Figure 3

Dynamic 1D slice-selective spectroscopy reveals real-time hyperpolarized [1-¹³C]dehydroascorbate (DHA) to [1-¹³C]vitamin C (VitC) conversion. MR spectra of a normal rat brain is shown in (a), and signal-to-noise ratio quantification of DHA, VitC, and urea phantom (solid line), as well as variable flip angle (VFA) scheme (dash line), are plotted in (b). Hyperpolarized [1-¹³C]VitC signal in a normal rat brain gradually increases over time despite the rapid longitudinal relaxation (in vitro T₁ ~ 29.2 s at 3 Tesla), and hyperpolarized [1-¹³C]DHA signal gradually decreases due to metabolic conversion and longitudinal relaxation (in vitro T₁ ~ 56.5 s at 3 Tesla). Signal corresponding to the [¹³C]urea phantom (placed next to the rat head) also gradually increases, demonstrating the VFA scheme. A sagittal T₂-weighted image demonstrates the imaging slab (green highlighted region).