Evaluating the Remote Effects of Stroke With MRI and PET Scans

Patients with stroke sometimes have a condition called diaschisis, a loss of function in a part of the brain located some distance from the original stroke-injury site. Doctors do not know why this happens. The purpose of this study is to get a better understanding as to why diaschisis occurs by studying people who have experienced a stroke and people who have aged in good health. Forty-four participants who are older than 40 year of age will be enrolled in this study-18 healthy people and 26 stroke patients. They will have 3 to 4 study visits. The first visit will involve a medical history and a physical and neurological exam. Participants will then have a magnetic resonance imaging (MRI) scan, either on the first visit or on a later day. On the next visit, they will undergo a position emission tomography (PET) scan. Finally, they will return for another MRI scan.