Abstract
Introduction The incidence of dementia in elderly population, aged 60 year or older, has been rapidly increasing. Dementia causes significant negative impacts on quality of lives, both in patients and families, constituting a huge socioeconomic burden and drawback in country’s development. Current diagnostic approach based on clinical symptoms and signs may not sufficient. Thus, early detection of amyloid deposition in the brain may play important role in accurate diagnosis, identifying patients at risk, planning for patient management and also leading to development the drug or procedure aimed for therapy or prevention of dementia.
Objectives To evaluate the use of F-18 amyloid PET scan in assessing brain amyloid deposition in Alzheimer’s disease, mild cognitive impairment and normal aging and the correlation between brain amyloid deposition in PET scan and results from neuropsychological test, MRI brain and F-18 FDG PET scan. We also aimed to evaluate the correlation between amyloid PET scan results and changes in neuropsychological test, MRI brain and F-18 FDG PET scan results.
Methods 1) Synthesis of F-18 flobetapir PET tracer 2) Initial clinical study in 43 eligible subjects including 22 normal elderly controls (HC), 12 MCI patients and 9 AD patients according to clinical diagnosis. All subjects were assessed by 1) clinical signs and symptoms and neuropsychological test, brain MRI, F-18 FDG PET and F-18 flobetapir PET scan of the brain within 6-week period. The images were then analyzed using visual and quantitative analyses.
Results The semi-automated synthesized F-18 flobetapir demonstrated equivalent characteristics to those of reported original compound; radiochemical yield of approximately 20%, pH of 6, half-life of 115.66 minutes, radiochemical purity > 95%, sterility and pyrogenicity were equivalent to drug for injection standard. Each synthesis could serve approximately 3 patients. Preliminary results of the clinical study in 17 of 43 eligible volunteers who had completed study protocol and test analysis found that F-18 flobetapir results in most of volunteers (n = 16 (94.12%) corresponded to the clinical diagnosis and neuropsychological test results, while MRI (Schelten’s rating scale) and F-18 FDG PET scan results corresponded with clinical diagnosis and neuropsychological test in 13 (76.47%) and 15 (88.24%) volunteers, respectively. The correlation of results between F-18 flobetapir and other tests showed that F-18 flobetapir tended to correlate with neuropsychological test in 16 (94.12%), MRI in 12 (70.59%) and F-18 FDG in 16 (94.12%) volunteers. So far, there was no detectable adverse effect in any subject.
Conclusion Our preliminary results found a very high correlation between amyloid PET scan using F-18 flobetapir and clinical diagnosis and neuropsychological test results, which was higher than in F-18 FDG PET and anatomical abnormality detected by MRI, respectively. However, correlation between amyloid PET scan results and changes in neuropsychological test, MRI brain and F-18 FDG PET scan results are still needed to be followed.
