Evaluation of a Calibrated ¹⁸F-FDG PET Score as a Biomarker for Progression in Alzheimer Disease and Mild Cognitive Impairment

Visual-Statistical Interpretation of 18F-FDG-PET Images for Characteristic Alzheimer Patterns in a Multicenter Study: Inter-Rater Concordance and Relationship to Automated Quantitative Evaluation

“…This correlation may have been something expected from reports on similar/automated analysis. 5,6 However, this association was observed in a large-scale multicenter study by using various camera models on a wide spectrum of subjects in the present study. From the standpoint of detecting the AD pattern, cases evaluated as having positive AD findings by complete agreement of all 3 raters tended to show a higher quantitative index than the cases that fewer than 3 raters interpreted as having positive AD findings.…”

“…Although a recently developed anatomic standardization technique can define ROIs automatically and further allows voxelwise statistical analysis to generate Z-maps, standardization may not always be accurate and may require adjustment by a human observer. Although these region-of-interest values can be processed into a numeric indicator such as an FDG-PET score 4,5 and a cutoff level can be determined, a single indicator may not be as accurate as complex and comprehensive evaluation by expert readers. As a result, a "combined" approach of visual and quantitative evaluation is often used during image interpretation, in which the readers examine both the tomographic PET images and the result of region-ofinterest analysis and/or a Z-map.…”

“…The raters looked at the 3D stereotactic surface projection Z-map of 18 F-FDG-PET visually as well as the 18 F-FDG tomographic images because it is considered the standard means of human interpretation of 18 F-FDG-PET images in Japan and therefore was adopted as the official interpretation method in J-ADNI. Images were also assessed by automated quantitative analysis by using an FDG-PET score, which was derived from ADtsum, 4,5 and were compared with the visual-statistical rating by the 3 raters and with their consensus.…”

A Cochrane review on brain [18F]FDG PET in dementia: limitations and future perspectives

“…From a methodological point of view, both studies with qualitative and those with semiquantitive analyses of [ 18 F]FDG PET scans were included in the Cochrane review. Sensitivity analysis, however, was performed only in 14 studies (150 subjects) as three studies included patients from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort and only the largest one of these studies was included in the analysis [13]. In contrast, no threshold concerning the number of subjects included in a study was set and actually 6 out of 16 of the studies included had fewer than 30 subjects.…”

Tau PET and tauopathies

“…Intraclass correlation coefficients (ICC) are excellent (0.9 or better) for most brain regions. Another potential imaging biomarker to assess disease progression is FDG PET, for which a comparable ICC of 0.92 has been reported [4]. However, that was a composite score as opposed to being derived from regional values, which tend to be less reproducible.…”