MRI phase contrast velocity and flow errors in turbulent stenotic jets
MRI phase contrast velocity and flow errors in turbulent stenotic jets
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DOI：
10.1002/jmri.21395
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发表时间：
2008-07-01
影响因子：
4.4
通讯作者：
Young, Alistair A.
中科院分区：
文献类型：
--
作者：
O'Brien, Kieran R.;Cowan, Brett R.;Young, Alistair A.
目的：为了澄清使用MRI相位对比（PC），作为一种替代多普勒超声心动图，测量高速湍流射流与狭窄性瓣膜diseases.Materials和方法：在体内PC主动脉每搏输出量（SV）与心室SV在31例中重度主动脉瓣狭窄（AS）进行了比较。两个在体外管道实验进行了稳定的狭窄和nonstenotic湍流flow.Results：在SV的平均误差在体内左心室（LV）流出道（LVOT）和-41%，41%，在主动脉根部进行评估的错误。误差在具有最高多普勒峰值速度的患者中最为突出。体外非狭窄流量实验显示流量测量准确，平均误差为1.8%。在体外狭窄血流中发现了显著误差，随着回波时间（TE）的缩短而减少：TE为4.8/4.0/3.3/2.2/2.0 msec时，平均误差为-166/-67/-25/-13/-8.8%。在这两个在体内和体外狭窄的实验中的错误与信号损失的流量补偿幅度images.Conclusion：信号损失与狭窄射流的流量误差。目前临床上可用的TE > 2 msec的PC脉冲序列可能无法准确量化严重病变的血流。
Purpose: To clarify the use of MRI phase contrast (PC), as an alternative to Doppler echocardiography, when measuring high-velocity turbulent jets associated with stenotic valvular disease.Materials and Methods: In vivo PC aortic stroke volume (SV) was compared with ventricular SV in 31 patients with moderate to severe aortic stenosis (AS). Two in vitro pipe experiments were conducted to evaluate errors in steady stenotic and nonstenotic turbulent flows.Results: The average in vivo error in SV was -24% in the left-ventricular (LV) outflow tract (LVOT) and -41% in the aortic root. Errors were most prominent in patients with the highest Doppler peak velocities. In vitro nonstenotic flow experiments showed accurate flow measurement with an average error of 1.8%. Significant errors were found in the in vitro stenotic flow, which reduced with shorter echo times (TE): average error -166/-67/-25/-13/-8.8% for TEs of 4.8/4.0/3.3/2.2/2.0 msec. In both the in vivo and in vitro stenotic experiments the errors were associated with signal loss in the flow-compensated magnitude image.Conclusion: Signal loss is associated with flow errors in stenotic jets. Current clinically available PC pulse sequences with TE > 2 msec may not accurately quantify flow for severe lesions.