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Brain Scan Technique Developed To Diagnose Alzheimer's Disease ------------------------------------------------------------------------ ------------------------------------------------------------------------ LONDON -- June 20, 1997 -- Diagnosis of Alzheimer's disease in the living can be only probable because samples of brain tissue need to be tested for a definitive diagnosis; a procedure usually only done at necropsy because the risks of such sampling in the living are unwarranted. However, in this week's issue of The Lancet, Dr. Masaomi Iyo and colleagues, from Japan, describe a non-invasive brain scanning technique which allows diagnosis of Alzheimer's disease in the living. Reduced activity of acetylcholinesterase, an enzyme in the brain, indicates the degeneration of a communication system, known as the central cholinergic system, in the brain. The scanning technique used by Iyo and colleagues takes advantage of this degeneration. Five patients with Alzheimer's disease and eight elderly controls were given an injection of a radioactive substance that binds to acetylcholinesterase in the blood. The participants then had their brains scanned by positron-emission tomography so that the radioactivity in their brains could be seen on a monitor. "All patients with Alzheimer's disease had multiple cortical (outer portion of the brain) regions with a reduced estimated acetylcholinesterase activity compared with control participants," the authors found. Each patient with Alzheimer's disease was found to have at least two cortical regions with significantly reduced acetylcholinesterase activity. Blood flow to the cerebral cortex of the brain is progressively reduced in Alzheimer's disease but "these results," the authors say, "suggest that biochemical changes may precede regional cerebral blood flow reduction", which must have implications for treatment strategies in the future. The authors conclude that "this method may be useful for elucidation of the mechanisms of Alzheimer's disease" and that it "may also be helpful in developing and assessing new therapies." ------------------------------------------------------------------------ More "Top of the News" stories ------------------------------------------------------------------------ ------------------------------------------------------------------------ ------------------------------------------------------------------------ ------------------------------------------------------------------------ This site is maintained by [log in to unmask] Please contact us with any comments, problems or bugs. All contents Copyright (c) 1995 P\S\L Consulting Group Inc. All rights reserved.