Simultaneous variable flip angle-actual flip angle imaging method for improved accuracy and precision of three-dimensional T1 and B1 measurements
Simultaneous variable flip angle-actual flip angle imaging method for improved accuracy and precision of three-dimensional T1 and B1 measurements
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DOI：
10.1002/mrm.23199
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发表时间：
2012-07-01
影响因子：
3.3
通讯作者：
Samsonov, Alexey A.
中科院分区：
文献类型：
--
作者：
Hurley, Samuel A.;Yarnykh, Vasily L.;Samsonov, Alexey A.
基于实际翻转角(FA)成像和可变翻转角(FA)方法的结合，提出了一种新的同时定位T1和B1的高效、准确的http://runonce.msn.com/runonce3.aspx技术。可变FAActual FA成像利用单个实际FA成像和一个或多个被破坏的梯度回波采集以及同时的非线性拟合过程来产生准确的T1/B1图。可变FAActual FA成像的优点是在实际FA成像序列中，无论是短T1时间还是长重复时间，都具有很高的精度。仿真结果表明，在重复时间与T1时间之比为0.010.45的范围内，该方法在FA中的精度为0.03%，在T1中的精度为0.07%。对于脑成像的情况，我们表明，只使用一个小的FA破坏的梯度回波采集就足够了，这导致了与原始可变FA方法相比，降低了破坏要求并显著减少了扫描时间。活体验证产生了高质量的3DT1图和T1测量，在先前公布的值的10%内，在临床可接受的扫描时间内。可变FAActual FA成像方法将提高许多需要T1/B1成像的定量MRI方法的准确性和临床可行性，如动态对比增强灌注成像和定量磁化传递成像。Magn Reson Med，2012。(C)2011年威利期刊公司。
A new time-efficient and accurate technique for simultaneous mapping of T1 and B1 ishttp://runonce.msn.com/runonce3.aspx proposed based on a combination of the actual flip angle (FA) imaging and variable FA methods. Variable FAactual FA imaging utilizes a single actual FA imaging and one or more spoiled gradient-echo acquisitions with a simultaneous nonlinear fitting procedure to yield accurate T1/B1 maps. The advantage of variable FAactual FA imaging is high accuracy at either short T1 times or long repetition times in the actual FA imaging sequence. Simulations show this method is accurate to 0.03% in FA and 0.07% in T1 for ratios of repetition time to T1 time over the range of 0.010.45. We show for the case of brain imaging that it is sufficient to use only one small FA spoiled gradient-echo acquisition, which results in reduced spoiling requirements and a significant scan time reduction compared to the original variable FA method. In vivo validation yielded high-quality 3D T1 maps and T1 measurements within 10% of previously published values and within a clinically acceptable scan time. The variable FAactual FA imaging method will increase the accuracy and clinical feasibility of many quantitative MRI methods requiring T1/B1 mapping such as dynamic contrast enhanced perfusion and quantitative magnetization transfer imaging. Magn Reson Med, 2012. (c) 2011 Wiley Periodicals, Inc.