Measurement of cerebral nicotine receptor by positron-CT aiming at early diagnosis of Alzheimer's disease

Cerebral circulation of the patients with cerebrovascular disease were investigated using PET (Headtome-4, Shimadzu Seisakusho Ltd.) with an aim to detect dementia at an early stage and to evaluate its degree accurately. Cerebral circulation was assessed with the following indicators; cerebral blood flow (CBF), oxygen enhancement ratio (OER), cerebral metabolic rate for O2 (CMRO), ratio of CBF to cerebral blood volume (CBV). On the PET images, respective 16 regions were chosen to investigate the correlation between resting CBV and Diamox loading CBV as well as the correlation between resting OER and Diamox loading OER. Based on the values of DEF and CBF/CBV, 194 regions concerned were divided into 3 groups; 61 regions for normal group, 113 for group stage 1 and 20 for group 2. CBV was significantly different between normal and stage 1-groups, and stage 1- and stage 2-groups. And CBV decreased depending on the severity of the disease. Further, the correlation coefficients for DEF and CBV increase due to Diamox loading were 0.33, 0.050 and 0.680 for normal, stage 1- and stage 2- group, showing significance only in stage 2-group, showing significance only in stage 2-group. Thus, evaluation of the degree of cerebrovascular disease was found possible up to the moderate degree by cerebral SPECT. (M.N.)