Abstract W P35: Assessment of Collaterals on Day-2 CT Angiography Can Predict Functional Outcome in Thrombolyzed Anterior Circulation Acute Ischemic Stroke
Bibliographic record
Abstract
Background: Several methods exist that assess the intracranial collaterals on CT-angiography (CTA) of the brain. We compared existing methods for quantification of collaterals on day-2 CTA in thrombolyzed AIS patients to assess their predictive value for functional outcome. Methods: Consecutive AIS patients treated with intravenous tissue plasminogen activator (IV-tPA) during 2007-2012 were included. Data were collected for demographics, vascular risk factors, NIHSS scores and stroke subtypes. Intracranial collaterals were evaluated by 2 independent neuroradiologists using 4 existing methods- Miteff’s system (grades middle cerebral artery (MCA) collateral branches with respect to sylvian fissure); Maas system (compares collaterals in affected hemisphere against the contralateral side); Modified Tan’s scale (collaterals in 50% or more of MCA territory classified as good); and 20-point collateral grading scale by Alberta Stroke Program Early CT score (ASPECTS) methodology. Good functional outcome at 3-months was determined by modified Rankin scale (mRS) scores of 0-1. Results: Day-2 CTA was performed in 150 patients with anterior circulation AIS treated with IV-tPA. Median age 66yrs (range 33-92), 47% males, median NIHSS 19 points (range 4-34) and median onset-to-treatment time 165 minutes (range 74-274). Overall, 67 (44.6%) patients achieved good functional outcome at 3-months. On univariable analysis- younger age, lower pre-tPA NIHSS scores, atrial fibrillation, good collaterals according to ASPECTS scoring and good collaterals by Maas methodology were significantly associated with good functional outcome. On multivariable analysis, lower NIHSS (OR 1.155 per NIHSS point; 95% CI 1.066-1.251, p=0.001), younger age (OR 1.052 per year; 95% CI 1.012-1.094, p=0.010), good collaterals by Maas methodology (OR 2.805 95% CI 1.122 -7.011, p =0.002) and good collaterals (score of 9 or more) by ASPECTS methodology (OR 3.769 ; 95%CI: 1.327- 10.708, p= 0.013 ) were found as independent predictors of good outcome. Conclusion: Of the existing intracranial collaterals scoring systems, only the ASPECTS and Maas methods are reliable predictor of favourable outcome in thrombolyzed anterior circulation AIS patients.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 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) | 0.002 | 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".