A fast chemical exchange saturation transfer imaging scheme based on single-shot spatiotemporal encoding

Magn Reson Med. 2017 May;77(5):1786-1796. doi: 10.1002/mrm.26258. Epub 2016 Apr 27.

Abstract

Purpose: To design a new approach that can not only keep the spatial and temporal resolution but also have better built-in immunity to magnetic field inhomogeneity and chemical shift effects than the single-shot echo planar imaging (EPI) for chemical exchange saturation transfer (CEST) MRI.

Method: The single-shot spatiotemporally encoded (SPEN) MRI sequence was combined with a continuous wave saturation pulse for fast CEST MRI (CEST-SPEN MRI). The resulting images were super-resolved reconstructed by a hybrid method that solves the l1 norm minimization together with total variation (TV) regularization. Partial Lorentzian fitting was used to analyze the subsequent Z-spectra.

Results: Experimental results of a creatine phantom and in vivo tumor rat brains show that CEST-SPEN MRI has good capability in providing CEST-based and NOE-based contrast images.

Conclusions: Compared with CEST-EPI, CEST-SPEN MRI has better immunity to magnetic field inhomogeneity and provides better contrast images within identical acquisition time, especially under an identical inhomogeneous field. Magn Reson Med 77:1786-1796, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Keywords: chemical exchange saturation transfer; inhomogeneous field; magnetic resonance imaging; nuclear Overhauser enhancement; spatiotemporal encoding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Animals
  • Artifacts
  • Brain / diagnostic imaging*
  • Contrast Media / chemistry
  • Echo-Planar Imaging / methods*
  • Image Processing, Computer-Assisted / methods
  • Magnetic Fields
  • Magnetic Resonance Imaging / methods*
  • Phantoms, Imaging
  • Rats
  • Signal-To-Noise Ratio
  • Time Factors

Substances

  • Contrast Media