Quantification of intravoxel velocity standard deviation and turbulence intensity by generalizing phase-contrast MRI
Quantification of intravoxel velocity standard deviation and turbulence intensity by generalizing phase-contrast MRI
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DOI：
10.1002/mrm.21022
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发表时间：
2006-10-01
影响因子：
3.3
通讯作者：
Ebbers, Tino
中科院分区：
文献类型：
--
作者：
Dyverfeldt, Petter;Sigfridsson, Andreas;Ebbers, Tino
以速度波动为特征的湍流是多种心血管疾病发病机制的促成因素。然而，缺乏用于评估湍流的临床非侵入性工具。众所周知，在磁梯度矩的影响期间在体素内出现多个自旋速度会导致相位对比磁共振成像（PC-MRI）中的信号损失。在本文中，一个数学推导的表达式，用于计算标准偏差（SD）的血流速度分布在一个体素。SD是从用不同的第一梯度矩采集的PC-MRI信号的幅度获得的。该方法利用湍流强度与湍流速度之间的关系，可以对湍流进行定量研究。为了验证，在体外流动体模中的TI进行了量化，并且结果与先前发表的激光多普勒风速仪（LDA）结果相比有利。这种方法有可能成为一个重要的工具，在动脉树湍流的非侵入性评估。
Turbulent flow, characterized by velocity fluctuations, is a contributing factor to the pathogenesis of several cardiovascular diseases. A clinical noninvasive tool for assessing turbulence is lacking, however. It is well known that the occurrence of multiple spin velocities within a voxel during the influence of a magnetic gradient moment causes signal loss in phase-contrast magnetic resonance imaging (PC-MRI). In this paper a mathematical derivation of an expression for computing the standard deviation (SD) of the blood flow velocity distribution within a voxel is presented. The SD is obtained from the magnitude of PC-MRI signals acquired with different first gradient moments. By exploiting the relation between the SD and turbulence intensity (TI), this method allows for quantitative studies of turbulence. For validation, the TI in an in vitro flow phantom was quantified, and the results compared favorably with previously published laser Doppler anemometry (LDA) results. This method has the potential to become an important tool for the noninvasive assessment of turbulence in the arterial tree.