Moving through K-Space by Point Reflections the TRASE Method

Jonathan C. Sharp¹, Scott B. King²

Standard MRI methods achieve a scanning of k-space by 2 methods: B0-gradients (providing continuous motion) and refocusing (point reflection about the k-space origin). Here we analyze a third option: point reflection about other k-space locations. The method is achieved by refocusing with B1-phase-gradients and is the basis of the TRASE (Transmit Array Spatial Encoding) imaging method. These novel k-space operations offer the pulse sequence designer an expanded toolkit. Our aim here is to formalize the rules governing the construction of k-space trajectories for this type of sequence.