Compressed sensing for resolution enhancement of hyperpolarized 13C flyback 3D-MRSI.
High polarization of nuclear spins in liquid state through dynamic nuclear polarization has enabled the direct monitoring of 13C metabolites in vivo at very high signal-to-noise, allowing for rapid assessment of tissue metabolism. The abundant SNR afforded by this hyperpolarization technique makes high-resolution 13C 3D-MRSI feasible. However, the number of phase encodes that can be fit into the short acquisition time for hyperpolarized imaging limits spatial coverage and resolution. To take advantage of the high SNR available from hyperpolarization, we have applied compressed sensing to achieve a factor of 2 enhancement in spatial resolution without increasing acquisition time or decreasing coverage. In this paper, the design and testing of compressed sensing suited for a flyback 13C 3D-MRSI sequence are presented. The key to this design was the undersampling of spectral k-space using a novel blipped scheme, thus taking advantage of the considerable sparsity in typical hyperpolarized 13C spectra. Phantom tests validated the accuracy of the compressed sensing approach and initial mouse experiments demonstrated in vivo feasibility.
Hu
Simon
S
Department of Radiology, University of California, Box 2512, 1700 4th Street, QB3 building, Suite 102, San Francisco, CA 94158-2512, USA.
Lustig
Michael
M
Chen
Albert P
AP
Crane
Jason
J
Kerr
Adam
A
Kelley
Douglas A C
DA
Hurd
Ralph
R
Kurhanewicz
John
J
Nelson
Sarah J
SJ
Pauly
John M
JM
Vigneron
Daniel B
DB
D000818:Animals; D002247:Carbon Isotopes; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D051379:Mice; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000378:metabolism*; D012815:Signal Processing, Computer-Assisted
D002247:Carbon Isotopes