A Novel Method of Insert Gradient Field Mapping on a Composite Gradient System

Glen Morrell¹, Joshua Kaggie², K. C. Goodrich², Seong-Eun Kim², Sung Man Moon², Dennis Parker²

We demonstrate a method of mapping the field patterns of insert gradient coils in a composite gradient system. Composite gradient systems allow the simultaneous use of whole body gradient coils and localized insert gradient coils within the same pulse sequence. These systems combine the speed of nonlinear local insert gradient coils for readout with the desirable linearity of slower whole body gradients for slice selection. Correction of image distortion requires accurate maps of the nonlinear insert gradient fields used for readout. Our method provides distortion-free maps of the gradient insert fields over the entire imaging volume in reasonable imaging time