用于7T颈椎脊髓成像的19通道接收阵列和4通道发射阵列线圈。
Nineteen-channel receive array and four-channel transmit array coil for cervical spinal cord imaging at 7T.
作者信息
Zhao Wei, Cohen-Adad Julien, Polimeni Jonathan R, Keil Boris, Guerin Bastien, Setsompop Kawin, Serano Peter, Mareyam Azma, Hoecht Philipp, Wald Lawrence L
机构信息
A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA.
出版信息
Magn Reson Med. 2014 Jul;72(1):291-300. doi: 10.1002/mrm.24911. Epub 2013 Aug 20.
PURPOSE
To design and validate a radiofrequency (RF) array coil for cervical spinal cord imaging at 7T.
METHODS
A 19-channel receive array with a four-channel transmit array was developed on a close-fitting coil former at 7T. Transmit efficiency and specific absorption rate were evaluated in a B1 (+) mapping study and an electromagnetic model. Receive signal-to-noise ratio (SNR) and noise amplification for parallel imaging were evaluated and compared with a commercial 3T 19-channel head-neck array and a 7T four-channel spine array. The performance of the array was qualitatively demonstrated in human volunteers using high-resolution imaging (down to 300 μm in-plane).
RESULTS
The transmit and receive arrays showed good bench performance. The SNR was approximately 4.2-fold higher in the 7T receive array at the location of the cord with respect to the 3T coil. The g-factor results showed an additional acceleration was possible with the 7T array. In vivo imaging was feasible and showed high SNR and tissue contrast.
CONCLUSION
The highly parallel transmit and receive arrays were demonstrated to be fit for spinal cord imaging at 7T. The high sensitivity of the receive coil combined with ultra-high field will likely improve investigations of microstructure and tissue segmentation in the healthy and pathological spinal cord.
目的
设计并验证一款用于7T场强下颈段脊髓成像的射频（RF）阵列线圈。
方法
在7T场强下，于一个紧密贴合的线圈架上开发了一个具有四通道发射阵列的19通道接收阵列。在B1（+）映射研究和电磁模型中评估了发射效率和比吸收率。评估了接收信噪比（SNR）和平行成像的噪声放大，并与一款商用3T 19通道头颈阵列和一款7T四通道脊柱阵列进行了比较。使用高分辨率成像（平面内低至300μm）在人体志愿者中定性展示了该阵列的性能。
结果
发射和接收阵列在实验台上表现良好。在脊髓位置，7T接收阵列的SNR相对于3T线圈高出约4.2倍。g因子结果表明7T阵列还可实现额外的加速。体内成像可行，显示出高SNR和组织对比度。
结论
高度并行的发射和接收阵列被证明适用于7T场强下的脊髓成像。接收线圈的高灵敏度与超高场强相结合，可能会改善对健康和病变脊髓的微观结构及组织分割的研究。
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