Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

ASL is an fMRI method that maps cerebral blood (CBF), which is a key parameter of brain physiology. In ASL, flow-weighted images are computed by subtracting a “labeled” image from a contiguously acquired unlabeled control image. The difference is then converted to a CBF image using partial volume (PV) maps obtained from the segmentation of the anatomical T1w image. It follows that the quality of ASL data is dependent on the quality of motion correction and coregistration of the high-resolution T1w image to the low-resolution ASL. We tested whether applying brain-extraction on the low-resolution ASL would improve both these processes. The test was performed on 8 patients with carotid occlusive disease. Improvement in motion realignment was defined as % change averaged over the 6 degrees of freedom and across patients; improvement in coregistration was assessed as a difference in the mutual information (MI) value between the T1w and extracted and original ASL, respectively. There was a noticeable effect of brain extraction on both realignment and coregistration.