Partially parallel imaging with localized sensitivities (PILS)

  title={Partially parallel imaging with localized sensitivities (PILS)},
  author={Mark A. Griswold and Peter M. Jakob and Mathias Nittka and James W. Goldfarb and Axel Haase},
  journal={Magnetic Resonance in Medicine},
In this study a novel partially parallel acquisition method is presented, which can be used to accelerate image acquisition using an RF coil array for spatial encoding. In this technique, Parallel Imaging with Localized Sensitivities (PILS), it is assumed that the individual coils in the array have localized sensitivity patterns, in that their sensitivity is restricted to a finite region of space. Within the PILS model, a detailed, highly accurate RF field map is not needed prior to… 

Generalized autocalibrating partially parallel acquisitions (GRAPPA)

This technique, GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) is an extension of both the PILS and VD‐AUTO‐SMASH reconstruction techniques and provides unaliased images from each component coil prior to image combination.

Variable-Density Parallel Imaging With Partially Localized Coil Sensitivities

A novel, fast variable-density parallel imaging method is presented, which reconstructs different field-of-views from separate frequencies according to the local sampling density in k-space, which can produce high SNR-efficiency images without the need for accurate estimation of coil sensitivities.

Image reconstructions with the rotating RF coil.

Simulation‐based investigation of partially parallel imaging with a linear array at high accelerations

Simulations have been conducted to evaluate the impact of slice depth and noise on partially parallel reconstructions for the case of a square linear array of overlapped elements that are parallel to the imaging plane, and indicate that even when sensitivity distributions are exactly known, the linear surface array can only provide high accelerations over a limited imaging depth.

Parallel magnetic resonance imaging using coils with localized sensitivities.

Overcoming phase effects of voxel-sized coils in planar and cylindrical arrays

  • M. McDougallS. Wright
  • Physics
    The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
  • 2004
The signal-phase interactions of planar and cylindrical arrays of voxel-sized coils are discussed and methods for phase manipulation for optimization are suggested.

Recent advances in image reconstruction, coil sensitivity calibration, and coil array design for SMASH and generalized parallel MRI

A generalized formalism is described which may be used to understand the relations between SMASH and SENSE, to derive typical implementations of each as special cases, and to form hybrid techniques combining some of the advantages of both.

Field‐of‐view limitations in parallel imaging

It is demonstrated that SENSE fails to reconstruct correct images when coil sensitivity maps are used that do not automatically account for the object size and therefore the aliasing in the reconstructed images, however, with the use of aliased high‐resolution Coil sensitivity maps, accurate SENSE reconstructions can be generated.

Autocalibrated coil sensitivity estimation for parallel imaging

Some of the advanced methods to obtain coil sensitivity‐related information, focusing particularly on the class of methods referred to as autocalibrating, are covered.



SENSE: Sensitivity encoding for fast MRI

The problem of image reconstruction from sensitivity encoded data is formulated in a general fashion and solved for arbitrary coil configurations and k‐space sampling patterns and special attention is given to the currently most practical case, namely, sampling a common Cartesian grid with reduced density.

Imaging time reduction through multiple receiver coil data acquisition and image reconstruction

This technique enables the collection of data necessary for image reconstruction in a reduced number of phase‐encoded acquisitions, which results in a 50% reduction in minimum scan time and may be useful in time‐critical procedures.

Fast imaging using subencoding data sets from multiple detectors

  • J. RaC. Rim
  • Physics, Geology
    Magnetic resonance in medicine
  • 1993
A new fast imaging method using a subencoding data acquisition scheme and a multiple coil receiver system is proposed and demonstrated, which can be easily adapted to conventional imaging methods including fast imaging to further reduce the scan time.

The NMR phased array

We describe methods for simultaneously acquiring and subsequently combining data from a multitude of closely positioned NMR receiving coils. The approach is conceptually similar to phased array radar

Accelerated cardiac imaging using the SMASH technique.

The increased imaging speed provided by SMASH was used to obtain images with reduced breathhold duration, enhanced spatial resolution, and increased temporal resolution in healthy volunteers.

Signal‐to‐noise ratio and signal‐to‐noise efficiency in SMASH imaging

A general theory of signal‐to‐noise ratio (SNR) in simultaneous acquisition of spatial harmonics (SMASH) imaging is presented, and the predictions of the theory are verified in imaging experiments

Simultaneous acquisition of spatial harmonics (SMASH): Fast imaging with radiofrequency coil arrays

A twofold savings in image acquisition time is demonstrated here using commercial phased array coils on two different MR‐imaging systems, and larger time savings factors can be expected for appropriate coil designs.

An algorithm for rapid image acquisition using multiple receiver coils

    Transceive phased array designed for imaging at 3.0T

    • Proceedings of the 6th Annual Meeting of ISMRM, Sydney, Australia,
    • 1998

    An RF coil array designed specifically for cardiac SMASH imaging

    • Proceedings of the 6th Annual Meeting of ISMRM, Sydney, Australia,
    • 1998