Design and construction of a prototype high-power B0 insert coil for field-cycled imaging in superconducting MRI systems

Field‐cycled MRI provides a noninvasive quantification of the concentration of bound (activated) targeted contrast agents. For field‐cycled imaging to be performed within a clinical full‐body superconducting MRI magnet, an auxiliary insertable magnet is required that can dynamically change the main field strength during the MR pulse sequence. Herein, the design and construction of a solenoidal insert coil is discussed. Design aspects including active shielding, thermal performance, forces, and ramping times are examined. Proper materials, construction methods, and interfacing for the insert coil with a clinical MRI are also covered. Finally, a field‐cycled experiment in a 1.5 T clinical MRI system is described, demonstrating the feasibility of this method and then future novel contrasts available with field‐cycled MRI. © 2009 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 35B: 1–10, 2009