Fig. 2

Reconstructed images with ROI and difference maps of an eight-channel phantom data. The acquisition is accelerated with a net reduction factor of 2.29. a Reference image with SoS reconstruction. b GRAPPA reconstruction with 64 ACS lines and 4 outer reduction factor. c GRAPPA reconstruction with 40 ACS lines and 3 outer reduction factor. d Reconstruction using Tikhonov regularization. e Reconstruction using IRLS method. f Reconstruction using AV-GRAPPA. g–k Difference maps of b–f, respectively. AV-GRAPPA is able to reconstruct the original reference image good. Other methods lose some fine structures and result in noise and aliasing artifacts