June 10, 2011

Molecular Imaging For Alzheimer’s Disease

(Ivanhoe Newswire) -- Researchers across the world are advancing positron emission tomography (PET) as an effectual method of early detection for Alzheimer's disease, a currently incurable and fatal neurological disorder.  Three novel studies are providing insights into the development of Alzheimer's disease while opening the door to future clinical screening and treatments.

An estimated 18 million people worldwide are currently living with Alzheimer's disease "” a number projected to almost double by 2025, according to the World Health Organization.

"The aging population around the world is escalating exponentially.  From a macro perspective, amyloid imaging with PET scans can help to ascertain the likelihood that individuals will deteriorate cognitively within a few years, thereby enabling more efficient channeling of health care resources," which Kevin Ong, MD, lead author of a presented study and a research scientist at Austin Hospital, Melbourne, Australia, was quoted as saying.

"From a micro perspective, planning and lifestyle modifications are possible for individuals who seek screening for Alzheimer's disease."

Molecular imaging of Alzheimer's disease is focused on detecting and analyzing the arrangement of a naturally occurring protein in the brain known as beta-amyloid, which researchers now say is involved in the pathology of Alzheimer's.

"It turns out that increased amyloid is bad for cognition even in the healthy elderly," which Michael Devous, Sr., PhD, director of neuroimaging for the Alzheimer's Disease Center at UT Southwestern Medical Center, Dallas, Texas, was quoted as saying.

"If you look at working memory, processing speed or fluent reasoning, three critical general domains of cognition, the more amyloid you have the worse your performance, and that's after correcting for age."

Not only is this imperative for imaging the disease, but also it could furthermore prove to be the key to amyloid-associated therapies and vaccines.  Investigators caution that the preliminary stages of the disease can precede symptoms of dementia as much as a decade or more.  Imaging patients when they first show signs of mild cognitive impairment could be vital in determining their risk of future disease.

"For individuals who have already developed a measurable memory decline, a positive scan for amyloid is the most accurate predictor of progression to Alzheimer's disease," which Christopher Rowe, MD, a lead investigator for the Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging and professor of nuclear medicine at Austin Hospital, Victoria, Australia, was quoted as saying.

"Amyloid imaging with PET scans is expected to be widely available soon for clinical practice.  It will be an important new tool in the assessment of cognitive decline."

Three current studies involve numerous years of research based on hundreds of participants ranging widely in age, cognitive ability and stage of disease.  Results of these studies illustrate that amyloid plaques build up exceptionally slow, by an estimated two to three percent per year, and that they are frequently already present in healthy older individuals "” 12 percent of those in their 60s, 30 percent of those in their 70s and 55 percent in those over the age of 80.

Researchers estimate that amyloid imaging agents will be accessible for clinical use in less than 12 months.  These and further studies will continue to accumulate information in relation to the development of Alzheimer's disease, and possible treatments may ultimately cease and perchance even avert or undo damage in the brain as a result of Alzheimer's disease.

SOURCE: SNM's 58th Annual Meeting,  June 6, 2011