P3‐389: ELEVATED CEREBRAL ARTERIAL PULSATILITY AND RESISTIVITY ARE ASSOCIATED WITH COGNITIVE IMPAIRMENT: A PHASE‐CONTRAST MRI STUDY
Bibliographic record
Abstract
Emerging evidence suggests cerebrovascular dysfunctions play an important role in the pathogenesis of Alzheimer's disease. Elevated arterial pulsation due to arterial stiffness can cause cerebral microvascular and brain tissue damage, which may contribute to cognitive impairment. The association of arterial pulsatility and cognitive dysfunction has previously been studied using transcranial doppler (TCD) sonography However, the efficient application of TCD depends on the availability of an acoustic windows which is known to be limited in older subjects. The goal of this study was to assess the utility of phase contrast MRI (PC-MRI) in quantifying cerebral arterial pulsatility in the presence of mild cognitive impairment (MCI). volunteers from the Los Angeles Latino Eye Study cohort were included in this study and underwent MRI scans (Table 1). Cognitive assessment was performed using the global clinical dementia rating (CDR) and the Montreal cognitive assessment (MoCA) Test. Flow waveform over a cardiac cycle was measured at the internal carotid artery (ICA) using an ECG-triggered single-slice PC-MRI (Figure 1). Mean blood flow rate (Qmean), pulsatility index (PI=(Qmax - Qmin)/Qmean), and resistivity index (RI=(Qmax - Qmin)/Qmax) were calculated, where PI and RI both reflect the resistance in microvasculature fed by the ICA. Furthermore, PI is inversely related to vascular compliance which acts to buffer the systolic pressure during perfusion. Non-parametric statistical analyses (Wilcoxon signed-rank and Spearman's rank correlation) were performed to assess the association of flow parameters with cognitive performance. Compared to the subjects with normal cognition (n=25), subjects with MCI (n=16) had significantly higher RI (0.69±0.08 vs 0.76±0.08, p=0.03, Figure 2). Increased PI was observed in MCI (1.22±0.31 vs 1.39±0.35, p=0.08). RI and PI were both significantly increased with the decrease in MoCA score (p=0.02 and 0.05, respectively, Figure 3). No significant correlation was found between Qmean and cognitive performance.
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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) | 0.003 | 0.001 |
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".