Limits to the accuracy of vessel diameter measurement in MR angiography
Limits to the accuracy of vessel diameter measurement in MR angiography
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DOI：
10.1002/jmri.1880080608
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发表时间：
1998-11-01
期刊：
影响因子：
--
通讯作者：
Viergever, MA
中科院分区：
文献类型：
--
作者：
Hoogeveen, RM;Bakker, CJG;Viergever, MA
这项工作解决了由MRI过程施加的基本限制的准确性与血管直径和横截面积可以从飞行时间（TOF）和相位对比（PC）MR源图像。通过模拟和体外实验，它表明，即使在没有现在相关的伪影，严重的不准确性，在确定的直径或横截面积可能会发生仅仅是因为物理过程的MR图像采集。分辨率和管腔内饱和度对血管外观有很大影响，因此对直径估计误差有很大影响。结果表明，低分辨率导致直径高估或甚至低估，管腔内饱和导致严重低估，即使相对较低的翻转角。速度和速度编码对PC图像中的管腔外观没有重大影响。只有当管腔直径构成TOF和PC采集的至少三个像素时，才能获得准确的直径估计，前提是抑制或避免管腔内饱和。此外，由于TOF和PC图像的构成不同，因此应不同地分析管腔以获得准确的直径和横截面积。
This work addresses the fundamental limits imposed by the MRI process on the accuracy with which vessel diameters and cross-sectional areas can be derived from time-of-flight (TOF) and phase-contrast (PC) MR source images. By means of simulations and in vitro experiments, it is demonstrated that, even in the absence of now-related artifacts, severe inaccuracies in the determination of diameters or cross-sectional areas may occur solely because of the physical process of the MR image acquisition. Resolution and intraluminal saturation have strong effects on the vessel appearance and thus on the diameter estimation error. It is shown that low resolution leads to diameter overestimation or even underestimation and that intraluminal saturation causes severe underestimation, even for relatively low flip angles. Velocity and velocity encoding do not have a major influence on lumen appearance in PC images. Accurate diameter estimations can be attained only if lumen diameters constitute at least three pixels for both TOF and PC acquisitions, provided that intraluminal saturation is suppressed or avoided. Additionally, since the constitution of TOF and PC images is dissimilar, lumina should be analyzed differently to obtain accurate diameters and cross-sectional areas.