Assessment of diffuse Lewy body disease by 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET)

BACKGROUND: Lewy body disease is, after Alzheimer's disease, the second most common cause of senile degenerative dementia with progressive cognitive deterioration, fluctuation of cognitive and motoric functions and psychotic symptoms. It is characterized histologically by the occurrence of Lewy bodies in allocortical, neocortical and subcortical structures. The aim of this study was to measure the cortical glucose metabolism using FDG PET (2-[18F]fluoro-2-deoxy-D-glucose position emission tomography) compared to normal subjects. PATIENTS AND METHODS: Five patients (5 m, mean age 75 y) with clinically suspected diffuse Lewy body disease (DLB) were studied with FDG PET. PET studies of the head were performed with a Siemens ECAT-ART PET-scanner with attenuation correction using 137-Cs point sources. RESULTS: We found the same distribution pattern of diffuse glucose hypometabolism in the entire cortical region with relative sparing of the primary sensory-motor cortex in all the patients. The few cases reported in the literature so far describe findings similar to ours. CONCLUSION: The pattern of diffuse glucose hypometabolism in the entire cortex including the occipital region seems to be a typical feature of DLB that is distinctive from dementia of Alzheimer's disease

Amyloid PET and MRI in Alzheimer's Disease and Mild Cognitive Impairment

The neurodegenerative disorder Alzheimer's disease (AD) is the most common form of dementia. It is characterized by progressive impairment of cognitive functions and behavior. To distinguish clinically AD from other forms of dementia is an ongoing challenge. In addition, although mild cognitive impairment (MCI) is recognized as a risk factor for dementia, it remains a challenge to predict on an individual level who will convert to become demented. Amyloid beta (A beta) is one of the crucial pathological findings in AD. Recently, amyloid tracers for PET imaging have been developed successfully which may offer the unique possibility for measuring fibrillar A beta load in the living brain. Therefore, in the near future positron emission tomography (PET) may become an important tool for in vivo amyloid imaging contributing to early (differential) diagnosis as well as evaluation of treatment response in AD. Moreover, A beta may play a role in prediction the conversion of MCI to AD. In this paper we review the recent development of the molecular imaging technique PET and its different radiopharmaceuticals on the trail for imaging amyloid in AD and the conversion of MCI to A