Interregional variation of longitudinal relaxation rates in human brain at 3.0 T: relation to estimated iron and water contents

Magn Reson Med. 2001 Jan;45(1):71-9. doi: 10.1002/1522-2594(200101)45:1<71::aid-mrm1011>;2-2.


In a study of interregional variation of the longitudinal relaxation rate (R(1)) in human brain at 3 T, R(1) maps were acquired from 12 healthy adults using a multi-slice implementation of the T one by multiple readout pulses (TOMROP) sequence. Mean R(1) values were obtained from the prefrontal cortex (0.567 +/- 0.020 sec(-1)), caudate head (0.675 +/- 0.019 sec(-1)), putamen (0.749 +/- 0.023 sec(-1)), substantia nigra (0.873 +/- 0.037 sec(-1)), globus pallidus (0.960 +/- 0.034 sec(-1)), thalamus (0.822 +/- 0.027 sec(-1)), and frontal white matter (1.184 +/- 0.057 sec(-1)). For gray matter regions other than the thalamus, R(1) showed a strong correlation (r = 0.984, P < 0.0001) with estimated regional nonheme iron concentrations ([Fe]). These R(1) values also showed a strong correlation (r = 0.976, P < 0.0001) with estimates of 1/f(w) obtained from MRI relative proton density measurements, where f(w) represents tissue water content. When white matter is included in the consideration, 1/f(w) is a better predictor of R(1) than is [Fe]. An analysis based on the fast-exchange two-state model of longitudinal relaxation suggests that interregional differences in f(w) account for the majority of the variation of R(1) across gray matter regions. Magn Reson Med 45:71-79, 2001.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Body Water*
  • Brain Chemistry*
  • Cerebral Cortex / chemistry
  • Female
  • Globus Pallidus / chemistry
  • Humans
  • Image Processing, Computer-Assisted
  • Iron / analysis*
  • Magnetic Resonance Imaging*
  • Male
  • Phantoms, Imaging
  • Putamen / chemistry
  • Thalamus / chemistry


  • Iron