PURPOSE A ghost correction strategy for Simultaneous Multi-Slice (SMS) EPI methods that provides improved ghosting artifact reduction compared to conventional methods is presented. Conventional Nyquist ghost correction methods for SMS-EPI rely on navigator data that contain phase errors from all slices in the simultaneously acquired slice-group. These navigator data may contain spatially nonlin...

The Geophysical High Order Suite for Turbulence (GHOST) is a highly scalable Fortran 90-95 pseudo–spectral code that solves a variety of PDEs that are often encountered in turbulence studies. The use of pseudo–spectral methods has a long and distinguished history in the turbulence community that hardly needs expounding upon. The numerics employ a GalerkinFourier spectral method and nonlinear te...

2. The Carlitz-Witt suite 5 2.1. The classical ghost-Witt equivalence theorem . . . . . . . . . . . . . 5 2.2. Classical Witt vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3. The Carlitz ghost-Witt equivalence theorem . . . . . . . . . . . . . . 9 2.4. Carlitz-Witt vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.5. F -modules . . . . . . . . . . . . . . ...

Ghost artifacts in echoplanar imaging (EPI) arise from phase errors caused by differences in eddy currents and gradient ramping during left-to-right traversal of kx(forward echo) versus right-to-left traversal of kx (reverse echo). Reference scans do not always reduce the artifact and may make image quality worse. To eliminate the need for reference scans, a ghost artifact reduction technique b...

Biologists routinely compare inferences about the order of evolutionary branching (phylogeny) with the order in which groups appear in the fossil record (stratigraphy). Where they conflict, ghost ranges are inferred: intervals of geological time where a fossil lineage should exist, but for which there is no direct evidence. The presence of very numerous and/or extensive ghost ranges is often be...