title: Monoplanar gradient system for imaging with nonlinear gradients.
abstract: OBJECTIVE
  In this paper we present a monoplanar gradient system capable of imaging a volume comparable with that covered by linear gradient systems. Such a system has been designed and implemented.
  
  
  METHODS
  Building such a system was made possible by relaxing the constraint of global linearity and replacing it with a requirement for local orthogonality. A framework was derived for optimization of local orthogonality within the physical boundaries and geometric constraints. Spatial encoding of magnetic fields was optimized for their local orthogonality over a large field of view.
  
  
  RESULTS
  A coil design consisting of straight wire segments was optimized, implemented, and integrated into a 3T human scanner to show the feasibility of this approach. Initial MR images are shown and further applications of the derived optimization method and the nonlinear planar gradient system are discussed.
  
  
  CONCLUSIONS
  Encoding fields generated by the prototype encoding system were shown to be locally orthogonal and able to encode a cylindrical volume sufficient for some abdomen imaging applications for humans.
authors: Department of Diagnostic Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106, Freiburg, Germany. sebastian.littin@uniklinik-freiburg.de.
authors: Sebastian
authors: S
authors: Littin
authors: CIBM, EPFL, Lausanne, Switzerland.
authors: Daniel
authors: D
authors: Gallichan
authors: Department of Diagnostic Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106, Freiburg, Germany.
authors: Anna Masako
authors: AM
authors: Welz
authors: Department of Diagnostic Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106, Freiburg, Germany.
authors: Feng
authors: F
authors: Jia
authors: Healthcare Sector, Siemens AG, Erlangen, Germany.
authors: Andrew
authors: A
authors: Dewdney
authors: Department of Diagnostic Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106, Freiburg, Germany.
authors: Hans
authors: H
authors: Weber
authors: Department of Diagnostic Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106, Freiburg, Germany.
authors: Gerrit
authors: G
authors: Schultz
authors: Department of Diagnostic Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106, Freiburg, Germany.
authors: Jürgen
authors: J
authors: Hennig
authors: Department of Diagnostic Radiology, Medical Physics, University Medical Center Freiburg, Breisacher Str. 60a, 79106, Freiburg, Germany.
authors: Maxim
authors: M
authors: Zaitsev
mesh_terms: D000465:Algorithms; D016477:Artifacts; D044962:Data Compression / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D017711:Nonlinear Dynamics; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation
keywords: Gradients; Image reconstruction; Magnetic resonance imaging (MRI); Nonlinear encoding fields; PatLoc; Planar gradient; Spatial encoding