ANTHEM: anatomically tailored hexagonal MRI

Manojkumar Saranathan, Venkat Ramanan, Rakesh Gulati, Ramesh Venkatesan

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Purpose: This study aimed to investigate the use of anatomically tailored hexagonal sampling for scan-time and error reduction in MRI. Materials and Methods: Anatomically tailored hexagonal MRI (ANTHEM), a method that combines hexagonal sampling with specific symmetry in anatomical geometry, is proposed. By using hexagonal sampling, aliasing artifacts are moved to regions where, due to the nature of the anatomy, aliasing is inconsequential. This can be used to either reduce scan time while maintaining spatial resolution or reduce residual errors in speedup techniques like UNFOLD and k-t BLAST/SENSE, which undersample k-space and unwrap fold-over artifacts during reconstruction. Computer simulations as well as phantom and volunteer studies were used to validate the theory. A simplified reconstruction algorithm for hexagonally sampled and subsampled k-space data was also used. Results: A reduction in sampling density of 13.4% and 25% in each hexagonally sampled dimension was achieved for spherical and conical geometries without aliasing or reduction in spatial resolution. Optimal subsampling schemes that can be utilized by UNFOLD and k-t BLAST/SENSE were derived using hexagonal subsampling, which resulted in maximal, isotropic dispersal of the aliases. In combination with UNFOLD, ANTHEM was shown to move residual aliasing artifacts to the corners of the field of view, yielding reduced artifacts in CINE reconstructions. Conclusions: ANTHEM was successful in reducing acquisition time in conventional MRI and in reducing errors in UNFOLD imaging.

Original languageEnglish (US)
Pages (from-to)1039-1047
Number of pages9
JournalMagnetic Resonance Imaging
Volume25
Issue number7
DOIs
StatePublished - Sep 2007
Externally publishedYes

Keywords

  • Hexagonal sampling
  • Rapid imaging
  • Spatiotemporal sampling
  • UNFOLD

ASJC Scopus subject areas

  • Biophysics
  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging

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