Xiehe Yixue Zazhi (Mar 2022)
Comparative Study of 18F-FDG PET/CT Metabolic Alteration Patterns in Cerebral Amyloid Angiopathy and Alzheimer's Disease
Abstract
Objective To compare the metabolism pattern of the brain in patients with cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD), and to evaluate the value of brain imaging of 18F-fluorodeoxy glucose (FDG) positron emission tomography/computed tomography (PET/CT) in differentiating CAA and AD. Methods We retrospectively recruited patients with probable CAA (revised Boston diagnostic criteria) and AD of similar age from December 2020 to June 2021 at Peking Union Medical College Hospital. Patients with normal cognition that underwent 18F-FDG PET/CT during the same period were randomly included as controls. We performed visual analysis and quantitative analysis of PET/CT imaging in the three groups. Results Ten patients with probable CAA (CAA group), 10 patients with AD (AD group), and 11 control subjects with normal cognitive function (control group) that met the inclusion and exclusion criteria were enrolled. Visual analysis showed that, compared with the control group, the AD group showed mostly bilateral symmetrical hypometabolism in temporoparietal lobes, with the most significant hypometabolism in the medial temporal lobe and posterior cingulate gyrus; the CAA group exhibited unspecific cortical hypometabolic areas corresponding to hemorrhage. Quantitative analysis of voxel-based brain metabolism images showed that metabolism in the posterior cingulate gyrus, parahippocampal gyrus, parietal lobe, and medial temporal lobe was significantly reduced in the AD group compared with the control group (P < 0.01); metabolism was significantly reduced in the extensive white matter areas, as well as in the caudate nucleus head, corpus callosum, anterior cingulate gyrus, and lateral temporal cortex in the CAA group (P < 0.01). Quantitative analysis based on brain regions showed that the standardized uptake value ratio (SUVr) of 18F-FDG in the occipital/posterior cingulate (O/PC) was significantly lower in the CAA group than in the AD group (0.91±0.05 vs. 1.07±0.08, P < 0.001); the area under the curve for O/PC SUVr identification of probable CAA and AD was 0.98 (95% CI: 0.93-1.00), with an optimal threshold of 0.96, exhibiting sensitivity of 100% and specificity of 90%. Conclusions Probable CAA and AD patients exhibited distinct brain hypometabolism patterns. O/PC SUVr can be a sensitive indicator for differential diagnosis between CAA and AD.
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