E-056 Anatomical findings at the circle of willis and cervical carotid arteries during large vessel occlusion stroke: Observations from computed tomography angiography
Bibliographic record
Abstract
Objective The circle of Willis (CoW) and cervical carotid arteries are potentially important sources of collateral flow (or flow limitation) during acute large vessel occlusion (LVO) in the anterior circulation. We sought to examine the anatomical components of the circle and the cervical carotid arteries to determine whether they bear any relationship to acute stroke severity. Methods Consecutive patients with acute LVO who underwent endovascular thrombectomy (EVT) between September 2018 and June 2019 were assessed using computed tomography angiography (CTA). Measurements were made of the luminal diameters of 16 anatomical vascular components of the CoW and neck. Measures of stroke severity, including the admission NIHSS, ASPECTS and mCTA collateral scores, were statistically analyzed for any relationship to vascular measurements. Results One hundred patients (51 men, 49 women) between 32 and 99 years of age (mean 72.3 years) were studied. No relationship was found between the anterior or posterior collateral Willis pathways and measures of stroke severity. On the other hand, the ophthalmic arteries did exhibit a relationship to stroke severity. In adjusted analysis, a 1-mm increase in the ipsilateral and contralateral ophthalmic artery diameter was independently associated with a 4.80-point decrease (95% CI: 1.26, 8.34) and a 6.31-point increase (95% CI: 0.27, 12.36) in the NIHSS scale, respectively. Similarly, 1-mm increases in the ipsilateral and contralateral ophthalmic artery diameter were respectively associated with a 1.53-point increase (95% CI: 0.66, 2.41) and a 2.62-point decrease (95% CI 1.12, 4.13) in the ASPECTS. In the neck, ipsilateral carotid artery analysis showed a majority with 0% stenosis, and unexpectedly no NASCET stenosis between 55% and 95%, while a minority (14%) were 95% to 100%. Conclusions Stroke severity and native collateral during LVO is unrelated to circle of Willis anatomy. Ophthalmic artery calibers show some relationship to stroke severity. Our findings also support the notion of acute progression of moderate and severe NASCET stenoses to near occlusion or complete occlusion at the onset of LVO stroke, such that no cases exhibited moderate or severe 55-95% narrowing. Disclosures R. Kiwan: None. S. Lownie: None.
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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 | 0.003 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".