Phase Contrast Imaging using Isotropic Projection

描述（由申请人提供）：我们最近开发了一种各向同性角投影采集技术（VIPR），其允许用于感兴趣的对比信号占主导地位的情况的大的角欠采样因子。该技术是特别有前途的相衬（PC）成像，其中出色的背景抑制消除非血管条纹伪影。VIPR的高速可用于产生几种PC实现，当使用大成像体积时，其速度比传统PC快4-25倍，并且扫描时间和各向同性空间分辨率与3D飞行时间（TOF）相当。我们希望测试以下假设：3D VIPR-PC可以提供等同于甚至优于3D TOF的解剖信息，同时还提供了在3D体积中回顾性测量所有主要血管中的血流的机会，其准确性与多次2D PC扫描相当。我们提出了VIPR-PC的三种实现方式：（1）基本VIPR-PC版本，其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。我们将测试其回顾性测量成像体积中所有血管的平均流量的能力。为了提供解剖信息，还将其与3D TOF进行比较。(2)一种速度分辨非门控方法，用于提供体素内的速度和速度分布，并用于生成比使用单个VENC可获得的SNR更高的血管造影图像，以及（3）心脏相位分辨（CINE）版本，用于提供在大FOV中回顾性确定所有血管内的血流波形的机会，而无需为每个血管采集单独的2D扫描。我们建议开发和优化所提出的方法，并测试其可行性，使用模拟，幻影，并使用志愿者和患者的一系列研究。

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.