SEONGNAM — A recent study published in the journal Stroke indicates that quantitative infarct volumetry offers a more accurate prediction of patient outcomes than the Alberta Stroke Program Early CT Score (ASPECTS) for individuals undergoing endovascular therapy for large-core stroke. The study, conducted by Beom Joon Kim, MD and PhD, and colleagues at Seoul National University Bundang Hospital in Seongnam, Korea, identified 110 mL as a threshold for infarct volume beyond which the benefit of thrombectomy diminishes.

The Korean cohort study compared the prognostic value of quantitative volumetry against ASPECTS in patients treated with thrombectomy. Researchers observed a major discordance between CT-based ASPECTS and volumetric measurements within a nationwide Korean cohort undergoing endovascular therapy. Quantitative infarct volumetry, derived from diffusion-weighted imaging (DWI), CT perfusion, and noncontrast CT, demonstrated stronger prognostic performance than ASPECTS.

Patients who met the volumetric large-core definition based on diffusion-weighted imaging MRI experienced substantially worse functional outcomes, regardless of their ASPECTS status. The adjusted odds ratio for a poor functional outcome, defined as a 90-day modified Rankin Scale score of 5-6, was 6.92 (95% CI 2.58-19.34) for those meeting the volumetric large-core definition. In contrast, strokes classified as large core by ASPECTS but not by DWI volumetry were not independently associated with a poor outcome.

An ASPECTS-only large-core stroke had an 11.8% likelihood of a poor functional outcome, which was comparable to the 11.7% likelihood for volumetric small-core strokes. The study authors stated, "Quantitative volumetry provided better prognostic discrimination and identified ≥110 mL as a therapeutic ceiling where the benefit of thrombecomy becomes negligible." They added, "This suggests that the large-core benefit observed in prior trials may have been driven by patients below this volume threshold, masking the futility experienced by those with truly extensive necrosis."

ASPECTS is an ordinal, region-weighted scale used on noncontrast CT. Kim's group noted, "Its coarse, topographical thresholding can misrepresent infarct burden in either direction: small, scattered lesions spanning multiple regions can precipitate a disproportionately low score, thereby overestimating the biological infarct burden, whereas extensive yet subtle ischemic changes often evade visual detection, yielding deceptively preserved scores that underestimate the true extent of infarct."

The study encompassed a neuroimaging registry of 552 endovascular therapy-treated patients over two years in Korea. The average age of these patients was 70.4 years, with 57.8% being men. The median baseline NIH Stroke Scale score was 14, and intravenous thrombolysis was administered in 49.6% of cases. Successful reperfusion, defined as modified Thrombolysis in Cerebral Infarction grade 2b or 3, was achieved in 85.5% of cases. The median ASPECTS was 8, while median ischemic core volumes were 24.3 mL on DWI, 18.6 mL on CT perfusion, and 3.1 mL on noncontrast CT. The median last known well to groin puncture time was 4.2 hours.

The study authors concluded, "Although ASPECTS typically suffices for rapid triage, quantitative volumetry is imperative for resolving clinical ambiguity in borderline cases and, crucially, for defining the objective threshold where the benefit of reperfusion is eclipsed by the risk of futility." The researchers encouraged future prospective studies to focus on selecting strokes for endovascular therapy based on volumetric measurements.