Brain scans of people with mild cognitive impairment show signs of early Alzheimer's disease

Brain scans of people with mild cognitive impairment (MCI) show signs of early Alzheimer's disease, according to a study published in the May 8, 2007, issue of Neurology, the scientific journal of the American Academy of Neurology.

For the study, PET scans were performed on the brains of 13 elderly men and women with mild cognitive impairment (MCI) and 14 elderly people without memory problems. The scans were used to measure uptake of PIB, which is an imaging agent that allows doctors to see and measure abnormal protein aggregation growth, otherwise known as amyloid plaque, in the brain. Abnormal protein aggregation growth is a signature of Alzheimer's disease. Until recently, Alzheimer's disease couldn't be officially diagnosed until after death with an autopsy.

The study found people with MCI had as much as 39 percent more PIB uptake in some parts of the brain than people without MCI. And about half of the MCI patients had PIB uptake in the Alzheimer's disease range.

"This pattern of increased PIB in patients with MCI resembles what's seen in Alzheimer's disease and is suggestive of an early Alzheimer's disease process," said study author Juha O. Rinne, MD, PhD, with the University of Turku in Turku, Finland, and Fellow of the American Academy of Neurology. "Our findings are similar to what's seen in post-mortem studies in which abnormal protein aggregation growth is found in people who had been diagnosed with probable Alzheimer's disease."

Rinne says larger studies and extended follow-up is needed since identifying people with MCI who have abnormal protein aggregation growth will become increasingly important as treatments affecting such plaque amyloid accumulation become available.