title: Non-Cartesian parallel imaging reconstruction.
abstract: Non-Cartesian parallel imaging has played an important role in reducing data acquisition time in MRI. The use of non-Cartesian trajectories can enable more efficient coverage of k-space, which can be leveraged to reduce scan times. These trajectories can be undersampled to achieve even faster scan times, but the resulting images may contain aliasing artifacts. Just as Cartesian parallel imaging can be used to reconstruct images from undersampled Cartesian data, non-Cartesian parallel imaging methods can mitigate aliasing artifacts by using additional spatial encoding information in the form of the nonhomogeneous sensitivities of multi-coil phased arrays. This review will begin with an overview of non-Cartesian k-space trajectories and their sampling properties, followed by an in-depth discussion of several selected non-Cartesian parallel imaging algorithms. Three representative non-Cartesian parallel imaging methods will be described, including Conjugate Gradient SENSE (CG SENSE), non-Cartesian generalized autocalibrating partially parallel acquisition (GRAPPA), and Iterative Self-Consistent Parallel Imaging Reconstruction (SPIRiT). After a discussion of these three techniques, several potential promising clinical applications of non-Cartesian parallel imaging will be covered.
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Wright
authors.forename: Jesse I
authors.initials: JI
authors.lastname: Hamilton
authors.forename: Mark A
authors.initials: MA
authors.lastname: Griswold
authors.forename: Vikas
authors.initials: V
authors.lastname: Gulani
authors.forename: Nicole
authors.initials: N
authors.lastname: Seiberlich
mesh_terms: D000465:Algorithms; D016477:Artifacts; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010363:Pattern Recognition, Automated; D012680:Sensitivity and Specificity; D013997:Time Factors
keywords: CG SENSE; SPIRiT; non-Cartesian; non-Cartesian GRAPPA; parallel imaging