Second-order motion compensated PRESS for cardiac spectroscopy

Magn Reson Med. 2017 Jan;77(1):57-64. doi: 10.1002/mrm.26099. Epub 2016 Jan 13.

Abstract

Purpose: Second-order motion compensation for point-resolved spectroscopy (PRESS) is proposed to allow for robust single-voxel cardiac spectroscopy throughout the entire cardiac cycle and at various heart rates.

Methods: Bipolar FID spoiling gradient pairs compensating for first and second-order motion were designed and implemented into a cardiac-triggered PRESS sequence on a clinical MR system. A numerical three-dimensional model of cardiac motion was used to optimize and validate the gradient waveforms. In vivo measurements in healthy volunteers were obtained to assess the signal-to-noise ratio (SNR) and triglyceride-to-water ratio (TG/W). SNR gains and variability of TG/W of the proposed approach were evaluated against a conventional PRESS sequence with optimized gradients.

Results: The proposed sequence increases the mean SNR by 32% (W) and 23% (TG) on average with significantly lower variability for different trigger delays. The variability of TG/W quantification over the cardiac cycle is significantly decreased with second-order motion compensated PRESS when compared with conventional PRESS with reduced-spoiler gradients (coefficient of variation: 0.1 ± 0.02 versus 0.37 ± 0.26).

Conclusion: Second-order motion compensated PRESS effectively reduces cardiac motion-induced signal degradation during FID spoiling, providing higher SNR and less variability for TG/W quantification. The sequence is considered promising to assess the TG/W modulation during various interventions including pharmacologically induced stress. Magn Reson Med 77:57-64, 2017. © 2016 Wiley Periodicals, Inc.

Keywords: PRESS; cardiac motion; cardiac spectroscopy; gradient moment nulling; motion compensation; triglyceride.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cardiac Imaging Techniques / methods*
  • Female
  • Heart / diagnostic imaging*
  • Humans
  • Image Processing, Computer-Assisted / methods*
  • Magnetic Resonance Imaging / methods*
  • Movement / physiology
  • Signal-To-Noise Ratio
  • Young Adult