Abstract: Objective  To investigate the diagnostic and differential diagnostic value of ¹¹C-Pittsburgh compound B (¹¹C-PIB) positron emission tomography (PET) imaging for Alzheimer's disease (AD), mild cognitive impairment (MCI) and non- Alzheimer's disease induced cognitive impairment (NAD) by qualitatively and semi quantitatively evaluating the degree of β-amyloid (Aβ）deposition in the brain.  Methods  AD patients (AD, n=36), mild cognitive impairment (MCI, n=20), non-AD induced cognitive impairment (NAD, n=19), and normal controls (NC, n=10) admitted to the Department of Neurology, Xuanwu Hospital, Capital Medical University in 2022 were retrospectively analyzed. All 85 subjects underwent ¹¹C-PIB PET imaging. First, Aβ Negative or positive deposition was qualitatively estimated, and then taking the brainstem as the reference brain area, the maximum standardized uptake value ratio(SUVRmax）of the frontal, parietal, temporal, and occipital lobes of the cerebral cortex Aβ was semi-quantitative measured, and the differences of SUVRmax among AD, MCI, NAD. and NC groups were analyzed. Results  Qualitative judgment showed that there were significant differences between AD group ,NC group, and other groups , but no significant difference between MCI group and NAD group. Semi quantitative analysis showed that for all brain regions (frontal lobe, parietal lobe, temporal lobe, occipital lobe), the SUVRmax value of AD group was significantly higher than that of the other three groups, with a statistically significant difference. In all brain regions, the SUVRmax value of NC group was the lowest, but there was no significant difference in SUVRmax among MCI group,NAD and NC group. Conclusion  Both qualitative and semi quantitative analysis of ¹¹C-PIB PET imaging were of high value in the diagnosis of AD, and semi quantitative analysis showed certain significance in differentiating AD and MCI.

Key words: Alzheimer's disease, amyloid protein, ¹¹C-PIB PET