Figure 8. Schematic view of the HP method:

The tracer to-be-hyperpolarized is formed by catalytic addition of pH₂ to an unsaturated precursor molecule (a, here: hydroxyethyl-acrylate forms the angiography-tracer²⁷,³⁰ HEP). Next, a pulse sequence is applied subsequently to transfer the spin order (grey bars, here: PH-INEPT+ (ref. ⁴⁵)), and the enhanced ¹³C signal is recorded (c). In b, refocusing pulses are shown in light grey. (c) Real ¹³C-data in the time domain acquired after one HP experiment.