A Flexible 32-channel Receive Array Combined With a Homogeneous Transmit Coil for Human Lung Imaging With Hyperpolarized 3He at 1.5 T
A Flexible 32-channel Receive Array Combined With a Homogeneous Transmit Coil for Human Lung Imaging With Hyperpolarized 3He at 1.5 T
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DOI：
10.1002/mrm.22962
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发表时间：
2011-12-01
影响因子：
3.3
通讯作者：
Wild, Jim M.
中科院分区：
文献类型：
--
作者：
Deppe, Martin H.;Parra-Robles, Juan;Wild, Jim M.
并行成像为超极化核的MRI提供了一种有前途的方法，因为H-1 MRI通常由于采集时间减少而遇到的信噪比损失可以通过增加翻转角来抵消。超极化MRI的信噪比通常表现出对翻转角的强烈依赖性，这使得均匀的B-1（+）发射场是理想的。本文介绍了一种用于1.5T下3 He人肺成像的柔性32通道接收阵列，该阵列设计用于插入非对称鸟笼发射线圈。虽然32通道阵列允许在高加速因子下并行成像，但鸟笼式发射线圈提供均匀的B-1（+）场。阵元之间的解耦是通过使用同心屏蔽的方法与同轴去耦。发射线圈和阵列元件之间的耦合由于低几何耦合系数而低，该低几何耦合系数通过阵列中的同心屏蔽进一步减小。32通道阵列和鸟笼发射线圈的组合提供了在加速因子R = 2和R = 4时具有相似信噪比的高质量He-3通气图像，同时保持均匀的B-1（+）。Magn Reson Med 66：1788-1797，2011。(C)2011 Wiley Periodials，Inc.
Parallel imaging presents a promising approach for MRI of hyperpolarized nuclei, as the penalty in signal-to-noise ratio typically encountered with H-1 MRI due to a reduction in acquisition time can be offset by an increase in flip angle. The signal-to-noise ratio of hyperpolarized MRI generally exhibits a strong dependence on flip angle, which makes a homogeneous B-1(+) transmit field desirable. This paper presents a flexible 32-channel receive array for 3 He human lung imaging at 1.5T designed for insertion into an asymmetric birdcage transmit coil. While the 32-channel array allows parallel imaging at high acceleration factors, the birdcage transmit coil provides a homogeneous B-1(+) field. Decoupling between array elements is achieved by using a concentric shielding approach together with preamplifier decoupling. Coupling between transmit coil and array elements is low by virtue of a low geometric coupling coefficient, which is reduced further by the concentric shields in the array. The combination of the 32-channel array and birdcage transmit coil provides He-3 ventilation images of excellent quality with similar signal-to-noise ratio at acceleration factors R = 2 and R = 4, while maintaining a homogeneous B-1(+). Magn Reson Med 66:1788-1797, 2011. (C) 2011 Wiley Periodials, Inc.