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An evidence based algorithm for the utility of FDG-PET for diagnosing Alzheimer’s disease according to presence of medial temporal lobe atrophy

Lookup NU author(s): Dr Michael FirbankORCiD, Dr James LloydORCiD, Professor David Williams, Dr Robert Barber, Dr Sean Colloby, Nicola Barnett, Kirsty OlsenORCiD, Dr Christopher Davison, Professor Cam Donaldson, Professor John O'Brien



This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).


Background Imaging biomarkers for Alzheimer’s disease include medial temporal lobe atrophy (MTLA) depicted on CT or MRI, and patterns of reduced metabolism on FDG-PET. Aims To investigate whether MTLA on head CT predicts the diagnostic usefulness of an additional FDG-PET scan. Methods Participants had a clinical diagnosis of Alzheimer’s disease (AD; n=37), dementia with Lewy bodies (DLB; n=30), or were similarly aged controls (n=30). We visually rated MTLA on coronally reconstructed CT scans and, separately and blind to CT ratings, abnormal appearances on FDG-PET scans. Results Using a pre-defined cutoff of MTLA >=5 on the Scheltens (0-8) scale, 0/30 controls, 6/30 DLB and 23/30 AD had marked MTLA. FDG-PET performed well for diagnosing AD vs DLB in the low MTLA group (sensitivity / specificity of 71%/79%), but in the high MTLA subjects, diagnostic performance of FDG-PET was not better than chance. Conclusions In the presence of a high degree of MTLA, the most likely diagnosis is AD, and an FDG-PET scan will probably not provide significant diagnostic information. However, in cases without MTL atrophy, if the diagnosis is unclear, an FDG-PET scan may provide additional clinically useful diagnostic information.

Publication metadata

Author(s): Firbank MJ, Lloyd JJ, Williams ED, Barber R, Colloby SJ, Barnett NA, Olsen K, Davison C, Donaldson C, Herholz K, O'Brien JT

Publication type: Article

Publication status: Published

Journal: British Journal of Psychiatry

Year: 2016

Volume: 208

Issue: 5

Pages: 491-496

Online publication date: 04/06/2015

Acceptance date: 07/12/2014

Date deposited: 07/01/2016

ISSN (print): 0007-1250

ISSN (electronic): 1472-1465

Publisher: Royal College of Psychiatrists


DOI: 10.1192/bjp.bp.114.160804

PubMed id: 26045347


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