Table 2. Comparison of pulse sequences in hyperpolarized ¹³C-MRI.

Sequence	Advantages	Challenges
Fast spectroscopic imaging	Faster by employing multi-echo readouts; still providing continuous spectral coverage; robust for frequency shifts	Limited spectral bandwidth, spatial resolution, and SNR efficiency; relatively slow because of the requirement for phase encoding; susceptible to motion
Model-based imaging	More efficient phase encoding because only relative metabolite chemical shift required	Requires prior knowledge of both metabolite chemical shifts and B0 field map; lower temporal resolution compared to metabolite-specific imaging; susceptible to both motion and frequency shifts
Metabolite-specific imaging	Fastest acquisition method for single metabolite; robust to motion	Requires spectra with sparce and well separated peaks; easy for variable flip angle schemes; susceptible to frequency shifts

SNR = signal-to-noise ratio