Double spin-echo sequence for rapid spectroscopic imaging of hyperpolarized 13C

J Magn Reson. 2007 Aug;187(2):357-62. doi: 10.1016/j.jmr.2007.05.014. Epub 2007 Jun 2.

Abstract

Dynamic nuclear polarization of metabolically active compounds labeled with (13)C has been introduced as a means for imaging metabolic processes in vivo. To differentiate between the injected compound and the various metabolic products, an imaging technique capable of separating the different chemical-shift species must be used. In this paper, the design and testing of a pulse sequence for rapid magnetic resonance spectroscopic imaging (MRSI) of hyperpolarized (13)C is presented. The pulse sequence consists of a small-tip excitation followed by a double spin echo using adiabatic refocusing pulses and a "flyback" echo-planar readout gradient. Key elements of the sequence are insensitivity to calibration of the transmit gain, the formation of a spin echo giving high-quality spectral information, and a small effective tip angle that preserves the magnetization for a sufficient duration. Experiments in vivo showed three-dimensional coverage with excellent spectral quality and SNR.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Calibration
  • Carbon Isotopes
  • Magnetic Resonance Spectroscopy / methods*
  • Phantoms, Imaging
  • Pyruvic Acid / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Reproducibility of Results
  • Sensitivity and Specificity

Substances

  • Carbon Isotopes
  • Pyruvic Acid