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），该技术允许大角度欠采样因子用于感兴趣的对比信号占主导地位的情况。该技术特别有希望用于相衬成像（PC），因为出色的背景抑制消除了非血管条纹伪影。高速的VIPR可用于生产比传统PC快4-25倍的PC实现，当使用大成像体积时，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。我们希望验证这样一个假设，即3D VIPR-PC可以提供相当于甚至有时比3D TOF更好的解剖信息，同时也提供了在3D体积中回顾性测量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。我们提出了三种VIPR-PC实现方案：(1)基本VIPR-PC版本，它将使用单一速度编码（VENC），并提供比传统3DPC更高的空间分辨率。我们将测试其在成像容积内测量所有血管平均流量的能力。为了提供解剖学信息，它还将与3D TOF进行比较。(2)速度分辨非门控方法，用于提供体素内的速度和速度分布，并生成比单个VENC具有更高信噪比的血管造影图像；(3)心脏相位分辨（CINE）版本，提供回顾性确定大视场中所有血管内的血流波形的机会，而无需对每个血管进行单独的2D扫描。我们建议开发和优化所提出的方法，并通过模拟，幻影和一系列志愿者和患者的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.