title: Long-term normal-appearing brain tissue monitoring after irradiation using proton magnetic resonance spectroscopy in vivo: statistical analysis of a large group of patients.
abstract: OBJECTIVE
  The aim of this study was to detect the non-neoplastic white-matter changes vs. time after irradiation using 1H nuclear magnetic resonance (NMR) spectroscopy in vivo.
  
  
  METHODS
  A total of 394 1H MR spectra were acquired from 100 patients (age 19-74 years; mean and median age, 43 years) before and during 2 years after radiation therapy (the mean absorbed doses calculated for the averaged spectroscopy voxels are similar and close to 20 Gy).
  
  
  RESULTS
  Oscillations were observed in choline-containing compounds (Cho)/creatine and phosphocreatine (Cr), Cho/N-acetylaspartate (NAA), and center of gravity (CG) of the lipid band in the range of 0.7-1.5 ppm changes over time reveal oscillations. The parameters have the same 8-month cycle period; however the CG changes precede the other by 2 months.
  
  
  CONCLUSIONS
  The results indicate the oscillative nature of the brain response to irradiation, which may be caused by the blood-brain barrier disruption and repair processes. These oscillations may influence the NMR results, depending on the cycle phase in which the NMR measurements are performed in. The earliest manifestation of radiation injury detected by magnetic resonance spectroscopy is the CG shift.
authors.affiliation: Department of Medical Physics, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland. lukasz.matulewicz@io.gliwice.pl
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Matulewicz
authors.forename: Maria
authors.initials: M
authors.lastname: Sokół
authors.forename: Anna
authors.initials: A
authors.lastname: Michnik
authors.forename: Jerzy
authors.initials: J
authors.lastname: Wydmański
mesh_terms: D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000503:physiopathology / Q000528:radiation effects; D001921:Brain / Q000378:metabolism / Q000528:radiation effects*; D001932:Brain Neoplasms / Q000532:radiotherapy; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D005910:Glioma / Q000532:radiotherapy; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D010725:Phosphocreatine / Q000378:metabolism; D011832:Radiation Injuries / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: D010725:Phosphocreatine; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline