A wavelet-based super-resolution method for multi-slice MRI

Abstract

In multi-slice magnetic resonance imaging (MRI), the resolution in the slice direction is usually reduced to allow faster acquisition times and to reduce the amount of noise in each 2D slice. To address this issue, a number of super resolution (SR) methods have been proposed to improve the resolution of 3D MRI vol-umes. Most of the methods involve the use of prior models of the MRI data as regularization terms in an ill-conditioned inverse problem. The use of user-de-fined parameters produces better results for these approaches but an inappropriate choice may reduce the overall performance of the algorithm. In this pa-per, we present a wavelet domain SR method which uses a Gaussian scale mixture (GSM) model in a sparseness constraint to regularize the ill-posed SR inverse problem. The proposed approach also makes use of an extension of the Dual Tree Complex Wave-let Transform to provide the ability to analyze the wavelet coefficients with sub-level precision. Our re-sults show that the 3D MRI volumes reconstructed using this approach have quality superior to volumes produced by the best previously proposed appro-aches.