C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.
Carle Foundation Hospital, Urbana, IL, USA.
Magn Reson Med. 2020 Sep;84(3):1672-1677. doi: 10.1002/mrm.28215. Epub 2020 Feb 12.
Imaging the carotid arteries at 7T ideally requires a flexible multichannel array that allows B1-shimming and conforms to different neck sizes. The major challenge is to minimize coupling between closely spaced coils and to make the coupling relatively insensitive to loading conditions.
We have designed a five-channel flexible transceive array composed of shielded-coaxial-cable coils placed on the anterior part of the neck and conforming to the anatomy. In vivo imaging of the carotid arteries in three subjects has been performed.
The measured noise correlation matrices show the decoupling level between the individual elements to be -12.5 dB and better. Anatomical localizer imaging of the carotids shows both carotids in every subject well visualized after B1-shimming. In vivo black-blood, carotid images were acquired with very high in-plane spatial resolution (0.25 × 0.25 mm ) with clear depiction of the vessel walls.
The flexibility of the proposed coil has been demonstrated by imaging subjects with different neck circumferences. To the best of our knowledge, the in-plane resolution of 0.25 × 0.25 mm is the highest reported at 7T.
在 7T 下对颈动脉进行成像，理想情况下需要使用灵活的多通道阵列，该阵列允许进行 B1 匀场并与不同的颈部尺寸相适应。主要的挑战是最小化近距离放置的线圈之间的耦合，并使耦合相对不受负载条件的影响。
我们设计了一个由放置在颈部前侧并与解剖结构相适应的屏蔽同轴线缆线圈组成的五通道柔性收发阵列。对三位受试者的颈动脉进行了体内成像。
测量的噪声相关矩阵显示，各单元之间的解耦水平达到-12.5dB 及以上。对颈动脉的解剖定位成像显示，在 B1 匀场后，每位受试者的双侧颈动脉均能很好地可视化。采用非常高的平面内空间分辨率（0.25×0.25mm）获得了体内黑血颈动脉图像，能够清晰地描绘血管壁。
通过对不同颈围的受试者进行成像，证明了所提出的线圈的灵活性。据我们所知，0.25×0.25mm 的平面内分辨率是在 7T 下报道的最高分辨率。
