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Cerebral oxygen extraction fraction and cerebral venous blood volume measurements using MRI: Effects of magnetic field variation
Author(s) -
An Hongyu,
Lin Weili
Publication year - 2002
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.10148
Subject(s) - gradient echo , nuclear magnetic resonance , spin echo , nuclear medicine , magnetic resonance imaging , echo time , cerebral veins , cerebral blood volume , cerebral blood flow , medicine , physics , radiology , cardiology
The presence of magnetic background field inhomogeneity (ΔB) may confound quantitative measures of cerebral venous blood volume (vCBV) and cerebral oxygen extraction fraction (MR_OEF) with T 2 * ‐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 ΔB maps by two algorithms. The ΔB 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 ΔB‐ 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 ΔB correction, while the measured vCBV was substantially reduced after ΔB correction. Whole brain vCBV of 2.97 ± 0.44% and 2.68 ± 0.47% were obtained by the two different ΔB correction methods, in excellent agreement with the reported results in the literature. Furthermore, when MR_OEF was compared with and without ΔB 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. Magn Reson Med 47:958–966, 2002. © 2002 Wiley‐Liss, Inc.