title: Single shot whole brain imaging using spherical stack of spirals trajectories.
abstract: MR-encephalography allows the observation of functional signal in the brain at a frequency of 10 Hz, permitting filtering of physiological "noise" and the detection of single event activations. High temporal resolution is achieved by the use of undersampled non-Cartesian trajectories, parallel imaging and regularized image reconstruction. MR-encephalography is based on 3D-encoding, allowing undersampling in two dimensions and providing advantages in terms of signal to noise ratio. Long readout times, which are necessary for single shot whole brain imaging (up to 75 ms), cause off-resonance artifacts. To meet this issue, a spherical stack of spirals trajectory is proposed in this work. By examining the trajectories in local k-space, it is shown that in areas of strong susceptibility gradients spatial information is fundamentally lost, making a meaningful image reconstruction impossible in the affected areas. It is shown that the loss of spatial information is reduced when using a stack of spirals trajectory compared to concentric shells.
authors: Department of Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106 Freiburg, Germany. jakob.asslaender@uniklinik-freiburg.de
authors: Jakob
authors: J
authors: Assländer
authors: Benjamin
authors: B
authors: Zahneisen
authors: Thimo
authors: T
authors: Hugger
authors: Marco
authors: M
authors: Reisert
authors: Hsu-Lei
authors: HL
authors: Lee
authors: Pierre
authors: P
authors: LeVan
authors: Jürgen
authors: J
authors: Hennig
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D003198:Computer Simulation; D004574:Electromagnetic Fields; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059629:Signal-To-Noise Ratio; D051598:Whole Body Imaging