Brain Microvasculature Involvement in ANCA Positive Vasculitis
Bibliographic record
Abstract
OBJECTIVE: Endothelial dysfunction is associated with arterial stiffness, a factor that is increasingly recognised as an important determinant of cardiovascular risk. High-flow organs such as the brain and kidneys are particularly sensitive to excessive pressure and flow pulsatility. High, local blood flow is associated with low microvascular impedance, which facilitates the penetration of excessive pulsatile energy into the microvascular bed leading to tissue damage. Systemic endothelial dysfunction and arterial stiffness have been demonstrated in peripheral vessels in associated vasculitis (AAV). Although, the brain involvement is not infrequent in AAV, it has not been evaluated previously. Our aim is to evaluate the involvement of the brain microvasculature in AAV. METHODS: Twenty-three patients with inactive AAV were studied. Brain blood flow was assessed by transcranial Doppler (TCD) and single-photon positron emission tomography (SPECT), structural brain involvement by brain MRI and cognitive scores by Montreal Cognitive Assessment (MoCA) test. RESULTS: Lower mean flow velocity (MFV) was associated to altered SPECT perfusion, higher white matter changes (WMC), lower MoCA scores and younger age (p < 0.05). Middle cerebral artery pulsatility index (MCA-PI) was related to hypertension, diabetes, lower scores on MoCA, increased vasculitis damage index (VDI) and perfusion impairment in SPECT (p < 0.05). These data were reproduced for all intracranial arteries. Up to 88.9% of patients had WMC on MRI. A higher lesion load was associated with age, decreased MoCA and fewer MFV with higher PI. The multivariable linear regression analysis showed that the greater the lesion loads, greater the bifrontal atrophy, MCA-PI and lower MoCA scores. Up to 60.9% of patients presented a decreased MoCA score (p = 0.012). It appeared to be related to VDI (p = 0.04), WMC (p = 0.004) and altered SPECT (p = 0.05). CONCLUSIONS: The alterations in brain perfusion SPECT, the presence of white matter lesions on MRI, as well as increased PI and RI with lower MFV of the cerebral vessels in TCD suggest the presence of microangiopathy in asymptomatic AAV that could lead to cognitive impairment.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".