Abstract
Hyperpolarized [1-(13)C]pyruvate is the leading hyperpolarized injectable contrast agent and is currently under evaluation in clinical trials for molecular imaging of metabolic diseases, including cardiovascular disease and cancer. One aspect limiting broad scalability of the technique is that hyperpolarized (13)C MRI requires specialized (13)C hardware and software that are not generally available on clinical MRI scanners, which employ proton-only detection. Here, we present an approach that uses pulse sequences to transfer (13)C hyperpolarization to methyl protons for detection of the (13)C-(13)C pyruvate singlet, employing proton-only excitation and detection only. The new pulse sequences are robust to the B(1) and B(0) magnetic field inhomogeneities. The work focuses on singlet-to-magnetization (S2M) and rotor-synchronized (R) pulses, both relying on trains of hard pulses with broad spectral width coverage designed to effectively transform hyperpolarized (13)C(2)-singlet hyperpolarization to (1)H polarization on the CH(3) group of [1,2-(13)C(2)]pyruvate. This approach may enable a broader adoption of hyperpolarized MRI as a molecular imaging technique.