Rapid multislice imaging of hyperpolarized 13C pyruvate and bicarbonate in the heart.
Hyperpolarization of spins via dynamic nuclear polarization (DNP) has been explored as a method to non-invasively study real-time metabolic processes occurring in vivo using (13)C-labeled substrates. Recently, hyperpolarized (13)C pyruvate has been used to characterize in vivo cardiac metabolism in the rat and pig. Conventional 3D spectroscopic imaging methods require in excess of 100 excitations, making it challenging to acquire a full cardiac-gated, breath-held, whole-heart volume. In this article, the development of a rapid multislice cardiac-gated spiral (13)C imaging pulse sequence consisting of a large flip-angle spectral-spatial excitation RF pulse combined with a single-shot spiral k-space trajectory for rapid imaging of cardiac metabolism is described. This sequence permits whole-heart coverage (6 slices, 8.8-mm in-plane resolution) in any plane, allowing imaging of the metabolites of interest, [1-(13)C] pyruvate, [1-(13)C] lactate, and (13)C bicarbonate, within a single breathhold. Pyruvate and bicarbonate cardiac volumes were acquired, while lactate images were not acquired due to low lactate levels in the animal model studied. The sequence was demonstrated with phantom experiments and in vivo testing in a pig model.
Lau
Angus Z
AZ
Department of Medical Biophysics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada. angus.lau@sri.utoronto.ca
Chen
Albert P
AP
Ghugre
Nilesh R
NR
Ramanan
Venkat
V
Lam
Wilfred W
WW
Connelly
Kim A
KA
Wright
Graham A
GA
Cunningham
Charles H
CH
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D006321:Heart / Q000033:anatomy & histology; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009206:Myocardium / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D013552:Swine; D014018:Tissue Distribution
D001639:Bicarbonates; D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D019289:Pyruvic Acid