Phase-constrained parallel MR image reconstruction

Jacob D. Willig-Onwuachi, Ernest N. Yeh, Aaron K. Grant, Michael A. Ohliger, Charles A. McKenzie, Daniel K. Sodickson

Research output: Contribution to journalArticlepeer-review


A generalized method for phase-constrained parallel MR image reconstruction is presented that combines and extends the concepts of partial-Fourier reconstruction and parallel imaging. It provides a framework for reconstructing images employing either or both techniques and for comparing image quality achieved by varying k-space sampling schemes. The method can be used as a parallel image reconstruction with a partial-Fourier reconstruction built in. It can also be used with trajectories not readily handled by straightforward combinations of partial-Fourier and SENSE-like parallel reconstructions, including variable-density, and non-Cartesian trajectories. The phase constraint specifies a better-conditioned inverse problem compared to unconstrained parallel MR reconstruction alone. This phase-constrained parallel MRI reconstruction offers a one-step alternative to the standard combination of homodyne and SENSE reconstructions with the added benefit of flexibility of sampling trajectory. The theory of the phase-constrained approach is outlined, and its calibration requirements and limitations are discussed. Simulations, phantom experiments, and in vivo experiments are presented.

Original languageEnglish (US)
Pages (from-to)187-198
Number of pages12
JournalJournal of Magnetic Resonance
Issue number2
StatePublished - Oct 2005


  • Coil arrays
  • Constrained reconstruction
  • Parallel imaging
  • Partial-Fourier

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Nuclear and High Energy Physics
  • Condensed Matter Physics


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