Abstract
Hyperpolarization is the general term for a method of enhancing the spin-polarization difference of populations of nuclei in a magnetic field. No less than 5 distinct techniques (dynamic nuclear polarization [DNP]; parahydrogen-induced polarization-parahydrogen and synthesis allow dramatically enhanced nuclear alignment [PHIP-PASADENA]; xenon/helium polarization transfer; Brute Force; (1)H hyperpolarized water) are currently under exhaustive investigation as means of amplifying the intrinsically (a few parts per million) weak signal intensity used in conventional MR neuroimaging and spectroscopy. HD-MR imaging in vivo is a metabolic imaging tool causing much of the interest in HD-MR imaging. The most successful to date has been DNP, in which carbon-13 ((13)C) pyruvic acid has shown many. PHIP-PASADENA with (13)C succinate has shown HD-MR metabolism in vivo in tumor-bearing mice of several types, entering the Krebs-tricarboxylic acid cycle for ultrafast detection with (13)C MR imaging, MR spectroscopy, and chemical shift imaging. We will discuss 5 promising preclinical studies: (13)C succinate PHIP in brain tumor; (13)C ethylpyruvate DNP and (13)C acetate; DNP in rodent brain; (13)C succinate PHIP versus gadolinium imaging of stroke; and (1)H hyperpolarized imaging. Recent developments in clinical (13)C neurospectroscopy encourage us to overcome the remaining barriers to clinical HD-MR imaging.
Highlights
Recent technical advances have liberated the spectroscopist, previously confined to performing 13C MR spectroscopy with proton decoupling in the posterior brain, to imaging frontal brain regions believed to be responsible for most cognitive functions
In examining a representative extracerebral tumor renal cancer (RENCA) cell, believed to express succinate dehydrogenase oncogene, almost the entire Krebs-TCA cycle was successfully imaged by using the parahydrogen-induced polarization (PHIP) reagent hyperpolarized 1-13C succinate (Fig 13), while another tumor, lymphoma A-20 expressing hypoxia-induced factor (HIF)-1␣, albeit at a much lower titer than that of glioblastoma, metabolized 1-13C succinate through the TCA cycle only as far as malate.[25]
PHIP may offer an early and specific diagnosis for tumor and for stroke, based on unique 13C metabolic profiles obtained in seconds
Summary
Spatial Contrast Chemical shift imaging, so-called because multiple spectra are acquired during a single MR spectroscopy examination, provides a regionally specific diagnosis of brain tumor, based on a 20% increase or more in biomarkers choline/Cr and myoinositol/Cr ratios.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
