Total and regional ASPECT score for non-contrast CT, CT angiography, and CT perfusion: inter-rater agreement and its association with the final infarction in acute ischemic stroke patients

Endovascular therapy versus medical management for acute ischemic stroke with large infarct core: Systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To compare the efficacy and safety of endovascular therapy (EVT) versus best medical management (BMM) in patients with acute ischemic stroke (AIS) with large infarct core.

METHODS

We searched Pubmed, Embase and Cochrane Central Register of Controlled Trials for published randomized clinical trials (RCTs) from inception to February 18, 2023. We defined patients with large core infarcts as having an Alberta Stroke Program early computed tomography score (ASPECTS) of 3-5. The primary outcome was functional independence, defined as a score of 0-2 on the modified Rankin scale (mRS) at 90 days. Secondary outcome was independent ambulation defined as mRS 0-3 at 90 days. Safety outcomes were mortality at 90 days, symptomatic intracranial hemorrhage (sICH) and any intracranial hemorrhage (ICH).

RESULTS

The overall treatment effect was more favourable to EVT group. EVT was significantly correlated with improvement of functional independence at 90 days (mRS 0-2) (RR = 2.40; 95 % CI, 1.82-3.16; P < 0.01; I2 = 0 %) and independent ambulation (mRS 0-3) (RR = 1,78; 95 % CI, 1.28-2.48; P < 0.01; I2 = 58 %) at 90 days. 90-day mortality was not significantly different between the two groups(RR = 0.95; 95 % CI, 0.78-1.16; P > 0.05; I2 = 0 %). The risk of sICH and any ICH was higher in EVT group than in BMM group.

CONCLUSION

Compared with BMM, EVT may improve functional outcomes in patients with ASPECTS 3-5, despite being associated with an increased risk of sICH and any ICH.

Predictors of ghost infarct core on baseline computed tomography perfusion in stroke patients with successful recanalization after mechanical thrombectomy

OBJECTIVES

To assess the predictors of ghost infarct core (GIC) in stroke patients achieving successful recanalization after mechanical thrombectomy (MT), based on final infarct volume (FIV) calculated from follow-up diffusion-weighted imaging (DWI).

METHODS

A total of 115 consecutive stroke patients who had undergone baseline computed tomography perfusion (CTP) scan, achieved successful recanalization after MT, and finished follow-up DWI evaluation were retrospectively enrolled. Ischemic core volume was automatically generated from baseline CTP, and FIV was determined manually based on follow-up DWI. Stroke-related risk factors and demographic, clinical, imaging, and procedural data were collected and assessed. Univariate and multivariate analyses were applied to identify the predictors of GIC.

RESULTS

Of the 115 included patients (31 women and 84 men; median age, 66 years), 18 patients (15.7%) showed a GIC. The GIC group showed significantly shorter time interval from stroke onset to CTP scan and that from stroke onset to recanalization (both p < 0.001), but higher ischemic core volume (p < 0.001), hypoperfused area volume (p < 0.001), mismatch area volume (p = 0.006), and hypoperfusion ratio (p = 0.001) than the no-GIC group. In multivariate analysis, time interval from stroke onset to CTP scan (odds ratio [OR], 0.983; p = 0.005) and ischemic core volume (OR, 1.073; p < 0.001) were independently associated with the occurrence of GIC.

CONCLUSIONS

In stroke patients achieving successful recanalization after MT, time interval from stroke onset to CTP and ischemic core volume are associated with the occurrence of GIC. Patients cannot be excluded from MT solely based on baseline CTP-derived ischemic core volume, especially for patients with a shorter onset time.

KEY POINTS

• Ghost infarct core (GIC) was found in 15.7% of patients with acute ischemic stroke (AIS) in our study cohort. • GIC was associated with stroke onset time, volumetric parameters derived from CTP, and collateral status indicated by HIR. • Time interval from stroke onset to CTP scan and ischemic core volume were independent predictors of GIC.

Diagnostic accuracy of using Alberta Stroke Program Early Computed Tomography Score on CT perfusion map to predict a target mismatch in patients with acute ischemic stroke

PURPOSE

To assess the diagnostic accuracy of using Alberta Stroke Program Early Computed Tomography Score (ASPECTS) on CT perfusion (CTP) map to predict a volumetric target mismatch in patients with acute ischemic stroke (AIS).

METHODS

Three-hundred and seven AIS patients with an onset time within 24h or unclear onset time who underwent CTP evaluation for large vessel occlusion of anterior circulation were enrolled. CTP ASPECTS was evaluated on cerebral blood flow (CBF) and time-to-maximum (Tmax) colored maps, respectively. Automated perfusion analysis software was used to calculate the volumes of ischemic core (volume_CBF<30%) and tissue at risk (volume_Tmax>6s). Target mismatch was defined as volume_{CBF< 30%}<70ml, volume_mismatch≥15ml, and volume_{Tmax >6s}/volume _{CBF< 30%}≥1.8. Spearman correlation and receiver operating characteristic curves were used for statistical analyses.

RESULTS

Strong correlations were found between CBF ASPECTS and volume_CBF<30%, and between Tmax ASPECTS and volume_Tmax>6s for overall population (ρ=-0.872, -0.757) and late-arriving patients (ρ=-0.900, -0.789). Mismatch ASPECTS moderately correlated with mismatch volume for overall population (ρ=0.498) and late-arriving patients (ρ=0.407). A CBF ASPECTS≥5 optimally predicted an ischemic core volume<70ml in overall population (sensitivity, 94.4%; specificity, 80.4%) and late-arriving patients (sensitivity, 89.5%; specificity, 90.5%). A CBF ASPECTS≥6 combined with a Mismatch ASPECTS≥1 optimally identified a target mismatch in overall population (sensitivity, 84.5%; specificity, 77.0%) and late-arriving patients (sensitivity, 83.7%; specificity, 90.0%).

CONCLUSION

CTP ASPECTS might be useful in predicting target mismatch derived from automated perfusion analysis software, and assisting in patient selection for endovascular therapy.