专用、廉价、紧凑、无冷冻剂的四肢MRI扫描仪 之前由美国国立卫生研究院资助的项目。值得注意的是，这款扫描仪的磁铁设计为舒适和 有效的肢体扫描，特别是包含三个孔：一个中央孔，即在 其中插入被扫描的肢体，并且两个外围的“非活动”孔舒适地接受腿部 没有被扫描。这台扫描仪的资本和运营成本，以及诊所的房地产呢 比典型的全身扫描仪要低得多。在撰写本文时，第二代 具有多个开口的紧凑型可倾斜磁体可能会在这个项目开始时到达PI的实验室。 具体目标是：1)进一步发展骨小梁高空间分辨率三维磁共振成像技术 网络结构，以及定量骨矿和基质的固态质子和磷磁共振成像 测量；2)评估固态MRI在模体中对这些测量的定量准确性， 动物组织和活体动物；3)评估高空间分辨率和固体的重复性和准确性 健康志愿者的状态MRI扫描；4)代谢性骨病患者的研究 以及年龄和性别匹配的正常人对基于MRI的骨骼的准确性进行初步评估 并获得统计信息，以允许设计未来的临床试验。

Osteoporosis and related metabolic bone diseases are nearly universal problems associated with advanced age, particularly for postmenopausal women, expecting to cost society over $22 billion annually by 2020, and leading to 65,000 deaths each year stemming from bone fragility fractures. Recent studies have demonstrated that MRI may be of particular utility for addressing several factors related to bone quality that can only be measured with difficulty in patients. High spatial resolution MRI can be used to accurately characterize trabecular microarchitecture, and follow it with treatment, without the attendant ionizing radiation dose of DXA or CT. Solid state MRI can uniquely measure the organic bone matrix content noninvasively as well as the mineral. Proton (1H) solid state MRI has been used to measure bone matrix, while phosphorus (31P) solid state MRI has potential to accurately assess 3D bone mineral density. Combining these two measurements in a single simultaneous measurement could facilitate a more informative diagnostic for metabolic bone disease, especially if coupled with high spatial resolution 3D trabecular imaging. MRI is an expensive measurement, and not justified for screening for or diagnosing metabolic bone disease. However, if the cost of MRI could be drastically reduced, such measurements could become financially competitive with DXA while providing significantly increased diagnostic information content, and at the same time completely eliminating ionizing radiation exposure. In this project, we will develop the methodology of MRI characterization of metabolic bone disease using a unique dedicated inexpensive, compact, cryogen-free extremity MRI scanner designed and constructed in a previous NIH-funded project. Notably, the magnet of this scanner has been designed for comfortable and efficacious extremity scanning, and in particular contains three bores: a central bore that is the “active” bore in which the limb being scanned is inserted, and two peripheral “nonactive” bores that comfortably accept the leg not being scanned. Both the capital and operating costs of this scanner, as well as the clinic “real estate” it occupies, are drastically lower than for the typical whole body scanner. As of this writing, a second generation compact tiltable magnet with multiple openings may arrive in the PI's lab by the beginning of this project. The specific aims are: 1) Further the technical development of high spatial resolution 3D MRI of trabecular network architecture, and solid state proton and phosphorus MRI for quantitative bone mineral and matrix measurement; 2) Assess the quantitative accuracy of solid state MRI for these measurements in phantoms, animal tissues, and live animals; 3) Evaluate the repeatability and accuracy of high spatial resolution and solid state MRI scanning in healthy volunteer subjects; and 4) Carry out studies of metabolic bone disease patients and age- and gender-matched normals to make a preliminary assessment of the accuracy of MRI-based bone characterization, and to acquire statistical information that will permit the design of future clinical trials.