title: Proton magnetic resonance spectroscopic imaging in children with recurrent primary brain tumors.
abstract: OBJECTIVE
  Proton magnetic resonance spectroscopic imaging ((1)H-MRSI) is a noninvasive technique for spatial characterization of biochemical markers in tissues. We measured the relative tumor concentrations of these biochemical markers in children with recurrent brain tumors and evaluated their potential prognostic significance.
  
  
  METHODS
  (1)H-MRSI was performed on 27 children with recurrent primary brain tumors referred to our institution for investigational drug trials. Diagnoses included high-grade glioma (n = 10), brainstem glioma (n = 7), medulloblastoma/peripheral neuroectodermal tumor (n = 6), ependymoma (n = 3), and pineal germinoma (n = 1). (1)H-MRSI was performed on 1. 5-T magnetic resonance imagers before treatment. The concentrations of choline (Cho) and N-acetyl-aspartate (NAA) in the tumor and normal brain were quantified using a multislice multivoxel method, and the maximum Cho:NAA ratio was determined for each patient's tumor.
  
  
  RESULTS
  The maximum Cho:NAA ratio ranged from 1.1 to 13.2 (median, 4.5); the Cho:NAA ratio in areas of normal-appearing brain tissue was less than 1.0. The maximum Cho:NAA ratio for each histologic subtype varied considerably; approximately equal numbers of patients within each tumor type had maximum Cho:NAA ratios above and below the median. Patients with a maximum Cho:NAA ratio greater than 4.5 had a median survival of 22 weeks, and all 13 patients died by 63 weeks. Patients with a Cho:NAA ratio less than or equal to 4.5 had a projected survival of more than 50% at 63 weeks. The difference was statistically significant (P =.0067, log-rank test).
  
  
  CONCLUSIONS
  The maximum tumor Cho:NAA ratio seems to be predictive of outcome in children with recurrent primary brain tumors and should be evaluated as a prognostic indicator in newly diagnosed childhood brain tumors.
authors.affiliation: Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD, USA. warrenk@exchange.nih.gov
authors.forename: K E
authors.initials: KE
authors.lastname: Warren
authors.forename: J A
authors.initials: JA
authors.lastname: Frank
authors.forename: J L
authors.initials: JL
authors.lastname: Black
authors.forename: R S
authors.initials: RS
authors.lastname: Hill
authors.forename: J H
authors.initials: JH
authors.lastname: Duyn
authors.forename: A A
authors.initials: AA
authors.lastname: Aikin
authors.forename: B K
authors.initials: BK
authors.lastname: Lewis
authors.forename: P C
authors.initials: PC
authors.lastname: Adamson
authors.forename: F M
authors.initials: FM
authors.lastname: Balis
mesh_terms: D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009364:Neoplasm Recurrence, Local; D010865:Pilot Projects; D011379:Prognosis; D011522:Protons
chemical_list: D014408:Biomarkers, Tumor; D011522:Protons