Dotarem gd chelate

28.5 mg [1-¹³C]pyruvic acid (Cambridge Isotope Laboratories) were polarized to ~30% at 1.42 K and 94 GHz with a HyperSense DNP system (Oxford Instruments). Before insertion into the DNP system, the neat pyruvic acid was mixed with 1.7% by weight OX063 trityl radical (Oxford Instruments) and Dotarem^™ Gd chelate (Guerbet) was added to achieve a total concentration of 15 mmol per mole pyruvate. 4 mL Tris-buffered saline was heated to 190°C at 10 bar, and was used to rapidly dissolve the frozen sample. This solution was diluted using sufficient oxygenated Krebs-Henseleit buffer, as above but without BSA, to yield the desired hyperpolarized pyruvate concentration. The solution was mixed thoroughly and injected using syringe pump in lieu of the steady-state perfusate until the hyperpolarized solution was gone (32 mM) or until 20 ml had been injected (all other hyperpolarized pyruvate concentrations). Note that the dilution buffer was prepared with additional lactate such that when mixed with the hyperpolarized solution the resulting injectate maintained the same lactate concentration as the steady-state perfusion buffer.

28.5 mg [1-¹³C]pyruvic acid (Cambridge Isotope Laboratories) mixed with 15 mM OX063 trityl radical (Oxford Instruments) and 1.5 mM Dotarem Gd chelate (Guerbet) was polarized to ~30% at 1.42 K and 94 GHz with a HyperSense DNP system (Oxford Instruments). 4 mL of buffer, containing 50mM Tris, 80mM NaOH, and 100 mg/L EDTA, was heated to 190°C at 10 bar, and was used to rapidly dissolve the frozen sample. This sample was further diluted in 6.0 mL oxygenated Krebs-Henseleit buffer (without BSA, which was found to cause unacceptable signal loss during sample transport), yielding a neutral, isotonic solution of 32 mM [1-¹³C] pyruvate. This solution was injected into the perfusate line at 10 mL/min in lieu of the steady-state perfusion buffer. After the 60 seconds required to inject the hyperpolarized solution, lung perfusion was restored.