title: Lithium, gray matter, and magnetic resonance imaging signal.
abstract: BACKGROUND
  Magnetic resonance imaging studies have reported that lithium can increase the volume of gray matter in the human brain, a finding that has been ascribed to the established neurotrophic or neuroprotective effects of the drug. Lithium, however, might directly influence the intensity of the magnetic resonance signal so it is possible that the volumetric findings are artifactual, essentially a consequence of altered image contrast.
  
  
  METHODS
  Anatomical and quantitative magnetic resonance scans were acquired on 31 healthy young men before and after taking either lithium or placebo for 11 days. Brain volume change was derived with two established techniques: voxel-based morphometry (a statistical approach using signal intensity to segment images into tissue types), and Structural Image Evaluation, using Normalization, of Atrophy (a technique that operates by detecting changes in the position of the boundaries of the brain). In a subgroup (n = 12), tissue-specific magnetic resonance relaxation times were compared before and after lithium with quantitative T1-mapping techniques.
  
  
  RESULTS
  Voxel-based morphometry revealed that gray matter volume was increased by lithium but not placebo (p = .001), whereas Structural Image Evaluation, using Normalization, of Atrophy showed no difference between lithium and placebo (p = .23). Taking lithium reduced the T1 relaxation of the gray matter only (p = .008).
  
  
  CONCLUSIONS
  Magnetic resonance images of the brain differ before and after lithium, but this difference might derive from a change in the characteristics of the signal rather than a tangible increase in volume.
authors.affiliation: Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom. david.cousins@ncl.ac.uk
authors.forename: David A
authors.initials: DA
authors.lastname: Cousins
authors.forename: Benjamin
authors.initials: B
authors.lastname: Aribisala
authors.forename: I
authors.initials: I
authors.lastname: Nicol Ferrier
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Blamire
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects*; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016651:Lithium Carbonate / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000494:pharmacology
chemical_list: D018696:Neuroprotective Agents; D016651:Lithium Carbonate