In vivo single-shot 13C spectroscopic imaging of hyperpolarized metabolites by spatiotemporal encoding.
Hyperpolarized metabolic imaging is a growing field that has provided a new tool for analyzing metabolism, particularly in cancer. Given the short life times of the hyperpolarized signal, fast and effective spectroscopic imaging methods compatible with dynamic metabolic characterizations are necessary. Several approaches have been customized for hyperpolarized (13)C MRI, including CSI with a center-out k-space encoding, EPSI, and spectrally selective pulses in combination with spiral EPI acquisitions. Recent studies have described the potential of single-shot alternatives based on spatiotemporal encoding (SPEN) principles, to derive chemical-shift images within a sub-second period. By contrast to EPSI, SPEN does not require oscillating acquisition gradients to deliver chemical-shift information: its signal encodes both spatial as well as chemical shift information, at no extra cost in experimental complexity. SPEN MRI sequences with slice-selection and arbitrary excitation pulses can also be devised, endowing SPEN with the potential to deliver single-shot multi-slice chemical shift images, with a temporal resolution required for hyperpolarized dynamic metabolic imaging. The present work demonstrates this with initial in vivo results obtained from SPEN-based imaging of pyruvate and its metabolic products, after injection of hyperpolarized [1-(13)C]pyruvate. Multi-slice chemical-shift images of healthy rats were obtained at 4.7T in the region of the kidney, and 4D (2D spatial, 1D spectral, 1D temporal) data sets were obtained at 7T from a murine lymphoma tumor model.
Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
Rita
R
Schmidt
MR Research Centre, Aarhus University, Denmark; Danish Research Centre for Magnetic Resonance, Hvidovre Hospital, Denmark.
Christoffer
C
Laustsen
Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
Jean-Nicolas
JN
Dumez
Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, United Kingdom.
Mikko I
MI
Kettunen
Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, United Kingdom.
Eva M
EM
Serrao
Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, United Kingdom.
Irene
I
Marco-Rius
Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, United Kingdom.
Kevin M
KM
Brindle
Danish Research Centre for Magnetic Resonance, Hvidovre Hospital, Denmark; GE Healthcare, Broendby, Denmark.
Jan Henrik
JH
Ardenkjaer-Larsen
Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel. Electronic address: lucio.frydman@weizmann.ac.il.
Lucio
L
Frydman
D000465:Algorithms; D000818:Animals; D017352:Echo-Planar Imaging / Q000379:methods; D007668:Kidney / Q000033:anatomy & histology / Q000473:pathology; D019344:Lactic Acid / Q000378:metabolism; D008223:Lymphoma / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology*; D009374:Neoplasms, Experimental / Q000473:pathology; D019047:Phantoms, Imaging; D019289:Pyruvic Acid / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D059629:Signal-To-Noise Ratio
D019344:Lactic Acid; D019289:Pyruvic Acid
Cancer; Chemical shift imaging; DNP; Hyperpolarized MRI; Hyperpolarized dynamic imaging; Spatiotemporal encoding; Spectroscopic imaging; Ultrafast MRI