An 8-channel non-overlapped spinal cord array coil for 7T MR imaging

Introduction Surface coil arrays offer high sensitivity and large coverage that is particularly suitable for spinal cord MR imaging. To apply parallel imaging technique, sufficient decoupling among resonant element in coil arrays is required for independent signal detection and encoding. Although decoupling could be yielded between two overlapped coils, the increased g-factor in their overlapping area degrades the signal-to-noise ratio (SNR) of images. In this report, we designed and constructed an 8-channel non-overlapped surface coil array using with strong decoupling performance and good coverage for spine parallel imaging. Different from conventional decoupling methods for non-overlapping design such as the method using lumped L/C decoupling circuits (1, 2), we use a new magnetic-wall decoupling method to decouple the resonant elements. The magnetic wall is generated by the microstrip circuits positioned between two adjacent surface coil elements. Without physical connection between the decoupling microstrip and array elements, theoretically this method is not frequency-sensitive. Therefore the decoupling performance can be maintained in a broad frequency range. Bench test and preliminary imaging results are shown using the proposed coil array at 7T.