Novel Radial MRI Methods for Fast, Motion Compensated DCE-MRI

描述（由申请人提供）：动态对比增强MRI（DCE-MRI）在肿瘤诊断和评估其对治疗的反应中起着关键作用。必须达到高的时间分辨率，以准确地确定肿瘤增强动力学。此外，需要足够的空间分辨率来识别和跟踪小病灶以及评估瘤内异质性。此外，有一个潜在的需要，大容量或全器官成像的评价多个转移性病变。不幸的是，使用当前技术，在高时间分辨率、高空间分辨率和体积覆盖之间存在折衷。因此，难以在单次扫描中采集能够同时满足这些不同标准的动态MR成像系列。此外，当在胸部或腹部转移性疾病患者中应用DCE-MRI时，呼吸运动进一步使问题复杂化。因此，利用现有技术，精确地评估肺或肝肿瘤的灌注是极其困难的。在这里，我们建议开发，实施和验证新的策略，以改善量化的肿瘤对比动力学在3D DCE-MRI，在一个单一的动态系列，高的时间和空间分辨率，结合有效的运动补偿的目标。所提出的工作是基于放射状数据采集和重建策略的基础上的黄金角视图顺序计划，这允许（1）高度灵活的重建方案，允许增强的时间分辨率;和（2）有效的自门控策略的呼吸运动补偿。我们的总体假设是，所提出的径向DCE-MRI方法将显着提高肿瘤灌注测量的可靠性，在呼吸运动可能严重妨碍准确分析的区域。该提案的具体目标如下：具体目标1：探索用于径向DCE-MRI中呼吸运动补偿的新型自门控策略。我们将研究改进的方法，以提高呼吸自门控径向DCE-MRI的时间分辨率，并研究补偿残余运动的技术。具体目标2：开发优化的图像重建策略，用于准确的肿瘤灌注评估。我们将开发优化灌注测量精度的图像重建策略。我们还将研究更完全自动化图像重建过程的方法。具体目标3：在良性肝脏病变受试者中评价用于DCE-MRI评价的拟议径向与传统直线采集方案。将进行一项随机化研究，以检验以下假设：当与用于DCE-MRI图像采集的传统成像方法相比时，目标1和2中概述的拟定方法将产生具有上级图像质量的数据集，并将导致肿瘤灌注的可重现性更高的DCE-MRI定量。公共卫生相关性：动态对比增强MRI在肿瘤诊断和评估其对新疗法的反应方面起着关键作用。然而，由于高空间分辨率、高时间分辨率和体积覆盖之间的权衡，现有技术难以准确地评估病变，特别是位于胸部或腹部的病变，其中呼吸运动使测量进一步复杂化。所提出的方法提供了一种手段，通过允许高空间和时间分辨率成像与大体积覆盖，结合呼吸运动补偿的有效策略，准确评估肿瘤灌注。

DESCRIPTION (provided by applicant): Dynamic contrast-enhanced MRI (DCE-MRI) plays a critical role in the diagnosis of tumors and in assessing their response to therapy. High temporal resolution must be achieved to accurately determine tumor enhancement kinetics. In addition, sufficient spatial resolution is needed for the identification and tracking of small lesions and for assessing intratumoral heterogeneity. Furthermore, there is a potential need for large volume or whole-organ imaging for the evaluation of multiple metastatic lesions. Unfortunately, using current techniques, there are tradeoffs between high temporal resolution, high spatial resolution, and volumetric coverage. It is therefore difficult to acquire a dynamic MR imaging series able to simultaneously meet these diverging criteria in a single scan. Moreover, respiratory motion further complicates the problems when applying DCE-MRI in patients with metastatic disease in the chest or the abdomen. With existing technology, it is therefore extremely difficult to accurately assess perfusion of lung or liver tumors. Here we propose to develop, implement, and validate novel strategies for improved quantification of tumor contrast kinetics in 3D DCE-MRI, with the goal of achieving in a single dynamic series, high temporal and spatial resolutions, in conjunction with effective motion compensation. The proposed work is based on radial data acquisition and reconstruction strategies based on the golden-angle view order scheme, which permit (1) highly flexible reconstruction schemes allowing for enhanced temporal resolution; and (2) effective self-gating strategies for respiratory motion compensation. Our overall hypothesis is that the proposed radial DCE-MRI methodology will significantly improve the reliability of tumor perfusion measurements in regions where respiratory motion can seriously hamper accurate analysis. The specific aims of this proposal are as follows: Specific Aim 1: Explore novel self-gating strategies for compensation of respiratory motion in radial DCE- MRI. We will investigate improved methods to enhance the temporal resolution of respiratory self-gated radial DCE-MRI and investigate techniques to compensate for residual motion. Specific Aim 2: Develop optimized image reconstruction strategies for accurate tumor perfusion assessment. We will develop strategies for image reconstruction that optimizes perfusion measurement accuracy. We will also examine methods to more fully automate the image reconstruction process. Specific Aim 3: Evaluate the proposed radial versus conventional rectilinear acquisition schemes for DCE-MRI evaluation in subjects with benign liver lesions. A randomized study will be carried out to test the hypothesis that the proposed methodologies outlined in Aims 1 and 2-when compared against conventional imaging methods for DCE-MRI image acquisition-will yield data sets with superior image quality, and will result in more reproducible DCE-MRI quantification of tumor perfusion. PUBLIC HEALTH RELEVANCE: Dynamic contrast-enhanced MRI plays a critical role in the diagnosis of tumors and in assessing their response to new therapies. However, due to the tradeoffs among high spatial resolution, high temporal resolution, and volumetric coverage, it is difficult with existing techniques to assess lesions accurately, particularly those that are located in the chest or abdomen where respiratory motion further complicates measurement. The proposed approach provides a means for accurate assessment of tumor perfusion by permitting high spatial and temporal resolution imaging with large volume coverage, in conjunction with an effective strategy for respiratory motion compensation.