A Printed Loop Element with Integrated Capacitors and Co-Planar Shield for 7 Tesla

INTRODUCTION Shielded RF coils have been investigated since the earliest days of MRI, taking the form of the “Zabel coil” [1] a shielded transmission line coil, coils over ground planes, and more recently microstrip coils, particularly for use at high-fields [2]. Some authors have stated that RF shields are essential for 7T surface coils over 10 cm in diameter [3], and others have successfully built smaller loops as array elements without using shields [4], consistent with this guideline. This abstract examines the effectiveness of a co-planar shield at 7T. The co-planar shielding configuration may be particularly advantageous in constructing array coils, particularly when paired with coils using the distributed capacitance of dual-sided PC boards.