Fig 5.

Relative (parallel acquisition technique [PAT] R = 2 / R1-PPF) signal-to-noise ratio (SNR) measurements (mean ± SD) of mSENSE or GRAPPA R = 2 for 3 brain regions in 5 normal subjects. SNR values were fairly close between mSENSE and GRAPPA R = 2 methods for the 3 structures evaluated. Relative SNR values were reduced by 25%–38% and 8%–10% in the corpus callosum and subcortical white matter in the gyri. Cortical gray matter demonstrated relative SNR values closer to unity with a higher percentage of error (35%–40%) in the measurements. Relative SNR values in the phantom decreased by 56% and 62% for the GRAPPA and mSENSE R = 2 methods, respectively, in accordance with theoretical considerations reflecting higher (>1.0) coil g-factors.⁹