Arterial Spin Labeling (ASL) fMRI: Advantages, Theoretical Constrains and Experimental Challenges in Neurosciences

Figure 3

CBF images from three simulation data sets: (a) homogenous gray matter CBF, (b) superimposed spatially sinusoidal fluctuation, and (c) localized regions of hypo- and hyperperfusion. CBF images from conventional CASL (3rd column) are compared with those from PVE correction performed in the time domain [41] (4th column) [40], and PVE correction done spatially with a small and a large kernel size (columns 5th and 6th, resp.). Note that the time-domain PVE (4th column) retains the spatial features of the true hypo/hyperperfused regions (2nd column) whereas the spatially applied PVE method has a smoothing effect that increases with the size of the kernel. Figure was taken without modification from Chappell et al. [53].