Home › Research › Biomarkers
Spatial extent as a sensitive amyloid-PET metric in preclinical Alzheimer's disease
Farrell ME, Thibault EG, Becker JA, Price JC, Healy BC, Hanseeuw BJ, Buckley RF, Jacobs HIL et al.. Alzheimer's & dementia : the journal of the Alzheimer's Association, 2024-07-10
Topic: Amyloid, tau and blood-test diagnosis
Introduction Spatial extent-based measures of how far amyloid beta (Aβ) has spread throughout the neocortex may be more sensitive than traditional Aβ-positron emission tomography (PET) measures of Aβ level for detecting early Aβ deposits in preclinical Alzheimer's disease (AD) and improve understanding of Aβ's association with tau proliferation and cognitive decline. Methods Pittsburgh Compound-B (PIB)-PET scans from 261 cognitively unimpaired older adults from the Harvard Aging Brain Study were used to measure Aβ level (LVL; neocortical PIB DVR) and spatial extent (EXT), calculated as the proportion of the neocortex that is PIB+. Results EXT enabled earlier detection of Aβ deposits longitudinally confirmed to reach a traditional LVL-based threshold for Aβ+ within 5 years. EXT improved prediction of cognitive decline (Preclinical Alzheimer Cognitive Composite) and tau proliferation (flortaucipir-PET) over LVL. Discussion These findings indicate EXT may be more sensitive to Aβ's role in preclinical AD than level and improve targeting of individuals for AD prevention trials. Highlights Aβ spatial extent (EXT) was measured as the percentage of the neocortex with elevated Pittsburgh Compound-B. Aβ EXT improved detection of Aβ below traditional PET thresholds. Early regional Aβ deposits were spatially heterogeneous. Cognition and tau were more closely tied to Aβ EXT than Aβ level. Neocortical tau onset aligned with reaching widespread neocortical Aβ.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Farrell, M. E., Thibault, E. G., Becker, J. A., Price, J. C., Healy, B. C., Hanseeuw, B. J., et al. (2024). Spatial extent as a sensitive amyloid-PET metric in preclinical Alzheimer's disease. Alzheimer's & dementia : the journal of the Alzheimer's Association. https://doi.org/10.1002/alz.14036
Vancouver
Farrell ME, Thibault EG, Becker JA, Price JC, Healy BC, Hanseeuw BJ, et al. Spatial extent as a sensitive amyloid-PET metric in preclinical Alzheimer's disease. Alzheimer's & dementia : the journal of the Alzheimer's Association. 2024. doi:10.1002/alz.14036. PMID: 38988055.
BibTeX
@article{farrell2024-38988055,
author = {Farrell, M. E. and Thibault, E. G. and Becker, J. A. and Price, J. C. and Healy, B. C. and Hanseeuw, B. J. and Buckley, R. F. and Jacobs, H. I. L. and others},
title = {{Spatial extent as a sensitive amyloid-PET metric in preclinical Alzheimer's disease}},
journal = {Alzheimer's \& dementia : the journal of the Alzheimer's Association},
year = {2024},
doi = {10.1002/alz.14036},
pmid = {38988055},
url = {https://doi.org/10.1002/alz.14036}
}
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
Key findings
- Results EXT enabled earlier detection of Aβ deposits longitudinally confirmed to reach a traditional LVL-based threshold for Aβ+ within 5 years.
- Discussion These findings indicate EXT may be more sensitive to Aβ's role in preclinical AD than level and improve targeting of individuals for AD prevention trials.
Why it matters
Measuring how far amyloid has spread across the neocortex detected early amyloid deposits better than measuring amyloid level and improved prediction of cognitive decline and tau spread. This is about improving early detection and trial targeting, not about treating, curing, or preventing Alzheimer's disease.
New to this subject? Start with our plain-English guide: Blood tests & biomarkers →
Study details
- Evidence strengthLow
Limitations
The comparison cohort was 261 cognitively normal older adults from a single study (the Harvard Aging Brain Study), so it's not yet known how well this new measure performs in other, more diverse populations.
How this study scored 48/100
Published in a leading specialty journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Alzheimer's & dementia : the journal of the Alzheimer's Association) |
| Journal's citation record | 2 / 4 | Alzheimer s & Dementia: journal h-index 228 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2024 — within 3 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 2 / 7 | Cited 12 times (OpenAlex, 2026-10-10) |
| Citations per year | 2 / 5 | 3.0 citations a year over 4 year(s) since 2024 |
| Impact for its field and year | 3 / 6 | Cited 3.3× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 1 / 6 | Cited by 2 other studies in this library |
| Still being cited | 1 / 4 | Cited 12 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Keith A. Johnson: h-index 127 (OpenAlex, whole career) |
| Institution's track record | 3 / 3 | Harvard University: institution h-index 3,235 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 6 institution(s) in 3 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 38988055) |
| Free to read | 2 / 2 | Free to read |
| Total | 48 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Studies this one cites
Referenced by this study and also in the alzhub library, so you can read them here. Showing 12 of 26.
Later studies that cite this one
2 studies in the alzhub library list this one in their references.
Related studies in Biomarkers
Also tagged “classification”
835 studies in the library carry the topic tag “classification”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 835 tagged studies.