An improved element design for 64‐channel planar imaging

Abstract

Investigation of highly accelerated MRI has developed into a lively corner in the hardware and methodology arena in recent years. At the extreme of (one-dimensional) acceleration, our group introduced Single Echo Acquisition (SEA) imaging, in which the need to phase encode a 64×Nreadout image is eliminated and replaced with the well-localized spatial information obtained from an array of 64 very narrow, long, parallel coils. The narrow coil width (2mm) that facilitates this is accompanied by a concomitant constraint on the useful imaging depth. This note describes a 64-element planar array, constructed within the same 8×13cm total footprint as the original SEA array, still enabling full acceleration in one dimension, but with an element design modified to increase the imaging depth. This was accomplished by lowering the outer conducting legs of the planar pair with respect to the center conductor and adding a geometric decoupling configuration away from the imaging field of view. The element has been called a dual-plane pair in that the current carrying rungs in the imaging FOV function exactly as the planar pair, but are simply placed in two separate planes (sides of PCB in this case).

Massively parallel MRI detector arrays

“…Thus, the gradients account for as little as 10% of the encoding; the rest of the burden being placed on the receive array. While the “ultimate” g-factor theory tells us there are limits to the ability of arrays to encode, primarily from the fundamental smoothness of solutions to Maxwell’s equations as you penetrate deeply into the object [34,35,37], planar 64-channel arrays in the very near field show that there is virtually no limit to using the spatial information of the arrays to encode [96–98]. Figure 12 shows a high resolution (1mm × 1mm × 2mm) spin echo EPI brain image acquired with a 96-channel array at accelerations of R =4,5,6, and 8×, demonstrating the ability of the array to achieve its expected acceleration in one dimension ( R ~6), which is relatively near the expected limit of 1-D acceleration.…”

Eight-channel transmit/receive head array for use with ultra-low output impedance amplifiers

“…In choosing an appropriate element design, loop elements, dual plane pair elements [8], and a rung element were considered. The array was intended to be used in a transmit/receive configuration, using the add-on eight channel prototype transmit system and the existing GE eightchannel receiver.…”