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Abstract

Arterial Spin Labeling (ASL) is a magnetic resonance imaging (MRI) method to map the cerebral blood flow (CBF). ASL present a non-invasive alternative to the contrast agent and ASL techniques are capable of providing quantitative information about local tissue blood
flow by tracking the inflow of magnetically labeled arterial blood into an imaging slice. The delivery of the tagged water to each image voxel is measured. Because ASL is completely noninvasive, the tagging can be repeated many times to obtain a high signal-to-noise ratio (SNR). ASL produces perfusion maps of human brain with higher spatial and temporal resolution than any other existing technique. Furthermore, ASL techniques are an important tool to study the physiological basis of functional neuroimaging techniques such as BOLD signal. Retinotopy describes the spatial organization of the neuronal responses to visual stimuli. In many locations within the brain, adjacent neurons have receptive fields that include slightly different, but overlapping portions of the visual field. The position of the center of these receptive fields forms an orderly sampling mosaic that covers a portion of the visual field. fMRI retinotopic mapping provides detailed information about the correspondence between the visual field and its cortical representation in the individual subjects. In this study, we present the possibilty to map the retinotopic organization of the visual areas by using
perfusion contrast measured with the arterial spin labeling fMRI.