Selective spectroscopic imaging of hyperpolarized pyruvate and its metabolites using a single-echo variable phase advance method in balanced SSFP.
In balanced steady state free precession (bSSFP), the signal intensity has a well-known dependence on the off-resonance frequency, or, equivalently, the phase advance between successive radiofrequency (RF) pulses. The signal profile can be used to resolve the contributions from the spectrally separated metabolites. This work describes a method based on use of a variable RF phase advance to acquire spatial and spectral data in a time-efficient manner for hyperpolarized 13C MRI.



The technique relies on the frequency response from a bSSFP acquisition to acquire relatively rapid, high-resolution images that may be reconstructed to separate contributions from different metabolites. The ability to produce images from spectrally separated metabolites was demonstrated in vitro, as well as in vivo following administration of hyperpolarized 1-13C pyruvate in mice with xenograft tumors.



In vivo images of pyruvate, alanine, pyruvate hydrate, and lactate were reconstructed from four images acquired in 2 s with an in-plane resolution of 1.25 × 1.25 mm(2) and 5 mm slice thickness.



The phase advance method allowed acquisition of spectroscopically selective images with high spatial and temporal resolution. This method provides an alternative approach to hyperpolarized 13C spectroscopic MRI that can be combined with other techniques such as multiecho or fluctuating equilibrium bSSFP. Magn Reson Med 76:1102-1115, 2016. © 2015 Wiley Periodicals, Inc.
Division of MR Research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA. gvarma@bidmc.harvard.edu.
Gopal
G
Varma
Division of MR Research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Xiaoen
X
Wang
Advanced Imaging Research Center, Radiology, UT Southwestern Medical Center, Dallas, Texas, USA.
Elena
E
Vinogradov
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Rupal S
RS
Bhatt
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Vikas P
VP
Sukhatme
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Pankaj
P
Seth
Advanced Imaging Research Center, Radiology, UT Southwestern Medical Center, Dallas, Texas, USA.
Robert E
RE
Lenkinski
Division of MR Research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
David C
DC
Alsop
Division of MR Research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Aaron K
AK
Grant
D000072283:A549 Cells; D000409:Alanine / Q000378:metabolism*; D000465:Algorithms; D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism; D002247:Carbon Isotopes / Q000493:pharmacokinetics; D066241:Carbon-13 Magnetic Resonance Spectroscopy / Q000379:methods*; D045744:Cell Line, Tumor; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D019344:Lactic Acid / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D057054:Molecular Imaging / Q000379:methods; D009374:Neoplasms, Experimental / Q000378:metabolism* / Q000473:pathology; D019289:Pyruvic Acid / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
D014408:Biomarkers, Tumor; D002247:Carbon Isotopes; D019344:Lactic Acid; D019289:Pyruvic Acid; D000409:Alanine
bSSFP; hyperpolarized 13C; phase advance; pyruvate