Since their introduction to medicine, Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) have greatly contributed to medical research and clinical practice. In particular, brain imaging with MRI and PET scans has led to important insights into both the normal and diseased brain. With increasingly advanced technology, scanning techniques, and clinical applications, brain imaging is a continuously evolving field. A web focus, presented by the Journal of Cerebral Blood Flow & Metabolism, compiles many of the most important research papers on the techniques and applications of cerebral MRI and PET imaging from Nature Neuroscience, Nature Medicine, NCP Neurology and Journal of Cerebral Blood Flow & Metabolism. There is free access to MRI & PET Imaging research for a limited time.