High Resolution $^{13}$C MRI With Hyperpolarized Urea: In Vivo $T_{2}$ Mapping and $^{15}$N 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 (IEEE Trans. Medical Imaging, 2014)