title: Proton-decoupled 31P MRS in untreated pediatric brain tumors.
abstract: Proton-decoupled (31)P and (1)H MRS was used to quantify markers of membrane synthesis and breakdown in eight pediatric patients with untreated brain tumors and in six controls. Quantitation of these compounds in vivo in humans may provide important indicators for tumor growth and malignancy, tumor classification, and provide prognostic information. The ratios of phosphoethanolamine to glycerophosphoethanolamine (PE/GPE) and phosphocholine to glycerophosphocholine (PC/GPC) were significantly higher in primitive neuroectodermal tumors (PNET) (16.30 +/- 5.73 and 2.97 +/- 0.93) when compared with controls (3.42 +/- 1.62, P < 0.0001 and 0.45 +/- 0.13, P < 0.0001) and with other tumors (3.93 +/- 3.42, P < 0.001 and 0.65 +/- 0.30, P < 0.0001). Mean PC/PE was elevated in tumors relative to controls (0.48 +/- 0.11 versus 0.24 +/- 0.05, P < 0.001), but there was no difference between PNET and other tumors. Total choline concentration determined with quantitative (1)H MRS was significantly elevated (4.78 +/- 3.33 versus 1.73 +/- 0.56 mmol/kg, P < 0.05), whereas creatine was reduced in tumors (4.89 +/- 1.83 versus 8.28 +/- 1.50 mmol/kg, P < 0.05). A quantitative comparison of total phosphorylated cholines (PC+GPC)/ATP measured with (31)P MRS and total choline measured with (1)H MRS showed that in tumors a large fraction of the choline signal (>54 +/- 36%) was not accounted for by PC and GPC. The fraction of unaccounted choline was particularly large in PNET (>78 +/- 7%). The pH of tumor tissue was higher than the pH of normal brain tissue (7.06 +/- 0.03 versus. 6.98 +/- 0.03, P < 0.001).
authors.affiliation: Department of Radiology, Childrens Hospital Los Angeles, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Albers
authors.forename: Mark D
authors.initials: MD
authors.lastname: Krieger
authors.forename: Ignacio
authors.initials: I
authors.lastname: Gonzalez-Gomez
authors.forename: Floyd H
authors.initials: FH
authors.lastname: Gilles
authors.forename: J Gordon
authors.initials: JG
authors.lastname: McComb
authors.forename: Marvin D
authors.initials: MD
authors.lastname: Nelson
authors.forename: Stefan
authors.initials: S
authors.lastname: Blüml
mesh_terms: D001921:Brain / Q000378:metabolism*; D001932:Brain Neoplasms / Q000737:chemistry / Q000175:diagnosis*; D016022:Case-Control Studies; D002648:Child; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D004983:Ethanolamines / Q000378:metabolism; D005260:Female; D005997:Glycerylphosphorylcholine; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010767:Phosphorylcholine / Q000378:metabolism
chemical_list: D004983:Ethanolamines; D010714:Phosphatidylethanolamines; D010767:Phosphorylcholine; C002449:glycerophosphoethanolamine; D005997:Glycerylphosphorylcholine; C005448:phosphorylethanolamine; D003401:Creatine; D002794:Choline