On the nature and reduction of plaque-mimicking flow artifacts in black blood MRI of the carotid bifurcation
On the nature and reduction of plaque-mimicking flow artifacts in black blood MRI of the carotid bifurcation
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DOI：
10.1002/mrm.1910390417
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发表时间：
1998-04-01
影响因子：
3.3
通讯作者：
Rutt, BK
中科院分区：
文献类型：
--
作者：
Steinman, DA;Rutt, BK
正常人颈动脉分叉的心脏门控黑血MRI显示管腔内信号，提示管壁增厚或斑块形成。这一信号被认为是人为的，源于颈动脉分叉处存在的复杂血流模式。对颈动脉分叉模型的血流动力学和黑血多层图像采集的计算机模拟表明，这些伪影是由于自旋在颈动脉球慢而循环的血流中恢复信号而产生的。计算的血流动力学还表明，通过在峰值收缩后250毫秒的窗口内门控获取颈动脉球部最易出现伪影的切片，可以最大限度地减少或完全消除这些伪影。将这些预测应用于对正常志愿者的研究表明，在大多数情况下，只需改变图像采集到的心脏周期的相位，就可以消除黑血MRI中的这些流动伪影。饱和片的大小和位置对这些伪影的影响很小，这一观察结果表明，在整个心脏周期持续再循环的情况下，需要反转-恢复或球囊本身的预饱和来抑制它们。
Cardiac-gated black blood MRI of the carotid artery bifurcation in normal human subjects shows signal within the lumen suggesting wall thickening or atherosclerotic plaque. This signal was believed to be artifactual, arising from complex flow patterns present at the carotid bifurcation. Computer simulation of the hemodynamics and black blood multislice image acquisition in a model of the carotid bifurcation showed that these artifacts arise from spins recovering their signal within the slow, recirculating flow of the carotid bulb. The computed hemodynamics also suggested that these artifacts could be minimized or eliminated entirely by gating the acquisition of slices in the most artifact-prone region of the carotid bulb within a 250-ms window after peak systole. Application of these predictions to studies of normal volunteers showed that, in most cases, these flow artifacts in black blood MRI can be eliminated simply by altering the phase of the cardiac cycle to which the image acquisition is gated. The observation that the size and placement of the saturation slabs had little effect on these artifacts suggested that, in those cases in which recirculation persists throughout the cardiac cycle, either inversion-recovery or presaturation within the bulb itself would be required to suppress them.