Figure 14.

(a–b) Morphological MRI scans showing location of fiducial markers indicating the location of NIRS/DOS probe which is then overlaid onto BOLD and ASL scans to define ROIs. As shown in (c), an MRI compatible NIRS/DOS probe was used for simultaneous data acquisition. (d) Group averaged responses from simultaneous ASL, BOLD and NIRS/DOS studies. Temporal evolution of NIRS/DOS measures of ΔTHC and ΔHbO₂ agree with ASL and ΔHb agrees with BOLD. Notice how ASL, ΔTHC and ΔHbO₂ maxima are earlier than BOLD and ΔHb maxima. ΔHb curve is shown inverted. Figure courtesy of D. A. Boas [474]).