Detection of Alzheimer’s Disease Using Amyloid Image or Alternative Neuroimaging Techniques

Detection of Alzheimer’s Disease Using Amyloid Image or

alternative Neuroimaging techniques

1. Introduction

A diversity of neurocognitive disorders is associated with the development of dementias, with the characteristics of neuronal dysfunctions and neuronal death eventually (Cedazo-Minguez, Winblad, 2009). Alzheimer’s disease (AD), first described by Alois Alzheimer in 1906, is the most common form of dementia, accounting for an estimated 60 to 80 percent of cases. It is characterized pathologically by the presence of β-amyloid plaques in the brain and eventually leads to impaired memory and other intellectual functions which interfere with normal functioning and impair quality of life. As one type of degenerative dementia, AD worsens as it progresses and eventually leads to death, since there is no cure for this disease. AD is diagnosed with high incidence rate in aging population (age>65), especially for people over 80, above which the prevalence exceeds 40%, although the less-prevalent early-onset Alzheimer’s can occur much earlier. Data indicates that this illness afflict about 26.6 million people in 2007 and this prevalence doubles steadily every decade as a larger population reaches the age of susceptibility (Brookmeyer et al, 2007). Therefore, extraordinary efforts will be spend on the prevention and treatment of Alzheimer’s disease.

Diagnosis of Alzheimer’s disease is usually achieved with first clinical features appearance occurred in later phage of disease, while its pathological changes begin decades before. This reduces the scope of useful interventions. Moreover, as a condition mainly assessed through clinical interpretation and neuropsychological testing, problems may exist due to variations in expertise of the clinicians involved (Ortiz-Teran et al, 2011). Additionally, there are no symptoms unique to AD in early diagnosis comparing to other relative disease (Craig-Schapiro et al, 2009). Furthermore, definitive diagnosis still relies on pathological evaluation at autopsy, though a battery of neuropsychological tests have been used in clinical to diagnose AD (Craig-Schapiro et al, 2009). All of these indicate the importance of identification of AD biomarkers, which allows detecting the preclinical changes at early stage in a more accurate and less invasive way as well as serving as a predictor of future disease progression and treatment response (Cedazo-Minguez, Winblad, 2010; Craig-Schapiro et al, 2009). Fortunately, in quest for biomarkers for AD conducted by multicenter biomarker trials worldwide in decades, specific ones have undergone a rapid evolution. Several technologies in imaging techniques have permitted great advances in improving the diagnosis and early detection of brain changes in vivo with higher sensitivity and specificity (Cedazo-Minguez, Winblad, 2010).

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