Phase Contrast Imaging using Isotropic Projection

描述(申请人提供)：我们最近开发了一种各向同性角度投影采集技术(VIPR)，该技术允许在感兴趣的对比度信号占主导地位的情况下使用大角度欠采样系数。这项技术特别适用于相位对比(PC)成像，因为出色的背景抑制消除了非血管条纹伪影。VIPR的高速可用于生产多个PC实现，在使用大成像体积时比传统PC快4-25倍，扫描时间和各向同性空间分辨率可与3D飞行时间(TOF)相媲美。我们希望验证这一假设，即3D VIPR-PC可以提供与3D TOF相同的解剖学信息，有时甚至优于3D TOF，同时还提供了回顾测量3D体积中所有主要血管血流的机会，其准确性可与多次2D PC扫描相媲美。我们提出了VIPR-PC的三种实现：(1)基本的VIPR-PC版本，它将使用单一速度编码(Venc)，并提供比传统3DPC显著更高的空间分辨率。我们将测试它回溯测量成像体积中所有血管的平均血流的能力。为了提供解剖学信息，它还将与3D TOF进行比较。(2)一种速度分辨的非门控方法，用于提供体素内的速度和速度分布，并用于生成具有比单个静脉静脉可获得的更高SNR的血管造影图像，以及(3)心脏相位分辨(Cine)版本，其提供了在大视野中回溯确定所有血管内的流动波形的机会，而不需要为每个血管获取单独的2D扫描。我们建议开发和优化所提出的方法，并使用模拟、幻影和使用志愿者和患者的一系列研究来测试其可行性。

DESCRIPTION (provided by applicant): We have recently developed an isotropic angular projection acquisition technique (VIPR) that allows for large angular undersampling factors for situations in which the contrast signals of interest dominate. The technique is especially promising for phase contrast (PC) imaging where the excellent background suppression eliminates non-vascular streak artifacts. The high speed of VIPR can be used to produce several PC implementations 4-25 times faster than conventional PC when large imaging volumes are used and with scan times and isotropic spatial resolution comparable to 3D Time-of Flight (TOF). We wish to test the hypothesis that 3D VIPR-PC can provide anatomical information equivalent to and sometimes better than 3D TOF while also providing the opportunity for retrospective measurement of flow in all major vessels in the 3D volume with accuracy comparable to multiple 2D PC scans. We propose three implementations of VIPR-PC: (1) A Basic VIPR-PC version that will use a single velocity encoding (VENC) and provide significantly higher spatial resolution than conventional 3DPC. We will test its ability to measure average flow retrospectively for all vessels in the imaging volume. It will also be compared to 3D TOF for the purpose of providing anatomical information. (2) A velocity resolved non-gated method for providing velocity and speed distributions within voxels and for generation of angiographic images which have higher SNR than obtainable with a single VENC, and (3) A cardiac phase-resolved (CINE) version to provide the opportunity for retrospective determination of flow waveforms within all vessels in a large FOV without the need to acquire separate 2D scans for each vessel. We propose to develop and optimize the proposed methods and to test their feasibility using simulations, phantoms, and a series of studies using volunteers and patients.