Quantification of vitamin C in the rat brain in vivo using short echo-time 1H MRS.
Both ultrashort echo-time STEAM and MEGA-PRESS-edited spectroscopy were used to validate noninvasive quantification of vitamin C (ascorbate) in the developing rat brain, where changes in ascorbate concentration have been reported. Despite strong overlap with resonances from glutamine, glutamate, glutathione, and macromolecules, reliable quantification of ascorbate (Cramer-Rao lower bounds<0.2 micromol/g) by LCModel analysis of STEAM (TE=2 ms) spectra was possible at 9.4 T. Ascorbate concentrations quantified from the STEAM spectra were in very good agreement with concentrations calculated from fully resolved ascorbate resonances in MEGA-PRESS-edited spectra measured from identical volumes of interest. Ascorbate concentrations measured using STEAM decreased with increasing postnatal rat age, in agreement with published brain ascorbate concentrations measured in vitro using high-performance liquid chromatography (HPLC).
Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota 55455, USA. melissa@cmrr.umn.edu
Melissa
M
Terpstra
Ivan
I
Tkác
Raghavendra
R
Rao
Rolf
R
Gruetter
D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001205:Ascorbic Acid / Q000032:analysis*; D001921:Brain / Q000378:metabolism*; D005240:Feasibility Studies; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011522:Protons; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
D011522:Protons; D001205:Ascorbic Acid