Marwan Sabbagh, MD, FAAN, CCRI is the founder, Director and Senior Scientist at The Cleo Roberts Center of Clinical Research, Sun Health Research Institute.  The Sun Health Research Institute is a non-profit and conducts clinical trials in Neurology, Oncology, and Cardiology. With Dr. Sabbagh, the institute has conducted more than 30 clinical trials for Alzheimer's and Parkinson's diseases.  Dr. Sabbagh is also Associate Director of the Arizona Alzheimer's Disease Core Center, a clinical instructor in the Sun Health/St. Joseph's Hospitals Geriatric Fellowship Program, clinical assistant professor of neurosciences at the University of California-San Diego and a visiting scientist in the Department of Neurology at Mayo Clinic Scottsdale.  He has dedicated his career to finding a cure for Alzheimer's and other age-related neurodegenerative diseases.  Dr. Sabbagh has authored and co-authored more than 70 medical and scientific articles and has now published a book--The Alzheimer's Answer (Wiley, Feb 2008).

Marwan Sabbagh--

"The news by Leinonen et al to be published in an upcoming Archives of Neurology adds credence to a growing argument for use of amyloid imaging as a diagnostic tool for Alzheimer's Disease (AD). This area has gotten a lot of attention in the Alzheimer world of late. PET imaging has long been felt to show promise as a diagnostic tool for Alzheimer's. Until recently, the principal imaging compound was FDG. FDG is essentially radioactive sugar that shows areas that are metabolically active. Since the brain is a very metabolically active organ, PET with FDG shows that most areas are normally metabolically active. In AD, there is loss of metabolic activity in the parietal and temporal lobes of the brain as well as the posterior cingulate gyrus.

Researchers at UCLA showed that FDG PET was 93% accurate in detecting AD. Since that time, many clinicians have recommended including PET as a diagnostic tool. This recommendation has not been widely adopted. However, FDG PET has the limitation of only being a proxy of metabolic activity and does not detect specific AD pathology.

A breakthrough in imaging came about 5 years ago when doctors Mathis and Klunk at the University of Pittsburgh developed an imaging compound called Pittsburgh compound B (aka PIB) which was shown to label amyloid directly in the brain. This breakthrough has been revolutionary as we now have a surrogate marker of disease for AD. Presently researchers are attempting to understand how well PIB PET imaging predicts AD and how sensitive and specific the test is. It appears that PIB PET is highly sensitive. Present research is also focused on PIB positive cognitively normal individuals to determine whether PIB is a marker of future AD and also how well PIB correlates with disease progression.

The Leinonen finding is very telling. Normal pressure hydrocephalus (NPH) is another type of dementia. Although it can overlap with AD, the treatment is different. Therefore, it would be important to identify people who have comorbid AD and NPH as they might not benefit as much from surgical treatments for NPH. PIB PET might help to achieve this. Further, this study also gives much needed pathological correlation to imaging findings.

PIB PET is a huge step forward to being able to diagnose AD without an autopsy. There are other imaging compounds in development including Avid AV45 and FDNNP from UCLA."

Alzheimer's Disease Studies Show Positive Results