Rapid Single-Scan T2*-Mapping Using Exponential Excitation Pulses and Image-Based Correction for Linear Background Gradients
Rapid Single-Scan T2*-Mapping Using Exponential Excitation Pulses and Image-Based Correction for Linear Background Gradients
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DOI：
10.1002/mrm.21971
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发表时间：
2009-07-01
影响因子：
3.3
通讯作者：
Deichmann, Ralf
中科院分区：
文献类型：
--
作者：
Baudrexel, Simon;Volz, Steffen;Deichmann, Ralf
描述了一种基于多梯度回波（multi-GE）成像并校正静磁场不均匀性的快速定量T（2）* 标测方法，使用指数激励脉冲。从相位信息获得场梯度图，随后校正模量数据，允许简单的单指数T（2）* 拟合。由于场不均匀性而遭受主要信号损失的具有长回波时间的回波被排除在分析之外。矩阵尺寸为256 x 256、平面内分辨率为1 mm、层厚为2 mm时，每层的采集时间为15 s。对平面内场梯度的附加校正进一步提高了精度。体模实验表明，该方法提供了准确的T（2）* 值的磁场梯度高达200 μ T/m;梯度高达300 μ T/m的误差不超过15%。在健康志愿者身上在3 T下获得的体内T（2）* 值与文献结果非常一致。Magn Reson Med 62：263-268，2009. (C)2009威利-利斯公司
A method for fast quantitative T(2)* mapping based on multiple gradient-echo (multi-GE) imaging with correction for static magnetic field inhomogeneities is described, using an exponential excitation pulse. Field gradient maps are obtained from the phase information and modulus data are subsequently corrected, allowing for simple monoexponential T(2)* fitting. Echoes with long echo times suffering from major signal losses due to field inhomogeneities are excluded from the analysis. The acquisition time for a matrix size of 256 x 256, 1 mm in-plane resolution, and 2 mm slice thickness amounts to 15 s per slice. An additional correction for in-plane field gradients further improves accuracy. Phantom experiments show that the method provides accurate T(2)* values for field gradients up to 200 mu T/m; for gradients up to 300 mu T/m errors do not exceed 15%. In vivo T(2)* values acquired on healthy volunteers at 3T are in excellent agreement with results from the literature. Magn Reson Med 62:263-268, 2009. (C) 2009 Wiley-Liss, Inc.