Figure 4
From: Cerebral perfusion metrics calculated directly from a hypoxia-induced step change in deoxyhemoglobin
ΔR2* signal during reoxygenation in 2 voxels with different levels of noise. The images are screen captures from the step analysis computer program. The image on the left is representative of a noisy signal, with the image on the right a less noisy signal. The red line is the fit of the Gompertz function to the ΔR2* signal response to a step change in SaO2. The green line is fitted to the linear portion of the function and extended to baseline (top) and asymptote of oxygenated blood (bottom). The vertical yellow line is the reference time cursor used for all voxels to calculate blood arrival time. (The analysis method is described in “Methods” Fig. 11).
