T2 restoration and noise suppression of hybrid MR images using wiener and linear prediction techniques

摘要

Hybrid imaging (HI) sequences used for magnetic resonance (MR) imaging and inherently degraded by T2 effects and additive measurement noise are enhanced. Wiener filter and linear prediction (LP) technique is used to process HI MR signals in the spatial frequency domain (K-space) and the hybrid domain respectively. Based on the average amplitude symmetry constraint of the spin echo signal, the amplitude frequency response function of the T2 distortion is estimated and used in the Weiner filter for a global T2 amplitude restoration. Then a linear prediction technique is utilized to obtain local signal amplitude and phase estimates around discontinuities of the frequency response function of the equivalent T2 distortion filter. These estimates are used to make local amplitude and phase corrections. The effectiveness of this combined technique in correction T2 distortion and reducing the measurement noise is analyzed and demonstrated using experiments on both phantoms and humans.