Synthetic T1-weighted brain image generation with incorporated coil intensity correction using DESPOT1
Synthetic T1-weighted brain image generation with incorporated coil intensity correction using DESPOT1
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DOI：
10.1016/j.mri.2006.03.015
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发表时间：
2006-11-01
影响因子：
2.5
通讯作者：
Peters, Terry M.
中科院分区：
文献类型：
--
作者：
Deoni, Sean C. L.;Rutt, Brian K.;Peters, Terry M.
在磁共振成像中越来越多地使用相控阵列和表面线圈，推动增加场强以及在临床试验期间需要跨多个部位的标准化成像，导致需要能够确保图像内和跨多个受试者/部位的强度一致性的方法。在这里，我们描述了一种手段，解决这些问题，通过扩展的快速T-1映射技术驱动的平衡单脉冲观测的T-1。所提出的方法的有效性进行了评估，使用人脑T-1地图在1.5 T与多通道相控阵线圈。通过将T-1值代入控制信号强度方程，同时假设平衡磁化强度为恒定值，重建校正的“合成”T-1加权图像。为了证明纵向研究中的信号正常化，我们从同一健康受试者在四个不同时间点获得的数据计算合成T-1加权图像。比较采集图像和合成图像之间的信号强度分布，以确定我们提出的方法的改进。校正后，图像显示出明显的质量改善，整个图像的信号均匀性增加。在整个纵向研究中也观察到近乎完美的信号归一化，允许图像之间的直接比较。此外，我们观察到的对比度噪声比增加（与常规的T-1加权图像相比）的合成图像创建，假设均匀的质子密度在整个体积。所提出的方法允许快速校正信号强度不均匀性，而不会显着延长检查时间或降低图像信噪比。该技术还提供了一种稳健的信号归一化方法，可用于疾病进展的多中心纵向MR研究，并允许用户使用任意T-1加权重建T-1加权图像。(c)2006年爱思唯尔公司All rights reserved.
The increased use of phased-array and surface coils in magnetic resonance imaging, the push toward increased field strength and the need for standardized imaging across multiple sites during clinical trials have resulted in the need for methods that can ensure consistency of intensity both within the image and across multiple subjects/sites. Here, we describe a means of addressing these concerns through an extension of the rapid T-1 mapping technique - driven equilibrium single-pulse observation of T-1. The effectiveness of the proposed approach was evaluated using human brain T-1 maps acquired at 1.5 T with a multichannel phased-array coil. Corrected "synthetic" T-1-weighted images were reconstructed by substituting the T-1 values back into the governing signal intensity equation while assuming a constant value for the equilibrium magnetization. To demonstrate signal normalization across a longitudinal study, we calculated synthetic T-1-weighted images from data acquired from the same healthy subject at four different time points. Signal intensity profiles between the acquired and synthetic images were compared to determine the improvements with our proposed approach. Following correction, the images demonstrate obvious qualitative improvement with increased signal uniformity across the image. Near-perfect signal normalization was also observed across the longitudinal study, allowing direct comparison between the images. In addition, we observe an increase in contrast-to-noise ratio (compared with regular T-1-weighted images) for synthetic images created, assuming uniform proton density throughout the volume. The proposed approach permits rapid correction for signal intensity inhomogeneity without significantly lengthening exam time or reducing image signal-to-noise ratio. This technique also provides a robust method for signal normalization, which is useful in multicenter longitudinal MR studies of disease progression, and allows the user to reconstruct T-1-weighted images with arbitrary T-1 weighting. (c) 2006 Elsevier Inc. All rights reserved.