Spiral MR fingerprinting at 7 T with simultaneous B1 estimation
Spiral MR fingerprinting at 7 T with simultaneous B1 estimation
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DOI：
10.1016/j.mri.2017.04.003
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发表时间：
2017-09-01
影响因子：
2.5
通讯作者：
Tosetti, Michela
中科院分区：
文献类型：
--
作者：
Buonincontri, Guido;Schulte, Rolf F.;Tosetti, Michela
磁共振指纹图是一种有效的新的定量成像方法。我们的目标是将该技术扩展到成像体积内存在B1+不均匀的情况。以前的方法使用翻转角的突变来同时估计T1和T2的B1+场，在4.7T的小动物扫描仪中使用笛卡尔方法。在这里，我们评估了类似的方法是否适合于使用7T扫描仪的螺旋读数对人脑进行成像。我们发现，即使在极端情况下，我们的改进方案也可以显著减少B1+不均匀的不利影响，与文献方法相比，T2估计中的偏差和方差都减少了一个数量级。采集所用功率低于1.5W/kg SAR，每个切片可在12秒内完成采集。总之，我们的方法可以用来在短时间内对7T的大脑进行定量成像，同时估计B1+的分布。(C)2017 Elsevier Inc.保留所有权利。
Magnetic resonance fingerprinting is an efficient, new approach for quantitative imaging with MR. We aimed to extend this technique to cases with B1+ inhomogeneities within the imaging volume.Previous approaches have used abrupt changes in flip angles to estimate the B1+ field simultaneously with T1 and T2, using a Cartesian approach in a small-animal scanner at 4.7T. Here, we evaluated whether a similar approach would be suitable for imaging human brains using spiral readouts with a 7T scanner.We found that our modified scheme could significantly reduce the adverse effects of B1+ inhomogeneities even in extreme cases, reducing both the bias and the variance in T2 estimations by an order of magnitude when compared to literature methods. Acquisitions used less than 1.5W/kg SAR and could be performed in 12s per slice. In conclusion, our approach can be used to perform quantitative imaging of the brain at 7T in a short time, simultaneously estimating the B1+ profile. (C) 2017 Elsevier Inc. All rights reserved.