Linear Image Reconstruction Technique for MRI with Nonlinear Encoding Fields (Part II) – O-Space Imaging (LIRT-OSI)

Motivation: The extremely time-consuming iterative algebraic reconstruction techniques(ART), e.g., Kaczmarz, have been used for image reconstruction in MRI with nonlinear encoding fields, e.g., O-space imaging (OSI). Goal(s): We evaluate the effectiveness and performance of the linear image reconstruction technique (LIRT) for MRI with nonlinear encoding fields with an application of image reconstruction for O-space imaging (OSI). Approach: The rotation theorem and linearity of 2D Fourier Transform lay the theoretical basis for LIRT image reconstruction for OSI. Results: We compared the computation time of LIRT with SART for OSI image reconstruction. The final reconstructed images show no visually perceived non-linear distortion for OSI. Impact: LIRT-OSI further demonstrate how LIRT can be accommodated to a wide range of nonlinear MRI field systems for quick image reconstruction and assessment, which is the first time such a technique has been proposed to the best of our knowledge.