PROPELLER for motion-robust imaging of in vivo mouse abdomen at 9.4 T

Irvin Teh, Xavier Golay, David J. Larkman

Research output: Contribution to journalArticle

Abstract

In vivo high-field MRI in the abdomen of small animals is technically challenging because of the small voxel sizes, short T2 and physiological motion. In standard Cartesian sampling, respiratory and gastrointestinal motion can lead to ghosting artefacts. Although respiratory triggering and navigator echoes can either avoid or compensate for motion, they can lead to variable TRs, require invasive intubation and ventilation, or extend TEs. A self-navigated fast spin echo (FSE)-based periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) acquisition was implemented at 9.4 T to enable high-resolution in vivo MRI of mouse abdomen without the use of additional navigators or triggering. T2-weighted FSE-PROPELLER data were compared with single-shot FSE and multi-shot FSE data with and without triggering. Single-shot methods, although rapid and robust to motion, demonstrated strong blurring. Multi-shot FSE data showed better resolution, but suffered from marked blurring in the phase-encoding direction and motion in between shots, leading to ghosting artefacts. When respiratory triggering was used, motion artefacts were largely avoided. However, TRs and acquisition times were lengthened by up to approximately 20%. The PROPELLER data showed a 25% and 61% improvement in signal-to-noise ratio and contrast-to-noise ratio, respectively, compared with multi-shot FSE data, together with a 35% reduction in artefact power. A qualitative comparison between acquisition methods using diffusion-weighted imaging was performed. The results were similar, with the exception that respiratory triggering was unable to exclude major motion artefacts as a result of the sensitisation to motion by the diffusion gradients. The PROPELLER data were of consistently higher quality. Considerations specific to the use of PROPELLER at high field are discussed, including the selection of practical blade widths and the effects on contrast, resolution and artefacts. PROPELLER was implemented and demonstrated as an efficient and motion-robust acquisition strategy in the in-vivo imaging of mouse abdomen at 9.4T. It outperformed single-shot FSE (ssFSE) and multi-shot FSE (msFSE) in terms of SNR, CNR and resistance to artifacts, and circumvented the need for respiratory triggering. Applications in T2-weighted and diffusion-weighted imaging are presented. Here, T2-weighted images of the mouse abdomen were acquired in-vivo and ex-vivo using (I) ssFSE, (II) msFSE, (III) msFSE with respiratory triggering and (IV) FSE-PROPELLER.

Original languageEnglish (US)
Pages (from-to)1077-1086
Number of pages10
JournalNMR in biomedicine
Volume23
Issue number9
DOIs
StatePublished - Nov 1 2010

Keywords

  • 9.4 T
  • Abdomen
  • High field
  • Motion correction
  • Mouse
  • PROPELLER

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Spectroscopy

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