Cerebral oxygen extraction fraction and cerebral venous blood volume measurements using MRI: effects of magnetic field variation

Magn Reson Med. 2002 May;47(5):958-66. doi: 10.1002/mrm.10148.


The presence of magnetic background field inhomogeneity (DeltaB) may confound quantitative measures of cerebral venous blood volume (vCBV) and cerebral oxygen extraction fraction (MR_OEF) with T2*-based methods. The goal of this study was to correct its effect and obtain more accurate estimates of vCBV and MR_OEF. A 3D high-resolution gradient echo sequence was employed to obtain DeltaB maps by two algorithms. The DeltaB maps were then used to recover the signal loss in images acquired by a 2D multiecho gradient echo / spin echo sequence. Finally, both quantitative estimates of MR_OEF and vCBV were obtained from the DeltaB- corrected 2D multiecho gradient echo / spin echo images. A total of 12 normal subjects were studied. An overestimated vCBV was observed in the brain (4.29 +/- 0.78%) prior to DeltaB correction, while the measured vCBV was substantially reduced after DeltaB correction. Whole brain vCBV of 2.97 +/- 0.44% and 2.68 +/- 0.47% were obtained by the two different DeltaB correction methods, in excellent agreement with the reported results in the literature. Furthermore, when MR_OEF was compared with and without DeltaB correction, no significant differences (P = 0.467) were observed. The ability to simultaneously obtain vCBV and MR_OEF noninvasively may have profound clinical implications for the studies of cerebrovascular disease.

Publication types

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

MeSH terms

  • Algorithms
  • Blood Volume Determination / methods*
  • Brain / metabolism*
  • Cerebrovascular Circulation / physiology*
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Magnetics
  • Models, Theoretical
  • Oxygen Consumption / physiology*
  • Phantoms, Imaging
  • Veins / physiology