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. Author manuscript; available in PMC: 2015 May 1.
Published in final edited form as: Magn Reson Med. 2013 Jul 2;71(5):1760–1770. doi: 10.1002/mrm.24840

Figure 7.

Figure 7

The un-regularized SPIRiT reconstruction (a) and difference image (b) for data set #1 with R ≈ 4 Poisson-disc undersampling and 13 dB input SNR display significant noise, while L1-SPIRiT with WMSE-optimal (e,f), WSURE-optimized (i,j), and L-curve-selected (m,n) choices of γ effectively improve image quality by nearly the same amount. The L-curve-based method results in a slightly oversmoothed image, although the difference is not as apparent as for the DESIGN reconstruction. Similar conclusions can be inferred from the second data set with R ≈ 4 Poisson-disc undersampling and 14 dB input SNR. The SPIRiT reconstruction (c,d) is relatively noisy, while L1-SPIRiT with WMSE-optimal (g,h), WSURE-optimized (k,l), and L-curve-selected (o,p) choices of γ all denoise the image while avoiding substantial oversmoothing. The difference images are displayed at 5× scale.