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Distinguishing Parkinsonian Disorders and Cognitive Disorder Subtypes Using Pseudocontinuous Arterial Spin Labeling
Belnavis A, Chen K, Chiu S, Ofori E.. Preprints.org, 2026-09-16
Topic: Plasma and spinal-fluid biomarkers
Arterial spin labelling (ASL) MRI provides a noninvasive measure of cerebral perfusion, raising the possibility of distinguishing Parkinson's disease (PD) from atypical parkinsonian syndromes (corticobasal syndrome, multiple system atrophy, progressive supranuclear palsy) and of separating the associated cognitive disorders, PD dementia and dementia with Lewy bodies (DLB), from Alzheimer's disease (AD). Whether perfusion can make either distinction in an individual patient has not been established. We conducted a scoping review reported in accordance with PRISMA-ScR, searching PubMed to 17 July 2026 (968 records, 33 studies included), and mapped the cohort-level diagnostic evidence available for each contrast. The review was restricted to pseudo-continuous ASL (pCASL), the consensus-recommended implementation for clinical use. For every study we charted acquisition parameters (post-labelling delay scheme, field strength), processing pipelines, the perfusion measures reported (absolute and normalised cerebral blood flow, arterial transit time), and any diagnostic accuracy metric, recording absence of reporting as such, and assessed risk of bias and applicability against criteria tailored to the review question. Four thresholds for single-patient use were fixed in writing before any study was counted, then applied descriptively rather than as eligibility criteria. Direct comparison against atypical parkinsonian syndromes was near-absent: one study addressed corticobasal syndrome (median AUC 0.787 across regions), none addressed multiple system atrophy or progressive supranuclear palsy, and PSP patients appeared only within a pooled parkinsonism-plus group. Evidence on the cognitive contrasts was more substantial, with DLB separating from AD at both the dementia and prodromal stages, reaching an arterial transit time AUC of 0.861. No study reported external validation in an independent cohort, and no contrast met the prespecified thresholds. Answering the question requires cohorts recruited consecutively from patients in whom the diagnosis is genuinely uncertain, multi-delay acquisition, thresholds specified in advance, and validation outside the derivation cohort, with PD against PSP and PD against corticobasal syndrome the highest priority.
Key findings
- Four thresholds for single-patient use were fixed in writing before any study was counted, then applied descriptively rather than as eligibility criteria.
- Direct comparison against atypical parkinsonian syndromes was near-absent: one study addressed corticobasal syndrome (median AUC 0.787 across regions), none addressed multiple system atrophy or progressive supranuclear palsy, and PSP patients appeared only within a pooled parkinsonism-plus group.
- Evidence on the cognitive contrasts was more substantial, with DLB separating from AD at both the dementia and prodromal stages, reaching an arterial transit time AUC of 0.861.
- No study reported external validation in an independent cohort, and no contrast met the prespecified thresholds.
- Answering the question requires cohorts recruited consecutively from patients in whom the diagnosis is genuinely uncertain, multi-delay acquisition, thresholds specified in advance, and validation outside the derivation cohort, with PD against PSP and PD against corticobasal syndrome the highest priority.
Study details
- Effect sizeAUC 0.787
- Evidence strengthModerate
How this study scored 16/100
Preprint — not yet peer-reviewed. It scored 29 on the same rubric, but non-peer-reviewed sources are capped at 16, so it shows as 16. Scored zero for study design, sample size, studied in people and randomised / blinded because the record does not state it. We have no data on times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 18 of the 62 points we could judge it on, which is 29 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 2 / 10 | Tier 4 — not a peer-reviewed journal (Preprints.org) |
| Journal's citation record | 0 / 4 | Not a journal article, so the journal's record does not count |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 4 / 10 | Preprint — not yet peer-reviewed. Hosted on a preprint server. |
| How recent | 5 / 5 | 2026 — within 1 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 | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| 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 | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 1 / 2 | Not in PubMed, but has a DOI |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 18 / 62 | Scored on 12 of 20 parts. We have no data for the rest, so they are left out: 18 of the 62 points we could judge it on is 29 out of 100. |
| Total | 29 / 100 | Capped to 16 because this is not a peer-reviewed article. |
What each of these 20 components measures, and what this score is not →
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Belnavis, A., Chen, K., Chiu, S., & Ofori, E. (2026). Distinguishing Parkinsonian Disorders and Cognitive Disorder Subtypes Using Pseudocontinuous Arterial Spin Labeling. Preprints.org. https://doi.org/10.20944/preprints202609.1308.v1
Vancouver
Belnavis A, Chen K, Chiu S, Ofori E. Distinguishing Parkinsonian Disorders and Cognitive Disorder Subtypes Using Pseudocontinuous Arterial Spin Labeling. Preprints.org. 2026. doi:10.20944/preprints202609.1308.v1.
BibTeX
@article{belnavis2026-c4b9a721,
author = {Belnavis, A. and Chen, K. and Chiu, S. and Ofori, E.},
title = {{Distinguishing Parkinsonian Disorders and Cognitive Disorder Subtypes Using Pseudocontinuous Arterial Spin Labeling}},
journal = {Preprints.org},
year = {2026},
doi = {10.20944/preprints202609.1308.v1},
url = {https://doi.org/10.20944/preprints202609.1308.v1}
}
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