Ischemic Lesion Net Water Uptake Outperforms ASPECTS and CBF Less Than 30% in Predicting Futile Recanalization after Mechanical Thrombectomy.

Background Ischemic lesion net water uptake (NWU), a CT biomarker of cerebral edema, has been linked to poor outcomes in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). Whether NWU outperforms other imaging markers in predicting futile recanalization (FR) (ie, poor functional outcome despite successful endovascular thrombectomy [EVT]) remains uncertain. Purpose To evaluate the association between NWU and FR and compare the predictive performance of NWU with Alberta Stroke Program Early CT Score (ASPECTS) and CT perfusion (CTP)-derived relative cerebral blood flow less than 30% (rCBF30) volume. Materials and Methods This retrospective study included patients with AIS due to LVO who underwent pretreatment noncontrast CT, CT angiography, and CTP imaging at two comprehensive stroke centers (January 2019-December 2024) in whom successful reperfusion (modified Thrombolysis in Cerebral Infarction score of 2b-3) was achieved. NWU and ASPECTS were measured on admission CT images, and rCBF30 volume was derived from quantitative CTP maps. FR was defined as a 90-day modified Rankin Scale score of 3-6. Predictors of FR were identified through logistic regression. Discriminative ability was assessed through receiver operating characteristic analysis, with the Youden index used to determine the optimal NWU cutoff. Results Among 530 patients (median age, 75 years [IQR, 64-82.8 years]; 276 female patients), 312 (58.9%) had FR. Median NWU was higher in patients with FR than in those without (7.77% vs 2.75%; P < .001). In adjusted models, NWU (odds ratio [OR], 1.72 [95% CI: 1.53, 1.94]; P < .001), rCBF30 volume (OR, 1.01 [95% CI: 1.00, 1.02]; P < .005), and ASPECTS (OR, 0.79 [95% CI: 0.69, 0.90]; P < .001) were each associated with FR. NWU (AUC, 0.89 [95% CI: 0.86, 0.92]; P < .001 vs no discrimination) outperformed rCBF30 volume (AUC, 0.66 [95% CI: 0.64, 0.73]; P < .001 vs no discrimination) and ASPECTS (AUC, 0.65 [95% CI: 0.60, 0.70]; P < .001 vs no discrimination) in discriminative performance. Conclusion Admission CT NWU was associated with FR after EVT in patients with AIS due to LVO, and outperformed rCBF30 volume and ASPECTS in FR prediction. © RSNA, 2026.