They say test has entered final clinical trial stages. And, if results continue to prove successful, it may be rolled out by the end of 2012, the 'Daily Mail' reported.
Until now, the only way to diagnose Alzheimer's was by ruling out other conditions such as cancer, depression or even a vitamin deficiency. Definitive confirmation came after death when brain samples containing high levels of beta amyloid plaques, the growths that characterise AD, are found.
But, now a new compound, called Flutemetamol, which highlights areas of the brain that are affected by the disease when scanned, is showing promising results in clinical trials, say the scientists.
The compound is injected into the arm and the patient exhibiting symptoms of Alzheimer's disease undergoes a positron emission tomography (PET) scan. If beta amyloid plaques are present in the brain, Flutemetamol makes them glow red, which confirms the patient has Alzheimer's disease.
In the second phase of the Flutemetamol study, 65 patients suffering with the disease and other degenerative mental-health conditions with less than a year to live were given Flutemetamol to see what brain scans revealed.
Post-mortem results showed that when a specialist alone tried to diagnose each case, 15 per cent of diagnoses were incorrect.
However, by using Flutemetamol there was only a seven per cent failure rate. Dr Francois Nicolas, director of neurology at GE Health, the company that is developing Flutemetamol, said: "What makes the results so revolutionary is that it makes both a correct and an earlier diagnosis possible for the first time.
"This could significantly increase the quality and even the length of a patient's life. Equally, those whose scan shows no signs of Alzheimer's disease can be given appropriate treatment they need too."
Experts have welcomed the research. Professor Leslie Findley, consultant neuroscientist at the Essex Neuroscience Unit, said: "The study is very positive but we don't know the full picture yet. To be able to detect Alzheimer's disease as a very early diagnosis really would be ground-breaking."