NON CONTRAST ENHANCED CEREBRAL ANGIOGRAPHY AT 7T BASED ON MPRAGE IMAGES

基于 MPRAGE 图像的 7T 非对比增强脑血管造影

• 批准号: 8362878
• 负责人: Pierre-Francois VAN DE MOORTELE
• 金额: $ 3.03万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8362878
• 关键词: Angiography; Blood; Brain; Cerebral Angiography; Cerebrospinal Fluid; Cerebrum; Characteristics; Clinical; Deposition; Funding; Grant; Gray unit of radiation dose; Image; Imagery; Magnetic Resonance Imaging; Morphologic artifacts; Motion; NMR Spectroscopy; National Center for Research Resources; Physiologic pulse; Preparation; Principal Investigator; Process; RF coil; Research; Research Infrastructure; Resources; Signal Transduction; Source; Time; Tissues; United States National Institutes of Health; Variant; Weight; base; brain tissue; cerebral artery; cost; novel strategies; white matter

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In this project we propose a new approach to obtain non contrast enhanced whole brain angiography at 7T. The principle consists in acquiring 3D MPRAGE T1 weighted images and normalizing the latter with a 3D gradient echo image obtained with same parameters but without inversion preparation pulse. Rationale. We have previously shown with T1 weighted anatomical images that these ratio images preserve excellent gray/white matter T1 contrast while removing strong artifacts that hamper clinical usage of 7Tesla images, especially large signal intensity variations due to RF coil sensitivity profile. In these ratio images signal intensity is typically less than unity for brain tissue and for cerebrospinal fluid. Arterial blood signal, however, is greater than unity in these images. This characteristics can significantly ease the process of eliminating background tissue signals to generate maximum intensity projections in order to visualize cerebral arteries. Compared with standard time of flight vessel imaging, this approach also requires significantly lower levels of RF power, thus lower SAR deposition in tissues. Objectives. 1) First, we will optimize MPRAGE based angiography and systematically compare the latter with standard time of flight angiography. Results will be compared in term of image quality, coverage of the cerebral arterial vasculature, smallest visualized vessel size, sensitivity to motion artifacts, SAR, and acquisition time. 2) Second, acquisition parameters will be altered in order to determine if an acceptable trade off can be found between brain tissue T1 contrast and cerebral vessel visualization in order to generate both images in a single acquisition.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 在这个项目中，我们提出了一种在 7T 下获得非对比增强全脑血管造影的新方法。其原理在于采集 3D MPRAGE T1 加权图像，并使用使用相同参数但没有反转准备脉冲获得的 3D 梯度回波图像对后者进行归一化。理由。我们之前通过 T1 加权解剖图像表明，这些比率图像保留了出色的灰/白质 T1 对比度，同时消除了阻碍 7Tesla 图像临床使用的强烈伪影，特别是由于射频线圈灵敏度分布而导致的大信号强度变化。在这些比率图像中，脑组织和脑脊液的信号强度通常小于统一值。然而，这些图像中的动脉血信号大于统一信号。这一特性可以显着简化消除背景组织信号的过程，以生成最大强度的投影，从而使脑动脉可视化。与标准飞行时间血管成像相比，这种方法还需要显着降低的射频功率，从而降低组织中的 SAR 沉积。目标。 1）首先，我们将优化基于MPRAGE的血管造影，并将后者与标准飞行时间血管造影进行系统比较。将在图像质量、脑动脉脉管系统覆盖范围、最小可视化血管尺寸、对运动伪影的敏感性、SAR 和采集时间方面对结果进行比较。 2) 其次，将改变采集参数，以确定是否可以在脑组织 T1 对比度和脑血管可视化之间找到可接受的权衡，以便在单次采集中生成两个图像。