Image Encoding With Blipped Gradients in an Echo Train

Purpose An MRI scanner was designed and built to encode ‐space points in the spin echoes occurring between pulses in an echo train by using blipped gradient pulses applied just prior to those spin echoes. Methods The proposed MRI scanner is a modification of an original design that used TRansmit Array Spatial Encoding (TRASE), a built‐in gradient, and a thin RF coil defining a single axial slice. However, for TRASE, the thin profile coil needed a spatially uniform phase, and this proved difficult to achieve. We therefore replaced the RF encoding coil with a low‐power gradient coil. This removed the need for a uniform spatial phase for the single slice RF coil to achieve Fourier image encoding. The pulse sequence then sent all transmit RF pulses through the one remaining single slice RF coil with gradient pulses applied between the RF pulses. The spin echoes between the RF pulses were received and used to define the ‐space points in one transverse direction. Image encoding in the perpendicular transverse direction was accomplished via frequency encoding within the built‐in transverse gradient. Mineral oil phantoms were used to establish a proof‐of‐concept for the blipped‐gradient imaging approach. Results The phantom images give a proof‐of‐concept level verification of the blipped‐gradient MRI design. Conclusion With work to address engineering imperfections, a blipped‐gradient approach could be used to achieve the extreme Size, Weight, and Power (SWaP) requirements for a spaceworthy MRI.