Each coil consists of two parts; a deep posterior segment, covering and a separate “frontal paddle” over the forehead (Fig. 1 ). The larger posterior section is designed, so the child can lie down into the coil (Fig. 2 ), rather than a helmet design, which must be pulled down over the head. The eyes and face are completely unobstructed to increase comfort and facilitate visual stimulation for functional studies or anesthesia ventilation if needed. The different helmet sizes were obtained from the surface contours of aligned three-dimensional MRI scans from 20 children of both sexes in each age group. The helmet shape was taken by dilating the 95th percentile contour to accommodate 3-mm foam padding. The final design of the helmet parts were printed in acrylonitrile butadiene styrene (ABS) plastic using a rapid prototyping three-dimensional printer (Dimension SST 1200es, Dimension, Inc., Eden Prairie, MN, USA). The posterior segment of the coil was mounted in a custom-made plastic housing to cover all electronic components and fit the head-end of the scanner’s patient bed.
The statistically obtained head contours were also used to print sized-matched head-shaped phantoms based on the 50% size contour. These phantoms were placed in the tightly fitted coil arrays and were used for coil adjustments at the bench, as well as for imaging evaluations in the MRI scanner.
The statistically obtained head contours were also used to print sized-matched head-shaped phantoms based on the 50% size contour. These phantoms were placed in the tightly fitted coil arrays and were used for coil adjustments at the bench, as well as for imaging evaluations in the MRI scanner.
