title: T(2) relaxation times of (13)C metabolites in a rat hepatocellular carcinoma model measured in vivo using (13)C-MRS of hyperpolarized [1-(13)C]pyruvate.
abstract: A single-voxel Carr-Purcell-Meibloom-Gill sequence was developed to measure localized T(2) relaxation times of (13)C-labeled metabolites in vivo for the first time. Following hyperpolarized [1-(13)C]pyruvate injections, pyruvate and its metabolic products, alanine and lactate, were observed in the liver of five rats with hepatocellular carcinoma and five healthy control rats. The T(2) relaxation times of alanine and lactate were both significantly longer in HCC tumors than in normal livers (p < 0.002). The HCC tumors also showed significantly higher alanine signal relative to the total (13)C signal than normal livers (p < 0.006). The intra- and inter-subject variations of the alanine T(2) relaxation time were 11% and 13%, respectively. The intra- and inter-subject variations of the lactate T(2) relaxation time were 6% and 7%, respectively. The intra-subject variability of alanine to total carbon ratio was 16% and the inter-subject variability 28%. The intra-subject variability of lactate to total carbon ratio was 14% and the inter-subject variability 20%. The study results show that the signal level and relaxivity of [1-(13)C]alanine may be promising biomarkers for HCC tumors. Its diagnostic values in HCC staging and treatment monitoring are yet to be explored.
authors.affiliation: Global Applied Science Laboratory, GE Healthcare, CA, USA. yi-fen.yen@ge.com
authors.forename: Yi-Fen
authors.initials: YF
authors.lastname: Yen
authors.forename: Patrick
authors.initials: P
authors.lastname: Le Roux
authors.forename: Dirk
authors.initials: D
authors.lastname: Mayer
authors.forename: Randy
authors.initials: R
authors.lastname: King
authors.forename: Daniel
authors.initials: D
authors.lastname: Spielman
authors.forename: James
authors.initials: J
authors.lastname: Tropp
authors.forename: Kim
authors.initials: K
authors.lastname: Butts Pauly
authors.forename: Adolf
authors.initials: A
authors.lastname: Pfefferbaum
authors.forename: Shreyas
authors.initials: S
authors.lastname: Vasanawala
authors.forename: Ralph
authors.initials: R
authors.lastname: Hurd
mesh_terms: D000409:Alanine / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002247:Carbon Isotopes / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D019289:Pyruvic Acid / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002247:Carbon Isotopes; D019289:Pyruvic Acid; D000409:Alanine