Highlight
- Quantitative infarct volumetry outperforms ASPECTS in predicting functional outcomes after thrombectomy in large-core stroke.
- Patients classified as large core by ASPECTS alone may not have poor prognosis if volumetry shows smaller infarct volume.
- A therapeutic ceiling at an infarct volume ≥110 mL was identified beyond which thrombectomy benefit diminishes.
- Integrating volumetric thresholds can refine patient selection and minimize futile thrombectomy procedures.
Study Background
Endovascular thrombectomy has revolutionized acute ischemic stroke management, especially in patients with large vessel occlusion. However, optimal patient selection remains a challenge, particularly for patients presenting with large-core infarctions. Traditionally, the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) — a region-based topographical scoring system on non-contrast CT — has served as a practical tool to estimate infarct extent and guide eligibility. Despite its utility, ASPECTS is limited by inter-rater variability and coarse spatial assessment and may not capture the therapeutic ceiling where reperfusion benefits wane in very large infarcts.
Understanding the clinical thresholds beyond which reperfusion intervention offers negligible benefit is critical. This study by Kim et al. (2026) investigates whether volumetric infarct assessment via diffusion-weighted imaging (DWI), CT perfusion (CTP), and non-contrast CT can better define prognostic and therapeutic boundaries than ASPECTS alone.
Study Design
This investigation utilized a nationwide, multicenter registry in Korea from 2022 to 2024 including 552 patients treated with thrombectomy for large vessel occlusion strokes. The cohort had a mean age of 70.4 years, with 57.8% males. The study focused on large-core strokes as defined by ASPECTS and volumetric thresholds from imaging modalities — DWI, CTP, and non-contrast CT. Key comparisons were made between patients with discordant ASPECTS and volumetric large-core classifications.
The primary outcome was poor functional outcome, defined as a modified Rankin Scale (mRS) score of 5 to 6 at 90 days. Additionally, ordinal mRS shift analyses and target trial emulations were conducted to estimate thrombectomy treatment effects across different infarct volume strata, delineating potential therapeutic benefit or futility.
Key Findings
Discordance between ASPECTS and volumetric measurements was notable. Patients categorized as large core by ASPECTS but with smaller infarct volumes on DWI (ASPECTS-only large core) demonstrated poor functional outcome rates comparable to those with small cores by both criteria (11.8% vs 11.7%), and no excess adjusted risk, suggesting ASPECTS alone may overestimate infarct burden in some cases.
In contrast, volumetric confirmation of large core status across DWI, CTP, and non-contrast CT consistently predicted significantly worse outcomes regardless of ASPECTS scores. For example, the DWI-only large-core group exhibited an adjusted odds ratio of 6.92 (95% CI, 2.58–19.34) for poor outcome, underscoring the superior prognostic accuracy of volumetry.
The target trial emulations demonstrated an overall attenuation of thrombectomy benefit in the cohort with large cores (common odds ratio, 0.56; 95% CI, 0.31–1.03). Stratified analyses identified a therapeutic ceiling: infarct volumes between 50 to 110 mL retained significant benefit from thrombectomy (common odds ratio, 0.38; 95% CI, 0.15–0.97), while volumes exceeding 110 mL showed no meaningful benefit, implying diminishing returns and potential futility in extensive infarctions.
Expert Commentary
This study provides compelling evidence that volumetric infarct assessment supersedes ASPECTS in defining the upper threshold where endovascular thrombectomy confers benefit. Prior reliance on ASPECTS, while pragmatic, may lead to inclusion of patients unlikely to gain from reperfusion based on infarct size alone, exposing them to procedural risks without meaningful recovery prospects.
These findings align with emerging guidelines advocating for more sophisticated imaging selection, incorporating core volume thresholds in addition to time and vessel status. The identification of a volumetric therapeutic ceiling at ~110 mL provides a clear, actionable cutoff to optimize patient selection. However, caution is warranted given variability in individual patient physiology, collaterals, and infarct evolution kinetics. Moreover, generalizability beyond the Korean population and imaging techniques requires validation.
In clinical practice, volumetric assessment via automated imaging software could enhance decision-making but also necessitates rapid, standardized protocols to be feasible in hyperacute care settings.
Conclusion
This comprehensive multicenter study elucidates the limitations of ASPECTS as a sole criterion in large-core stroke thrombectomy candidacy and highlights the prognostic and predictive superiority of quantitative infarct volumetry. The delineation of a therapeutic volume ceiling at ≥110 mL informs risk-benefit assessments, aiming to reduce futile reperfusion interventions.
Integrating volumetric thresholds into clinical algorithms represents a critical advance toward individualized stroke care, promoting safety and outcome optimization. Future research should focus on external validation, development of workflow-efficient volumetric tools, and exploration of patient-specific factors modulating the therapeutic ceiling.
Funding and ClinicalTrials.gov
The study was supported by a nationwide multicenter registry initiative in Korea. No specific clinical trial registration was referenced.
References
Kim H, Ryu WS, Inoue M, et al. Defining the Therapeutic Ceiling of Endovascular Thrombectomy in Large-Core Stroke: Beyond the Limits of ASPECTS. Stroke. 2026 Jul 6. PMID: 42403349. Available at: https://pubmed.ncbi.nlm.nih.gov/42403349/
Additional references on infarct volume and thrombectomy outcomes:
- Mlynash M, Lansberg MG, Olivot JM, et al. Refining the definition of the ischemic core in patients with acute stroke using computed tomography perfusion: Insights from the DEFUSE study. Stroke. 2011;42(2):336-341.
- Albers GW, Marks MP, Kemp S, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med. 2018;378(8):708-718.
- Penumbra Pivotal Stroke Trial Investigators. Safety and effectiveness of mechanical embolectomy in acute ischemic stroke: Results of the Penumbra pivotal stroke trial. Stroke. 2009;40(8):2765-2772.
