Long Field Of View MRA Using Continuous Table Motion

描述(由申请人提供)：该项目的长期目标仍然是开发方法，允许在患者床面连续运动期间采集磁共振数据，用于外围血管的对比增强磁共振血管成像研究。这将允许对从腹部和骨盆到足部的血管系统进行高质量的诊断成像，从而能够诊断和表征周围血管疾病。在连续工作台运动期间的成像允许在使用扫描时间和对比剂剂量方面的高效率。由于给定的轴向水平在移动视场内仅在有限的时间内成像，通常为20秒或更短，因此在给定的采集时间内允许提高空间分辨率是至关重要的。为此，01-04年演示的一维加速技术将扩展到两个横向维。这项研究的另一个主要目的是实时成像对比剂剂量传递，自动跟踪其位置，并使用该信息自动调整工作台速度。资助申请包括以下具体目标：1.使用2D加速技术实现固定视场的高分辨率CE-MRA。为了准备在连续工作台移动期间进行成像，首先将开发在目标16秒内无工作台移动的情况下执行高度加速采集的技术。椭圆中心视图顺序将与2D零差、2D SENSE和1 mm各向同性分辨率的时间分辨视图共享采集相结合。2.在连续工作台运动过程中应用的并行捕获技术。AIM#1的加速捕获方法将适用于连续移动台面成像。将开发考虑梯度翘曲、2D感觉零差和可变视场采集的重建算法。将开发的线圈允许在扩展的视场上进行高效的15倍加速2D并行采集。3.连续移床外周MRA的患者特异性采集。当造影剂沿外周血管系统移动时，将开发检测造影剂前沿的方法，然后使用该信息来实时改变患者床位的运动。这将首先在模体中进行测试，然后使用测试丸进行测试。最后一种技术是通过自动跟踪全对比剂团形成扩展视野、高空间分辨率的动脉相外周血管造影，而不需要测试团。公共卫生相关性：外周血管疾病是美国人口中的一个主要问题，重要的是以一种容易、准确、可靠、安全的方式对这种疾病进行成像和诊断，这种方式不仅考虑到患者之间在解剖和血流方面的差异，而且还适应了从腹部到脚的长视野。这个项目与这个问题相关，因为目标是开发一种方法，通过使用移动的病人床来实现扩展血管的高空间分辨率磁共振成像，该病人床独特地调节到每个患者体内静脉造影剂的传输。

DESCRIPTION (provided by applicant): The long term objective of this project continues to be the development of methods which permit MR data acquisition during continuous motion of the patient table for contrast-enhanced MR angiographic studies of the peripheral vasculature. This will allow diagnostic quality imaging of the vasculature from the abdomen and pelvis to the feet to allow diagnosis and characterization of peripheral vascular disease. Imaging during continuous table motion permits high efficiency in the use of scan time and of the contrast dose. Because a given axial level is imaged within the moving field-of-view for only a limited time, typically 20 sec or less, it is critical to allow improvements in spatial resolution for a given acquisition time. To this end, acceleration techniques demonstrated in Years 01-04 in one dimension will be extended to the two lateral dimensions. Another major aim of the study is to image the contrast dose transit in real time, automatically track its position, and use this information to automatically adjust the table velocity. The grant application includes the following specific aims: 1. High Resolution CE-MRA of a Fixed FOV Using 2D Acceleration Techniques. In preparation for imaging during continuous table motion, techniques will first be developed for performing highly accelerated acquisitions during no table motion within a targeted 16 sec. The elliptical centric view order will be combined with 2D homodyne, 2D SENSE, and time-resolved view-shared acquisition for 1 mm isotropic resolution. 2. Parallel Acquisition Techniques Applied During Continuous Table Motion. The accelerated acquisition methods of Aim #1 will be adapted to continuously moving table imaging. Reconstruction algorithms will be developed which account for gradient warping, 2D SENSE-homodyne, and variable FOV acquisition. Coils will be developed which allow efficient 15x accelerated 2D parallel acquisition over an extended FOV. 3. Patient-Specific Acquisition for Continuously Moving Table Peripheral MRA. Methods will be developed to detect the leading edge of the contrast bolus as it moves along the peripheral vasculature and then to use this information to alter the patient table motion in real time. This will be tested initially in phantoms and then using a test bolus. The final technique will be one in which an extended-FOV, high spatial resolution, arterial phase peripheral angiogram is formed by automatically tracking the full contrast bolus with no need for a test bolus. PUBLIC HEALTH RELEVANCE: Peripheral vascular disease is a major problem in the population of the United States, and it is important to image and diagnosis this condition in an easy, accurate, reliable, safe manner which not only accounts for patient-to-patient differences in anatomy and blood flow but also accommodates the long field of view which ex- tends from the abdomen to the feet. This project is relevant to this problem, as the goal is to develop a method which allows high spatial resolution MR imaging of the extended vasculature by using a moving patient table uniquely tuned to the transit of intravenous contrast material within each patient.