title: Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents.
abstract: Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due to fundamental constraints imposed by the hyperpolarized state, exotic imaging and reconstruction techniques are commonly used. A practical system for characterization of dynamic, multi-spectral imaging methods is critically needed. Such a system must reproducibly recapitulate the relevant chemical dynamics of normal and pathological tissues. The most widely utilized substrate to date is hyperpolarized [1-(13)C]-pyruvate for assessment of cancer metabolism. We describe an enzyme-based phantom system that mediates the conversion of pyruvate to lactate. The reaction is initiated by injection of the hyperpolarized agent into multiple chambers within the phantom, each of which contains varying concentrations of reagents that control the reaction rate. Multiple compartments are necessary to ensure that imaging sequences faithfully capture the spatial and metabolic heterogeneity of tissue. This system will aid the development and validation of advanced imaging strategies by providing chemical dynamics that are not available from conventional phantoms, as well as control and reproducibility that is not possible in vivo.
authors.affiliation: Imaging Physics, University of Texas M.D. Anderson Cancer Center.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Walker
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center.
authors.forename: Matthew
authors.initials: M
authors.lastname: Merritt
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center.
authors.forename: Jian-Xiong
authors.initials: JX
authors.lastname: Wang
authors.affiliation: Imaging Physics, University of Texas M.D. Anderson Cancer Center; jbankson@mdanderson.org.
authors.forename: James A
authors.initials: JA
authors.lastname: Bankson
mesh_terms: D002247:Carbon Isotopes; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D019047:Phantoms, Imaging; D019289:Pyruvic Acid / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D002247:Carbon Isotopes; D019344:Lactic Acid; D019289:Pyruvic Acid