title: Age-dependent normal values of T2* and T2' in brain parenchyma.
abstract: OBJECTIVE
  Physiologic age-related T2* and T2' values are required as reference for comparison with disease-related deviations. In our study, T2* and T2' values (T2 values as control) were determined with MR imaging in healthy subjects to determine standard values and investigate age-related changes.
  
  
  METHODS
  Data of 50 patients without intraparenchymal pathology and 10 acute stroke patients who underwent MR imaging including a T2 and T2* sequence with 3 echotimes were included. After calculation of T2*, T2', and T2 maps, the values of gray matter (GM) and white matter (WM) for each hemisphere were measured in 6 distinct regions of interest (ROIs).
  
  
  RESULTS
  There was a negative correlation between age and T2* values in the caudate nucleus (r = -0.34 Pearson correlation; P = .001) and lentiform nucleus (r = -0.67; P = .001) and a positive correlation in the occipital (r = 0.41; P = .001) and subcortical (r = 0.45; P = .001) WM. An age dependency for T2' values was only found for the caudate (r = -0.35; P = .001) and lentiform nucleus (r = -0.69; P = .001). T2' values in acute stroke were lower than normal in all patients with stroke.
  
  
  CONCLUSIONS
  Decrease in T2' and T2* values in GM and increase of T2* values in WM correlate with the progress of brain aging. Explanations for decreasing T2' and T2* values include iron deposition in the caudate and lentiform nucleus. In contrast to T2* values, there is no association of T2' values with the degree of leukoaraiosis. These age-dependent values can be used as a reference in neurovascular diseases and for the discussion of functional MR imaging data.
authors.affiliation: Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. s.siemonsen@uke.uni-hamburg.de
authors.forename: S
authors.initials: S
authors.lastname: Siemonsen
authors.forename: J
authors.initials: J
authors.lastname: Finsterbusch
authors.forename: J
authors.initials: J
authors.lastname: Matschke
authors.forename: A
authors.initials: A
authors.lastname: Lorenzen
authors.forename: X-Q
authors.initials: XQ
authors.lastname: Ding
authors.forename: J
authors.initials: J
authors.lastname: Fiehler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D001921:Brain / Q000033:anatomy & histology*; D002648:Child; D005260:Female; D005858:Germany; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods* / Q000592:standards*; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards*; D008297:Male; D008875:Middle Aged; D012016:Reference Values