Abstract | OBJECTIVE: DESIGN: Twelve trained raters unaware of clinical and autopsy information independently reviewed FDG-PET scans and provided their diagnostic impression and confidence of either FTLD or AD. Six of these raters also recorded whether metabolism appeared normal or abnormal in 5 predefined brain regions in each hemisphere-frontal cortex, anterior cingulate cortex, anterior temporal cortex, temporoparietal cortex, and posterior cingulate cortex. Results were compared with neuropathological diagnoses. SETTING: Academic medical centers. PATIENTS: Forty-five patients with pathologically confirmed FTLD (n=14) or AD (n=31). RESULTS: Raters had a high degree of diagnostic accuracy in the interpretation of FDG-PET scans; however, raters consistently found some scans more difficult to interpret than others. Unanimity of diagnosis among the raters was more frequent in patients with AD (27 of 31 patients [87%]) than in patients with FTLD (7 of 14 patients [50%]) (P=.02). Disagreements in interpretation of scans in patients with FTLD largely occurred when there was temporoparietal hypometabolism, which was present in 7 of the 14 FTLD scans and 6 of the 7 scans lacking unanimity. Hypometabolism of anterior cingulate and anterior temporal regions had higher specificities and positive likelihood ratios for FTLD than temporoparietal hypometabolism had for AD. CONCLUSIONS: Temporoparietal hypometabolism in FTLD is common and may cause inaccurate interpretation of FDG-PET scans. An interpretation paradigm that focuses on the absence of hypometabolism in regions typically affected in AD before considering FTLD is likely to misclassify a significant portion of FTLD scans. Anterior cingulate and/or anterior temporal hypometabolism indicates a high likelihood of FTLD, even when temporoparietal hypometabolism is present. Ultimately, the accurate interpretation of FDG-PET scans in patients with dementia cannot rest on the presence or absence of a single region of hypometabolism but rather must take into account the relative hypometabolism of all brain regions.
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Authors | Kyle B Womack, Ramon Diaz-Arrastia, Howard J Aizenstein, Steven E Arnold, Nancy R Barbas, Bradley F Boeve, Christopher M Clark, Charles S DeCarli, William J Jagust, James B Leverenz, Elaine R Peskind, R Scott Turner, Edward Y Zamrini, Judith L Heidebrink, James R Burke, Steven T DeKosky, Martin R Farlow, Matthew J Gabel, Roger Higdon, Claudia H Kawas, Robert A Koeppe, Anne M Lipton, Norman L Foster |
Journal | Archives of neurology
(Arch Neurol)
Vol. 68
Issue 3
Pg. 329-37
(Mar 2011)
ISSN: 1538-3687 [Electronic] United States |
PMID | 21059987
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- Radiopharmaceuticals
- Fluorodeoxyglucose F18
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Topics |
- Adult
- Age of Onset
- Aged
- Alzheimer Disease
(diagnostic imaging, metabolism, pathology)
- Brain
(pathology)
- Diagnosis, Differential
- Diagnostic Errors
- Female
- Fluorodeoxyglucose F18
- Frontotemporal Lobar Degeneration
(diagnostic imaging, metabolism, pathology)
- Humans
- Image Processing, Computer-Assisted
- Male
- Middle Aged
- Neuropsychological Tests
- Observer Variation
- Parietal Lobe
(diagnostic imaging, metabolism, pathology)
- Positron-Emission Tomography
- Radiopharmaceuticals
- Reproducibility of Results
- Temporal Lobe
(diagnostic imaging, metabolism, pathology)
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