Optimal Flip Angle for High Contrast Balanced SSFP Cardiac Cine Imaging
Optimal Flip Angle for High Contrast Balanced SSFP Cardiac Cine Imaging
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DOI：
10.1002/mrm.25228
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发表时间：
2015-03-01
影响因子：
3.3
通讯作者：
Ennis, Daniel B.
中科院分区：
文献类型：
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作者：
Srinivasan, Subashini;Ennis, Daniel B.
目的确定心脏电影成像的最佳翻转角（FA），以最大限度地提高心肌信号和血液-心肌对比度。方法将静止心肌和流动血液的Bloch方程模拟与不完美切片轮廓进行比较，以在短轴和四轴上测量健康受试者（N=10）的血液和心肌信噪比（SNR）和血液-心肌对比度-噪声比（CNR）。结果左心室（LV）和右心室（RV）的血液SNR和血液心肌CNR随着FA的增加而增加，在短轴视图中接近105度。在RV四腔视图中观察到类似的趋势，但是对于FA>75度，LV和RV血液之间出现显著的SNR差异，特别是在收缩期。显着的RV和LV SNR和CNR的差异也很明显，在三腔视图中，由于主要的LV平面内流与RV通过平面flow.ConclusionVery高的血液心肌CNR可以获得与FA约105度的短轴平面和约75度的三腔和四腔成像平面。然而，如果通过平面的流动受到限制，如对于具有低射血分数或低心率的患者可能发生的，则FA可以被限制为大约75度。Magn Reson Med 73：1095-1103，2015. (c)2014 Wiley Periodicals，Inc.
PurposeTo determine the optimal flip angle (FA) for cardiac cine imaging that maximizes myocardial signal and blood-myocardium contrast.MethodsBloch equation simulations of stationary myocardium and flowing blood with an imperfect slice profile were compared to in vivo measurements of blood and myocardium signal-to-noise ratio (SNR) and blood-myocardium contrast-to-noise ratio (CNR) in healthy subjects (N=10) in the short-axis and four-chamber views and in patients (N=7) in the three-chamber imaging plane.ResultsLeft ventricular (LV) and right ventricular (RV) blood SNR and blood-myocardium CNR increases with increasing FA up to approximate to 105 degrees in the short-axis view. A similar trend is seen in the RV four-chamber view, but a marked SNR difference between the LV and RV blood appears for FA>75 degrees, especially during systole. Notable RV and LV SNR and CNR differences are also evident in the three-chamber view due to the predominant LV in-plane flow versus RV through-plane flow.ConclusionVery high blood-myocardium CNR can be obtained with a FA of approximate to 105 degrees in the short-axis plane and approximate to 75 degrees in the three-chamber and four-chamber imaging planes. However, if through-plane flow is limited, as may occur for patients with low ejection fraction or low heart rates, then the FA may be limited to approximate to 75 degrees. Magn Reson Med 73:1095-1103, 2015. (c) 2014 Wiley Periodicals, Inc.