In vivo single-shot 13C spectroscopic imaging of hyperpolarized metabolites by spatiotemporal encoding

• Published in: Journal of magnetic resonance (1997) Vol. 240; pp. 8 - 15
• Main Authors: Schmidt, Rita, Laustsen, Christoffer, Dumez, Jean-Nicolas, Kettunen, Mikko I., Serrao, Eva M., Marco-Rius, Irene, Brindle, Kevin M., Ardenkjaer-Larsen, Jan Henrik, Frydman, Lucio
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2014
• Subjects: Algorithms; Animals; Cancer; Chemical shift imaging; DNP; Echo-Planar Imaging - methods; Hyperpolarized dynamic imaging; Hyperpolarized MRI; Kidney - anatomy & histology; Kidney - pathology; Lactic Acid - metabolism; Lymphoma - pathology; Magnetic Resonance Imaging - methods; Male; Mice; Neoplasms - metabolism; Neoplasms - pathology; Neoplasms, Experimental - pathology; Phantoms, Imaging; Pyruvic Acid - metabolism; Rats; Rats, Sprague-Dawley; Signal-To-Noise Ratio; Spatiotemporal encoding; Spectroscopic imaging; Ultrafast MRI; SPEN; EPSI; Spatiotemporal encoding; Hyperpolarized dynamic imaging; MRI; SAR; DNP; d-DNP; FOV; FT; TE; Hyperpolarized MRI; NMR; RF; PE; Spectroscopic imaging; Ultrafast MRI; CSI; RO; EPI; SR; Chemical shift imaging; Cancer
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2013.12.013

•Novel spectroscopic imaging sequences for hyperpolarized studies are presented.•These sequences use spatiotemporal-encoding and provide 3D MRSI data in ⩽100ms.•Sequences are validated with 13C experiments on phantoms and in vivo. 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 13C 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 [1-13C]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.