High resolution 13C MRI with hyperpolarized urea: In vivo T 2 mapping and 15N labeling effects

Galen D. Reed, Cornelius Von Morze, Robert Bok, Bertram L. Koelsch, Mark Van Criekinge, Kenneth J. Smith, Hong Shang, Peder E.Z. Larson, John Kurhanewicz, Daniel B. Vigneron

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13C steady state free precession (SSFP) magnetic resonance imaging and effective spin-spin relaxation time (T2) mapping were performed using hyperpolarized [13C] urea and [13C, 15N2] urea injected intravenously in rats. 15N labeling gave large T2 increases both in solution and in vivo due to the elimination of a strong scalar relaxation pathway. The T2 increase was pronounced in the kidney, with [13C,15N 2] urea giving T2 values of 6.3±1.3s in the cortex and medulla, and 11±2s in the renal pelvis. The measured T2 in the aorta was 1.3±0.3s. [13C] urea showed shortened T 2 values in the kidney of 0.23±0.03s compared to 0.28±0.03s measured in the aorta. The enhanced T2 of [ 13C,15N2] urea was utilized to generate large signal enhancement by SSFP acquisitions with flip angles approaching the fully refocused regime. Projection images at 0.94 mm in-plane resolution were acquired with both urea isotopes, with [13C,15N2] urea giving a greater than four-fold increase in signal-to-noise ratio over [ 13C] urea.

Original languageEnglish
Article number6648454
Pages (from-to)362-371
Number of pages10
JournalIEEE Transactions on Medical Imaging
Issue number2
StatePublished - Feb 2014


  • Angiography
  • Dynamic nuclear polarization
  • Hyperpolarized
  • Steady state free precession (SSFP)
  • Urea


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