Positron Emission Tomography (PET), a method of medical imaging, appears to be a successful non-invasive test for detecting the early stages of Alzheimer’s disease. Until now, doctors couldn’t be sure if a patients was suffering from the disease until the brain was examined after death in an autopsy.

The method developed by University of Pittsburgh researchers and used by Ville Leinonen of Finland's University of Kuopio and his colleagues, may help detect the presence of the brain plaques, including those made of the compound beta-amyloid, considered hallmarks for developing Alzheimer’s.

PET scanning uses a novel brain-imaging agent called Pittsburgh Compound B (PiB), which attaches to Alzheimer’s-related brain deposits. The chemical is injected into a vein before the scan.

Leinonen and his colleagues used PET scans on 10 people who had undergone a brain biopsy because of a suspected abnormal increase of cerebrospinal fluid in the brain, suspicious signs of a condition called normal-pressure hydrocephalus (NPH). The condition also causes mind and memory problems. Some patients showing symptoms of the condition have brain lesions characteristic of Alzheimer’s disease. After brain biopsy, which showed that six patients had beta-amyloid plaque, the patients underwent a 90-minute PET scan. They were previously injected with PiB.

All patients with beta-amyloid plaques had a higher uptake of the imaging compound compared to those without the abnormal proteins.

“This study supports the use of…PiB PET in the evaluation of beta-amyloid [deposits] in, for example, mild cognitive impairment, Alzheimer’s disease or normal-pressure hydrocephalus,” Leinonem said.

However, he agreed that more studies are needed to determine whether PET scanning can be used to diagnose Alzheimer’s disease.

The study’s findings appeared in the online issue of the Archives of Neurology and will be published in its October 2008 print issue.

There are currently 5.2 million Americans living with Alzheimer’s disease, a number expected to reach 7.7 million by 2030, as the baby boom generation ages, according to the advocacy group Alzheimer’s Association. There is no cure for the disease, as existing drugs can ease symptoms but do not stop it.