90-channel MR head coil delivers high-resolution images at 1.5T

A turbo spin-echo 1.5T image of the brain demonstrates 0.4 x 0.4-mm in-plane resolution and a 3-mm slice thickness. The image was obtained using a 90-channel phased- array head coil developed at the MGH Martinos Center for Biomedical Imaging in Charlestown, MA. The coil consists of a close-fitting fiberglass helmet with 90 overlapping 48-mm-diameter circular surface coils.

The coil, designed and built by research fellow Graham Wiggins, Ph.D., and Martinos Center director Larry L Wald, Ph.D., is being used in conjunction with a Siemens Avanto MR scanner. The 32 receive channels built into the Avanto are supplemented by two additional sets of receivers and image reconstruction computers, providing a total of 96 receive channels.

Several variations on the coil design are being used at MGH to deliver high-resolution anatomical imaging, particularly in cortical thickness studies relevant to Alzheimer's disease. These coils also show promise as means for substantially reducing scan time through the use of parallel imaging. The high number of elements allows for high acceleration factors in parallel imaging techniques. The close-fitting design and the small size of the individual receive elements also provide high SNR compared with other commercially available coils, particularly in the cortex. (Provided by Siemens Medical Solutions)