Premium
Comparison of parallel acquisition techniques generalized autocalibrating partially parallel acquisitions (GRAPPA) and modified sensitivity encoding (mSENSE) in functional MRI (fMRI) at 3T
Author(s) -
Preibisch Christine,
Wallenhorst Tim,
Heidemann Robin,
Zanella Friedhelm E.,
Lanfermann Heinrich
Publication year - 2008
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21191
Subject(s) - sensitivity (control systems) , computer science , image quality , encoding (memory) , artifact (error) , functional magnetic resonance imaging , signal (programming language) , noise (video) , artificial intelligence , radiology , medicine , image (mathematics) , electronic engineering , engineering , programming language
Purpose To evaluate the parallel acquisition techniques, generalized autocalibrating partially parallel acquisitions (GRAPPA) and modified sensitivity encoding (mSENSE), and determine imaging parameters maximizing sensitivity toward functional activation at 3T. Materials and Methods A total of eight imaging protocols with different parallel imaging techniques (GRAPPA and mSENSE) and reduction factors (R = 1, 2, 3) were compared at different matrix sizes (64 and 128) with respect to temporal noise characteristics, artifact behavior, and sensitivity toward functional activation. Results Echo planar imaging (EPI) with GRAPPA and a reduction factor of 2 revealed similar image quality and sensitivity than full k ‐space EPI. A higher incidence of artifacts and a marked sensitivity loss occurred at R = 3. Even though the same eight‐channel head coil was used for signal detection in all experiments, GRAPPA generally showed more benign patterns of spatially‐varying noise amplification, and mSENSE was also more susceptible to residual unfolding artifacts than GRAPPA. Conclusion At 3T and a reduction factor of 2, parallel imaging can be used with only little penalty with regard to sensitivity. With our implementation and coil setup the performance of GRAPPA was clearly superior to mSENSE. Thus, it seems advisable to pay special attention to the employed parallel imaging method and its implementation. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.