Measurement of Cerebral Oxygen Extraction Fraction Using Quantitative BOLD Approach: A Review

Abstract

Quantification of brain oxygenation and metabolism, both of which are indicators of the level of brain activity, plays a vital role in understanding the cerebral perfusion and the pathophysiology of brain disorders. Magnetic resonance imaging (MRI), a widely used clinical imaging technique, which is very sensitive to magnetic susceptibility, has the possibility of substituting positron emission tomography (PET) in measuring oxygen metabolism. This review mainly focuses on the quantitative blood oxygenation level-dependent (qBOLD) method for the evaluation of oxygen extraction fraction (OEF) in the brain. Here, we review the theoretic basis of qBOLD, as well as existing acquisition and quantification methods. Some published clinical studies are also presented, and the pros and cons of qBOLD method are discussed as well.

Keywords: Brain diseases; Oxygen extraction fraction; Quantitative BOLD; Static dephasing regime.

Fig. 1

The comparison of the relative errors ${\epsilon }_{\mathit{DBV}}$ as functions of echo time (TE). Solid lines: one-compartment model; dashed lines: two-compartment model (i) tissue and ISF/CSF; dotted lines: two-compartment model (ii) tissue and blood; dash–dotted lines: three-compartment model (iii) tissue, CSI/CSF, and blood [Adapted from Wang et al. (2013) with permission]

Fig. 2

The simulation diagram of vessel system. R_S = 900 μm, Number of vessels = 100

Fig. 3

Parameter maps from the diffusive qBOLD; a DBV, b OEF, c $T_2^t$, d D values from a co-registered DWI. [Adapted from Dickson et al. (2010) with permission]

Fig. 4

Schematic of the qBOLD model describing the transverse MR signal decay in the presence of a blood vessel network. ${\mathrm{R}}_2^{{}^{\prime }}$ is inferred from the long-term regime, and DBV is inferred from the mismatch between the linear intercept of this fit and spin echo signal (t = 0 ms). [Modified from Stone and Blockley (2017)]

Fig. 5

Sequence diagram of the qBOLD approach sequence; a two-dimensional, multi-echo gradient and spin echo sequence, b two-dimensional three-echo asymmetric SE echo-planar imaging (EPI) sequence

Fig. 6

Overview of MqBOLD sequences and derived parameters. Representative images of a 72-year-old male patient with acute ischemic stroke (2 h post-onset case)

Fig. 7

An example from a patient with a right middle cerebral artery stroke. The OMI map two hours after onset was in column (a), with an OMI threshold of 0.28 to differentiate infarct core from penumbra, and 0.4 to differentiate the penumbra from tissue not-at-risk. The second MRI scan, six hours after onset, further subdivided the penumbra (b). Survived (green) or died (red) tissues in column (c) were determined by FLAIR imaging after 1 month (d). [Adapted from An et al. (2015) with permission]

Fig. 8

Averaged OEF maps before (a), and after (b) CTT. Left side indicates the averaged maps. Right side shows the regions above the OEF thresholds. The median proportion of hemispheric volume above the OEF threshold decreased after transfusion (c). [Adapted from Guilliams et al. (2018) with permission]

Fig. 9

A patient with a glioblastoma IDH1 wt showing features of the glycolytic dominated phenotype. The large areas of the lesions with both very high mitochondrial oxygen tension (mitoPO2) and very high micro-vessel type indicator (MTI) values, representing the presence of glycolysis, and proliferation of functional neovascularization, respectively. [Adapted from Stadlbauer et al. (2018) with permission]