Scan, dye may help ID Alzheimer's

6/25/2010

NEW YORK - A company says it has overcome one of the biggest obstacles in diagnosing Alzheimer's disease. Dr. Daniel Skovronsky says his company has found a dye and a brain scan that, he said, can show the hallmark plaque building up in the brains of people with the disease.

The findings, which will be presented at an international meeting of the Alzheimer's Association in Honolulu July 11, must be confirmed and approved by the Food and Drug Administration. But if they 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.

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 like barnacles. Without plaque, a person with memory loss did not have the disease.

There is no treatment to stop or slow Alzheimer's, but every major drug company has experimental drugs it hopes will work. The questions, though, are who should get the drugs, and who really has Alzheimer's or is developing it?

Even at the best medical centers, doctors often are wrong. Twenty percent of people with dementia - a loss of memory and intellectual functions - who received a diagnosis of Alzheimer's did not have it.

Brain scans that showed plaque could help with fundamental questions.

Dr. Skovronsky thought he had a way to make scans work. He and his team had developed a dye that could get into the brain and stick to plaque. They labeled the dye with a commonly used radioactive tracer and used a PET scanner to directly see plaque in a living person's brain. But the technology and the dye itself were so new, they had to be rigorously tested.

Dr. Skovronsky, who left academia five years ago and formed Avid Radiopharmaceuticals to develop his radioactive dye, designed a study using hospice patients to prove it worked. Volunteers had brain scans using the dye, then the results were compared with autopsy results that showed which patients did and did not have Alzheimer's.