title: Proton magnetic resonance spectroscopic imaging to differentiate between nonneoplastic lesions and brain tumors in children.
abstract: OBJECTIVE
  To investigate whether in vivo proton magnetic resonance spectroscopic imaging (MRSI) can differentiate between 1) tumors and nonneoplastic brain lesions, and 2) high- and low-grade tumors in children.
  
  
  METHODS
  Thirty-two children (20 males and 12 females, mean age = 10 +/- 5 years) with primary brain lesions were evaluated retrospectively. Nineteen patients had a neuropathologically confirmed brain tumor, and 13 patients had a benign lesion. Multislice proton MRSI was performed at TE = 280 msec. Ratios of N-acetyl aspartate/choline (NAA/Cho), NAA/creatine (Cr), and Cho/Cr were evaluated in the lesion and the contralateral hemisphere. Normalized lesion peak areas (Cho(norm), Cr(norm), and NAA(norm)) expressed relative to the contralateral hemisphere were also calculated. Discriminant function analysis was used for statistical evaluation.
  
  
  RESULTS
  Considering all possible combinations of metabolite ratios, the best discriminant function to differentiate between nonneoplastic lesions and brain tumors was found to include only the ratio of Cho/Cr (Wilks' lambda, P = 0.012; 78.1% of original grouped cases correctly classified). The best discriminant function to differentiate between high- and low-grade tumors included the ratios of NAA/Cr and Cho(norm) (Wilks' lambda, P = 0.001; 89.5% of original grouped cases correctly classified). Cr levels in low-grade tumors were slightly lower than or comparable to control regions and ranged from 53% to 165% of the control values in high-grade tumors.
  
  
  CONCLUSIONS
  Proton MRSI may have a promising role in differentiating pediatric brain lesions, and an important diagnostic value, particularly for inoperable or inaccessible lesions.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland 21205, USA.
authors.forename: Roula
authors.initials: R
authors.lastname: Hourani
authors.forename: Alena
authors.initials: A
authors.lastname: Horská
authors.forename: Sait
authors.initials: S
authors.lastname: Albayram
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Brant
authors.forename: Elias
authors.initials: E
authors.lastname: Melhem
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Cohen
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burger
authors.forename: John D
authors.initials: JD
authors.lastname: Weingart
authors.forename: Benjamin
authors.initials: B
authors.lastname: Carson
authors.forename: Moody D
authors.initials: MD
authors.lastname: Wharam
authors.forename: Peter B
authors.initials: PB
authors.lastname: Barker
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000175:diagnosis* / Q000473:pathology; D001707:Biopsy, Needle; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D018237:Germinoma / Q000175:diagnosis* / Q000473:pathology; D005910:Glioma / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D009367:Neoplasm Staging; D012189:Retrospective Studies; D012680:Sensitivity and Specificity