Brain scan may finally detect Alzheimer's early

THERE is only one way to know for sure that a person has Alzheimer's disease. A pathologist, examining the brain after death, would see microscopic black freckles - plaque - sticking to brain slices.
Without evidence of plaque, a person with memory loss cannot be diagnosed with the disease. There is no treatment to stop or slow the progress of Alzheimer's, but every major drug company has new experimental drugs it hopes will work. The questions though, are who should be getting the drugs, and who really has Alzheimer's or is developing it?
But findings of tests on hospice patients show that a start-up medical technology company may have overcome one of the biggest obstacles in diagnosing Alzheimer's. It has developed a dye that allows brain scans to reveal the plaque building in the brains of people with the disease.
The findings will be presented at an international meeting of the Alzheimer's Association in Honolulu on July 11. But they must still be confirmed and approved by the US Food and Drug Administration.
Five years ago Dr Daniel Skovronsky left academia and formed Avid Radiopharmaceuticals in Philadelphia to pursue his idea for brain scans to show the telltale plaque.
He and his team had developed a dye that could get into the brain and stick to plaque. They labelled the dye with a commonly used radioactive tracer and used a PET scanner to directly see plaque in a living person's brain.
If the findings hold up, it will mean that for the first time doctors would have a reliable way to diagnose the presence of Alzheimer's in patients with memory problems.
And researchers would have a way to figure out whether drugs are slowing or halting the disease, a step that ''will change everyone's thinking about Alzheimer's in a dramatic way'', said Dr Michael Weiner of the University of California, San Francisco.
To test the procedure Dr Skovronsky's team designed a study with hospice patients. They sought the patients' permission to have scans while still alive and then brain autopsies after death to see if the scans showed just what a pathologist would see.
Some predicted his study would be impossible, but the FDA said it wanted proof the plaque on PET scans was the same as plaque in a brain autopsy. Finally, on May 14, 35 patients had been scanned and autopsied. The Avid study was complete.
''This is going to have a big impact on Alzheimer's disease, guys,'' Dr Skovronsky told his staff that day.