Separation of parallel encoded complex-valued slices (SPECS) from a single complex-valued aliased coil image. Magn Reson Imaging 2016 Apr;34(3):359-69
Date
11/28/2015Pubmed ID
26612076Pubmed Central ID
PMC4761326DOI
10.1016/j.mri.2015.11.003Scopus ID
2-s2.0-84957937705 (requires institutional sign-in at Scopus site) 2 CitationsAbstract
PURPOSE: Achieving a reduction in scan time with minimal inter-slice signal leakage is one of the significant obstacles in parallel MR imaging. In fMRI, multiband-imaging techniques accelerate data acquisition by simultaneously magnetizing the spatial frequency spectrum of multiple slices. The SPECS model eliminates the consequential inter-slice signal leakage from the slice unaliasing, while maintaining an optimal reduction in scan time and activation statistics in fMRI studies.
MATERIALS AND METHODS: When the combined k-space array is inverse Fourier reconstructed, the resulting aliased image is separated into the un-aliased slices through a least squares estimator. Without the additional spatial information from a phased array of receiver coils, slice separation in SPECS is accomplished with acquired aliased images in shifted FOV aliasing pattern, and a bootstrapping approach of incorporating reference calibration images in an orthogonal Hadamard pattern.
RESULT: The aliased slices are effectively separated with minimal expense to the spatial and temporal resolution. Functional activation is observed in the motor cortex, as the number of aliased slices is increased, in a bilateral finger tapping fMRI experiment.
CONCLUSION: The SPECS model incorporates calibration reference images together with coefficients of orthogonal polynomials into an un-aliasing estimator to achieve separated images, with virtually no residual artifacts and functional activation detection in separated images.
Author List
Rowe DB, Bruce IP, Nencka AS, Hyde JS, Kociuba MCAuthor
Andrew S. Nencka PhD Director, Associate Professor in the Radiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AlgorithmsArtifacts
Brain
Brain Mapping
Calibration
Computer Simulation
Echo-Planar Imaging
Fourier Analysis
Humans
Image Enhancement
Image Interpretation, Computer-Assisted
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Phantoms, Imaging
