Optimized radiofrequency coil setup for MR examination of living isolated rat hearts in a horizontal 9.4T magnet

Magn Reson Med. 2015 Jun;73(6):2398-405. doi: 10.1002/mrm.25369. Epub 2014 Jul 12.

Abstract

Purpose: (i) To optimize an MR-compatible organ perfusion setup for the nondestructive investigation of isolated rat hearts by placing the radiofrequency (RF) coil inside the perfusion chamber; (ii) to characterize the benefit of this system for diffusion tensor imaging and proton ((1) H-) MR spectroscopy.

Methods: Coil quality assessment was conducted both on the bench, and in the magnet. The benefit of the new RF-coil was quantified by measuring signal-to-noise ratio (SNR), accuracy, and precision of diffusion tensor imaging/error in metabolite amplitude estimation, and compared to an RF-coil placed externally to the perfusion chamber.

Results: The new design provided a 59% gain in signal-to-noise ratio on a fixed rat heart compared to using an external resonator, which found reflection in an improvement of living heart data quality, compared to previous external resonator studies. This resulted in 14-29% improvement in accuracy and precision of diffusion tensor imaging. The Cramer-Rao lower bounds for metabolite amplitude estimations were up to 5-fold smaller.

Conclusion: Optimization of MR-compatible perfusion equipment advances the study of rat hearts with improved signal-to-noise ratio performance, and thus improved accuracy/precision.

Keywords: Langendorff perfusion; cardiac magnetic resonance imaging; diffusion tensor imaging; proton spectroscopy; radiofrequency coil.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Equipment Design
  • Heart / anatomy & histology*
  • Image Enhancement / instrumentation*
  • Magnetic Resonance Imaging / instrumentation*
  • Rats
  • Rats, Sprague-Dawley
  • Signal-To-Noise Ratio