Abstract 154: Non-Contrast Computed Tomography Based Patient Selection Achieves Similar Outcomes to Advanced Neuroimaging in Late Time Window Endovascular Thrombectomy
Bibliographic record
Abstract
Background and Aims: Endovascular Thrombectomy (EVT) for anterior circulation large vessel occlusion(LVO) in late time windows (over 6 hours) has been validated. Studies utilised advanced neuroimaging to select patients with small ischaemic cores. We have evaluated if routine imaging with non-contrast CT (NCCT) is inferior to CT Perfusion (CTP) to select patients for EVT in late time windows. Method: A prospectively maintained database of all EVT patients at two tertiary referral centres was retrospectively interrogated to identify anterior circulation LVO patients, with groin puncture times over 6 hours from symptom onset or time last seen well. Subjects were divided into those that underwent CTP in addition to routine NCCT and CT angiography (CTA) and those that were selected by NCCT/CTA alone. Results: A total of 85 patients were included, 39 (46%) had CTP (CTP+). No significant difference between baseline characteristics of CTP+ vs CTP- groups such as age (mean 66 vs 74, p=0.26), gender (male 49% vs 59%, p=0.36), median ASPECT (8 vs 8, p=0.84) and median NIHSS (13 vs 13, p=0.42) were observed. The two groups were also well matched with respect to time metrics including onset to imaging time (mean 519 vs 477 mins, p=0.41), time to groin puncture (mean 733 vs 690 mins, p=0.90) and procedure time (mean 41 vs 38 mins, p=0.94). No significant difference between early neurological recovery (36% vs 44%, p=0.48), 90 day mean utility weighted mRS (6.2, 95% CI [5.1, 7.4] vs 6.4, 95% CI [5.2, 7.5] p=0.75), rates of functional independence at 90 days (60% vs 64%, p=0.76), and rates of symptomatic haemorrhage (8 vs 9%, p=0.41) was observed between the groups. Conclusion: In late time windows, anterior circulation LVO patients selected for EVT based on routine imaging had non-inferior outcomes to those who underwent CTP. Our data suggests that late time window patients who do not have access to advanced neuroimaging should not be excluded from EVT.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".