QUANTITATIVE MAGNETIC RESONANCE IMAGING OF PERFUSION

描述：（改编自申请人的摘要）：本发明的目的是 工作是开发定量非侵入性成像技术， 使用磁共振成像的组织灌注。 这样做的动机 项目太类应用：灌注成像的临床应用 用于急性中风的非侵入性诊断和治疗评估;以及 大脑功能灌注绘图，用于临床应用 例如神经外科手术前的计划，或用于脑功能的基础研究。 所使用的灌注成像技术是基于磁标记的。 用射频脉冲检测动脉水 当前基于MRI的技术 可以生成灌注图，但不准确，不及时， 适合多切片或3D采集。 几个影响包括 现有技术的准确性，包括：标签的误解 作为切片的灌注而穿过切片的血液;空间上的 在动脉标签的应用和动脉标签的应用之间的变化的传输延迟， 标记血液到达成像切片;交换标记水 在血管和血管外隔室之间， 弛豫参数;和磁化转移（MT）效应。 第一 该项目的目标是设计成像技术，测量这些 效果，使用梯度和射频脉冲的组合， 选择性地破坏来自特定质子群的信号， 控制动脉标签的特性。 重大进展 在个别处理其中一些影响时， 单一技术可以声称是真正的定量技术。 几乎可以肯定 需要一系列成像技术来严格控制， 所有的混杂效应，以及由此产生的灌注检查， 会耗费大量时间 第二个总体目标是 项目是探索技术，尽量减少，而不是测量，这些 为了创建时间有效的灌注， 测量，并将其与所描述的更严格的技术进行比较 以量化引入灌注测量的可能误差。 第三个目标是探索将这些技术推广到 多层或3D。 这种扩展并不像大多数 成像技术，由于标记方案和MT的性质， 影响，并将需要特别注意衡量过境延误 以及MT效应的频率依赖性。 最后，在应用中， 感兴趣量是灌注的动态变化，例如功能性的 急性中风的成像或治疗，血氧变化， 通过时间可能混淆灌注测量， 来自灌注测量的这些效果是第四个目标。

DESCRIPTION: (Adapted from Applicant's Abstract): The objective of this work is to develop techniques for quantitative non-invasive imaging of tissue perfusion using magnetic resonance imaging. The motivation for this project is too classes of applications: clinical use of perfusion imaging for non-invasive diagnosis and evaluation of therapy in acute stroke; and functional perfusion mapping of the brain, either for clinical applications such as pre-neurosurgical planning, or for basic studies of brain function. The perfusion imaging techniques used are based on magnetic labeling of arterial water using radiofrequency pulses. Current MRI based techniques can generate perfusion maps, but are inaccurate, not time efficient, and not amenable to multislice or 3D acquisition. Several effects comprise the accuracy of existing techniques including: misinterpretation of labeled blood that is passing through a slice as perfusion of the slice; a spatially varying transit delay between the application of the arterial tag and the arrival of tagged blood into the imaging slice; exchange of tagged water between vascular and extravascular compartments which have different relaxation parameters; and magnetization transfer (MT) effects. The first goal of this project is to devise imaging techniques that measure these effects, using combinations of gradient and radiofrequency pulses to selectively destroy signal from specific populations of protons, and controlling the characteristics of the arterial tag. Significant progress has been made in addressing some of these effects individually, but no single technique can claim to be truly quantitative. It is almost certain that a series of imaging techniques will be required to strictly control for all of the confounding effects, and that the resulting perfusion examination will be prohibitively time consuming. The second general goal of this project is to explore techniques that minimize, rather than measure, these confounding effects in the interest of creating a time efficient perfusion measurement, and compare these to the more rigorous techniques described above to quantify possible errors introduced into the perfusion measurement. The third goal is to explore methods for extension of these techniques to multislice or 3D. This extension is not straightforward as it is in most imaging techniques, because of the nature of the tagging schemes and MT effects, and will require particular attention to measured transit delays and the frequency dependence of MT effects. Finally, in applications where the quantity of interest is dynamic changes in perfusion, such as functional imaging or treatment of acute stroke, changes in blood oxygenation and transit times can confound the perfusion measurement, and separation of these effects from the perfusion measurement is a fourth goal.