Association between glymphatic function and cerebrovascular reactivity in patients with cerebral amyloid angiopathy and Alzheimer's disease
Bibliographic record
Abstract
Abstract Background Cerebral amyloid angiopathy (CAA) is characterized by deposition of amyloid‐beta (Aβ) within the walls of the small blood vessels of the brain and leptomeninges. It causes ∼20% of intracerebral hemorrhage, increases the risk of dementia, and is common in patients with Alzheimer's disease (AD). Deposition of Aβ may result from impaired glymphatic clearance concurrent with a reduction in cerebrovascular reactivity, but this has not been investigated in patients with CAA or AD. Method Patients with CAA ( N = 43) and AD ( N = 16) patients and healthy controls (HC; N = 53) underwent an MRI at 3T that included a T1‐weighted and fluid attenuated inversion recovery (FLAIR) images, diffusion‐weighted imaging (30 directions; b‐value=1000s/mm 2 ) and BOLD imaging involving a 2‐minute hypercapnic challenge (5% inspired CO 2 ). Glymphatic function was quantified by diffusion tensor imaging along the perivascular space (DTI‐ALPS; ratio between diffusion in the perivascular space direction and diffusion of free water in the interstitium) while CVR was quantified as the % change in BOLD per mmHg increase in the end‐tidal partial pressure of CO 2 . Group comparisons of DTI‐ALPS were adjusted for age and sex while comparisons of CVR were adjusted for age, sex and hypertension. Associations between DTI‐ALPS and CVR were adjusted for age, sex, hypertension, white matter hyperintensity volume and group. Result CAA and AD participants were predominantly male whereas HCs were predominantly female (Table). CAA participants were older with a greater prevalence of hypertension. DTI‐ALPS was lower in patients with CAA and AD versus HCs (ANCOVA, p <0.001; Figure 1A). Similarly, grey matter (GM), white matter (WM), and global CVR (mean of GM and WM) were lower in CAA and AD compared to HCs (all ANCOVAs, p <0.001; Figure 1B). However, DTI‐ALPS was not associated with GM (‐0.18 (‐0.73 ‐ 0.36), p = 0.504), WM (0.02, ‐0.84 ‐ 0.89, p = 0.646) or global CVR (‐0.15, ‐0.85 ‐ 0.55, p = 0.94; Figure 2). Conclusion Vascular contributions to reduced glymphatic function in CAA and AD may be more related to changes in vasomotion and pulsatility of blood flow through cerebral vessels than the ability of the cerebrovasculature to dilate.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".