A Longitudinal Study of Collateral Flow Patterns in the Circle of Willis and the Ophthalmic Artery in Patients With a Symptomatic Internal Carotid Artery Occlusion
Bibliographic record
Abstract
BACKGROUND AND PURPOSE: The purpose of the present study was to assess whether the direction of flow via the circle of Willis and the ophthalmic artery (OphA) changed over time in patients with a symptomatic occlusion of the internal carotid artery (ICA) who did not experience recurrent cerebral ischemic symptoms. METHODS: Sixty-two patients with a symptomatic ICA occlusion were investigated within 6 months after symptoms occurred. The investigations were repeated after 6 and 12 months. The directions of flow in the A1 segment and the posterior communicating artery (PCoA), both on the side of the symptomatic ICA occlusion, were assessed with the use of magnetic resonance angiography. The pattern of collateral flow via the circle of Willis was categorized as via the A1 segment only, via the PCoA only, via the A1 segment plus the PCoA, or no collateral flow via the circle of Willis. The direction of flow in the OphA was investigated with transcranial Doppler sonography. CO(2) reactivity was determined with transcranial Doppler sonography to investigate whether changes in flow patterns were accompanied by changes in cerebrovascular reactivity. RESULTS: There were no statistically significant changes over time in the direction of blood flow in the A1 segment and the PCoA or in the pattern of collateral flow via the circle of Willis. On average, 72% of patients with a unilateral ICA occlusion (n=41) had willisian collateral flow compared with 37% of patients with a bilateral ICA occlusion (n=21; P<0.05). Patients with a unilateral ICA occlusion tended to a lower prevalence of reversed flow via the OphA over time. CO(2) reactivity did not change significantly in any patient group. In patients with a unilateral ICA occlusion, decreased CO(2) reactivity was associated with a higher prevalence of absent willisian collateral flow and a lower prevalence of collateral flow via the A1 segment plus the PCoA. CONCLUSIONS: The absence of recurrent cerebral ischemic symptoms in patients with a symptomatic ICA occlusion is not associated with an improvement in collateral flow via the circle of Willis or the OphA during 1.5-year follow-up.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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 teacher head, 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".