Imaging: arterial spin labelling

Penn Research Permits First-ever Visualization Of Psychological Stress In The Human Brain: "To date, most fMRI studies have indirectly measured changes in cerebral blood-flow and metabolism induced by neural activation, using a technique that is sensitive to the oxygenation levels in blood. "The fMRI technique employed in our study -- arterial spin labeling -- can measure cerebral flood-flow directly," states John A. Detre, MD, Associate Professor of Neurology and Radiology, and senior author of the study. "This technique is very similar to PET (positron emission tomography) scanning, except that it's entirely non-invasive -- without the need for injections or radioactivity. In this elegant technique, water molecules in subjects' own blood are 'tagged' by the magnet and used as the natural contrast agent to measure cerebral blood-flow." Researchers at Penn's Center for Functional Neuroimaging have been at the forefront of the development of this technique, and its applications to imaging brain-function during cognitive and emotional processes."