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允许在患者桌子连续运动期间获取MR数据的方法，用于周围血管系统的对比增强MR血管造影研究。这将有助于对从腹部、骨盆到足部的血管系统进行诊断质量成像，从而对周围血管疾病进行诊断和表征。在连续台运动期间成像允许高效率地使用扫描时间和造影剂剂量。由于给定的轴向水平在移动视场内成像的时间有限，通常为20秒或更短，因此在给定的采集时间内提高空间分辨率至关重要。为此，01-04学年在一维上演示的加速技术将扩展到两个横向维度。研究的另一个主要目的是实时成像造影剂传输，自动跟踪其位置，并利用这些信息自动调整表速度。拨款申请包括以下具体目标：使用二维加速技术的固定视场高分辨率CE-MRA。为了在连续工作台运动期间进行成像准备，将首先开发在目标16秒内无工作台运动期间执行高加速采集的技术。椭圆中心视图顺序将与2D同差、2D SENSE和时间分辨视图共享采集相结合，各向同性分辨率为1mm。2. 并行采集技术在连续表运动中的应用。Aim #1的加速采集方法将适用于连续移动台成像。重建算法将开发，其中考虑梯度扭曲，2D感同差，和可变视场采集。将开发线圈，允许在扩展视场上有效地加速15倍的2D并行采集。3. 连续移动桌周边MRA的患者特异性采集。当造影剂沿着周围血管运动时，检测造影剂前沿的方法将被开发出来，然后利用这些信息实时改变患者的桌面运动。这将首先在幻影中进行测试，然后使用测试丸。最后一种技术将是通过自动跟踪全造影剂而无需测试剂来形成大视场、高空间分辨率、动脉期外周血管造影。

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.