Improved SNR in Phase Contrast Velocimetry With Five-Point Balanced Flow Encoding
Improved SNR in Phase Contrast Velocimetry With Five-Point Balanced Flow Encoding
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DOI：
10.1002/mrm.22202
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发表时间：
2010-02-01
影响因子：
3.3
通讯作者：
Markl, Michael
中科院分区：
文献类型：
--
作者：
Johnson, Kevin M.;Markl, Michael
相位对比测速仪可以用来测量复杂的血流，对血管血流动力学进行定量和定性的评估。然而，相位对比度要求设置最大可测量速度，以平衡噪声和相位混叠。为了有效地降低相位对比度图像中的噪声，一些研究人员提出了扩展的速度编码方案，使用额外的编码来解开相位混叠；然而，现有的技术可能导致回声和扫描时间的显著增加，限制了它们的临床益处。在这项工作中，我们开发了一种新的五点速度编码方案，该方案在扫描和回波时间增加最小的情况下有效地降低了噪声。在模体中进行的研究表明，与标准的四点编码方案相比，速度噪声比增加了63%。在健康志愿者中进行了主动脉血流速度测量，显示出类似的速度噪声比改善。在这些志愿者中，还证明了在不牺牲精确度的情况下，低分辨率图像可以用于第五个编码点，将扫描时间损失从25%降低到不到1%。《医学评论》63：349-355,2010。(C)2010年Wiley-Liss公司
Phase contrast velocimetry can be utilized to measure complex flow for both quantitative and qualitative assessment of vascular hemodynamics. However, phase contrast requires that a maximum measurable velocity be set that balances noise and phase aliasing. To efficiently reduce noise in phase contrast images, several investigators have proposed extended velocity encoding schemes that use extra encodings to unwrap phase aliasing; however, existing techniques can lead to significant increases in echo and scan time, limiting their clinical benefits. In this work, we have developed a novel five-point velocity encoding scheme that efficiently reduces noise with minimal increases in scan and echo time. Investigations were performed in phantoms, demonstrating a 63% increase in velocity-to-noise ratio compared to standard four-point encoding schemes. Aortic velocity measurements were performed in healthy volunteers, showing similar velocity-to-noise ratio improvements. In those volunteers, it was also demonstrated that, without sacrificing accuracy, low-resolution images can be used for the fifth encoding point, reducing the scan time penalty from 25% down to less than 1%. Magn Reson Med 63:349-355, 2010. (C) 2010 Wiley-Liss, Inc.