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首页> 外文学位 >High resolution high field quantitative parallel magnetic resonance imaging for osteoporosis and other clinical applications.
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High resolution high field quantitative parallel magnetic resonance imaging for osteoporosis and other clinical applications.

机译：用于骨质疏松症和其他临床应用的高分辨率高场定量平行磁共振成像。

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摘要

This thesis developed high signal-to-noise ratio (SNR) yielding magnetic resonance imaging (MRI) methods that require relatively short measurement times. The methods were primarily aimed at addressing existing technical limitations of low SNR and long scan times (∼ 20 minutes) in the field of in vivo high resolution (HR) imaging of trabecular bone micro-architecture. HR-MRI of trabecular bone provides a non-invasive way of monitoring trabecular bone structural integrity for assessment of the disease condition, osteoporosis. Osteoporosis is a debilitating skeletal disorder affecting 1 in 3 women and 1 in 12 men over the age of 50 worldwide and is characterized by loss of bone mass and structure leading to atraumatic fractures at the vertebrae, hip, wrists and other sites. SNR limitations in trabecular bone MRI were overcome by incorporating a high magnetization yielding pulse sequence and translating the imaging protocol to the higher field strength of 3 Tesla (T) from the clinical standard of 1.5 T. A simulation model was developed to estimate SNR in bone tissue. The feasibility of imaging trabecular bone structure in vivo at the proximal femur (hip), until then an SNR impeded application, was demonstrated. Next, an autocalibrating parallel imaging (PI) method was implemented to accelerate data acquisition. Using an eight channel coil array, scan time was reduced 2-4 fold without any significant impact on image resolution or edge sharpness; although bone structural measures derived from the accelerated images showed overestimation. Consequently, parallel reconstruction and image processing algorithms were developed to address the causes of overestimation. With the availability of whole body 7 T magnets and the motivation for further improvement in SNR, the PI methods were adapted to the even higher field strength and its performance was found to improve relative to 3 T. To summarize, this thesis developed SNR efficient MR methods that facilitate quantitative HR-MRI of trabecular bone within 2-10 minutes, thus increasing the clinical feasibility of this application. Additionally, the PI methods were applied to diverse applications such as cartilage imaging for osteoarthritis; and susceptibility weighted imaging of brain vasculature and 3D spectroscopic imaging of brain metabolites in brain tumor patients.
机译：本文开发了高信噪比（SNR）的磁共振成像（MRI）方法，需要相对较短的测量时间。这些方法的主要目的是解决小梁骨微结构的体内高分辨率（HR）成像领域中低SNR和长扫描时间（约20分钟）的现有技术局限性。小梁骨的HR-MRI提供了一种非侵入性的方法来监视小梁骨的结构完整性，以评估疾病状况，骨质疏松症。骨质疏松症是一种使人衰弱的骨骼疾病，在全球范围内影响着50岁以上的女性，每3名女性中就有1名，而每12名男性中就有1名男性。骨质疏松的特征是骨骼质量和结构丧失，导致椎骨，髋部，腕部和其他部位发生无创伤性骨折。通过合并高磁化产生脉冲序列并将成像协议从1.5 T的临床标准转换为3 Tesla（T）的更高场强，克服了小梁骨MRI中的SNR局限性。建立了一个仿真模型来估算骨的SNR组织。证实了在股骨近端（髋关节）体内对小梁骨结构进行成像的可行性，直到SNR受阻的应用。接下来，实现了自动校准并行成像（PI）方法以加速数据采集。使用八通道线圈阵列，扫描时间减少了2-4倍，而对图像分辨率或边缘清晰度没有任何重大影响。尽管从加速图像得出的骨骼结构指标显示过高。因此，开发了并行重建和图像处理算法来解决高估的原因。随着全身7 T磁体的可用性以及进一步提高SNR的动机，PI方法适应了更高的场强，并且其性能相对于3 T有所提高。综上所述，本文开发了SNR有效的MR有助于在2-10分钟内对小梁骨进行定量HR-MRI的方法，从而增加了此应用程序的临床可行性。此外，PI方法已应用于多种应用，例如骨关节炎的软骨成像；脑肿瘤患者脑血管的敏感性和敏感性加权成像以及脑代谢物的3D光谱成像。

著录项

  • 作者

    Banerjee, Suchandrima.;

  • 作者单位

    University of California, San Francisco.;

  • 授予单位 University of California, San Francisco.;
  • 学科 Engineering Biomedical.;Health Sciences Radiology.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 159 p.
  • 总页数 159
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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