Imaging Brain Oxygenation with MRI Using Blood Oxygenation Approaches: Methods, Validation, and Clinical Applications

Results from a multiparametric qBOLD approach. A, MR imaging estimates of SO₂ as a function of directly measured SvO₂ of the sagittal sinus in rats. Squares, triangles, and diamonds represent rats under conditions of hyperoxia, normoxia, and hypoxia, respectively. B, Representative T2-weighted images and SO₂ maps in control and challenge conditions in 2 rats. Adapted from Christen et al.²¹

Parametric maps obtained with a quantitative BOLD approach by using a multiecho gradient-echo and spin-echo echo-planar imaging method in a healthy subject (A) and a patient with stroke (B). High OEF can be observed in the affected region of the patient with stroke (white arrow). This method holds promise to evaluate the brain oxygenation status in a rapid fashion, which is critical in the acute stroke work-up. Adapted from Christen et al.³⁷

Oxygen-sensitive MR imaging in the setting of cerebrovascular challenge during a 2-minute inhalation of carbogen gas (95% O₂, 5% CO₂). Images were acquired by using a multiple spin- and gradient-echo pulse sequence that enables the measurement of T2* and T2* with high temporal resolution. Note the increase in signal corresponding to decreased T2 and T2* during carbogen inhalation (gray column).

Quantitative magnetic susceptibility mapping in a volunteer at 7T. A and B, Gradient-echo weighted images. C and D, Corresponding magnetic susceptibility maps. E, Maximum intensity projection of the magnetic susceptibility maps over a 20-mm slab. Courtesy of Drs D. Qiu and M. Moseley, Stanford University.