Whole-brain dynamic time-resolved computed tomography angiography (CTA) is a technique developed on the new 320-detector row CT scanner capable of generating time-resolved cerebral angiograms from skull base to vertex. Unlike a conventional cerebral angiogram, this technique visualizes pial arterial filling in all vascular territories, thereby providing additional hemodynamic information. Ours was a retrospective study of consecutive patients with ischemic stroke and M1 middle cerebral artery þ / À intracranial internal carotid artery occlusions presenting to our center from June 2010 and undergoing dynamic timeresolved CTA and perfusion CT within 6 hours of symptom onset. Leptomeningeal collateral status was assessed by determining relative prominence of pial arteries in the ischemic region, rate and extent of retrograde flow, and various topographical patterns of pial arterial filling. Twenty-five patients were included in the study. We demonstrate the existence of the following novel properties of leptomeningeal collaterals in humans: (a) posterior (posterior cerebral artery (PCA)-MCA) dominant collateralization, (b) intraterritorial 'within MCA region' leptomeningeal collaterals, and (c) significant variability in size, extent, and retrograde filling time in pial arteries. We also describe a simple and reliable collateral grading template that, for the first time on dynamic CTA, incorporates back-filling time as well as size and extent of collateral filling.

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Objective:To investigate the efficacy of tenecteplase (TNK), a genetically modified variant of alteplase with greater fibrin specificity and longer half-life than alteplase, prior to endovascular thrombectomy (EVT) in patients with basilar artery occlusion (BAO).Methods:To determine whether tenecteplase is associated with better reperfusion rates than alteplase prior to EVT in BAO, clinical and procedural data of consecutive BAO patients from the Basilar Artery Treatment and MANagement (BATMAN) registry and the Tenecteplase versus Alteplase before Endovascular Therapy for Ischemic Stroke (EXTEND-IA TNK) trial were retrospectively analyzed. Reperfusion >50% or absence of retrievable thrombus at the time of the initial angiogram was evaluated.Results:We included 110 BAO patients treated with intravenous thrombolysis prior to EVT [mean age 69(SD 14); median NIHSS 16(IQR 7-32)]. Nineteen patients were thrombolysed with TNK (0.25mg/kg or 0.40mg/kg) and 91 with alteplase (0.9mg/kg). Reperfusion>50% occurred in 26% (n=5/19) of patients thrombolysed with TNK vs 7% (n=6/91) thrombolysed with alteplase (RR 4.0 95%CI 1.3-12; p=0.02), despite shorter thrombolysis-to-arterial-puncture time in the TNK-treated patients (48[IQR 40-71]mins) vs alteplase-treated patients (110[IQR 51-185]mins, p=0.004). No difference in symptomatic intracranial hemorrhage was observed (0/19(0%) TNK, 1/91(1%) alteplase, p=0.9).Conclusions:Tenecteplase may be associated with an increased rate of reperfusion in comparison with alteplase before EVT in BAO. Randomized controlled trials to compare tenecteplase with alteplase in BAO patients are warranted.Classification of evidence:This study provides Class III evidence that tenecteplase leads to higher reperfusion rates in comparison with alteplase prior to EVT in BAO patients.

7However, these criteria were largely empirically derived from limited cohorts and using earlier generation scanners and software. We hypothesized that in individual patients, advanced imaging profiles will accurately predict 3-month functional Background and Purpose-Advanced imaging to identify tissue pathophysiology may provide more accurate prognostication than the clinical measures used currently in stroke. This study aimed to derive and validate a predictive model for functional outcome based on acute clinical and advanced imaging measures. Methods-A database of prospectively collected sub-4.5 hour patients with ischemic stroke being assessed for thrombolysis from 5 centers who had computed tomographic perfusion and computed tomographic angiography before a treatment decision was assessed. Individual variable cut points were derived from a classification and regression tree analysis. The optimal cut points for each assessment variable were then used in a backward logic regression to predict modified Rankin scale (mRS) score of 0 to 1 and 5 to 6. The variables remaining in the models were then assessed using a receiver operating characteristic curve analysis. Results-Overall, 1519 patients were included in the study, 635 in the derivation cohort and 884 in the validation cohort.The model was highly accurate at predicting mRS score of 0 to 1 in all patients considered for thrombolysis therapy (area under the curve [AUC] 0.91), those who were treated (AUC 0.88) and those with recanalization (AUC 0.89). Next, the model was highly accurate at predicting mRS score of 5 to 6 in all patients considered for thrombolysis therapy (AUC 0.91), those who were treated (0.89) and those with recanalization (AUC 0.91). The odds ratio of thrombolysed patients who met the model criteria achieving mRS score of 0 to 1 was 17.89 (4.59-36.35, P<0.001) and for mRS score of 5 to 6 was 8.23 (2.57-26.97, P<0.001). Conclusions-This study has derived and validated a highly accurate model at predicting patient outcome after ischemic stroke.

See Saver (doi:) for a scientific commentary on this article.The extent to which CT perfusion imaging variables before and after reperfusion therapy for stroke predict the length of subsequent disability-free life is unclear. Kawano et al. show that saving a millilitre of penumbra translates into benefits equivalent to more than a week of disability-free life.

This large observational cohort suggests that a portion of ischemic stroke patients clinically eligible for alteplase therapy with a small perfusion lesion have a good natural history and may not benefit from treatment. Ann Neurol 2016;80:286-293.

White matter hypoperfusion remote to the acutely ischemic region on CTP is a marker of small vessel disease and was associated with increased HT, larger acute infarct cores, and greater infarct growth.

Background and Purpose: This study aimed to explore whether the therapeutic benefit of endovascular thrombectomy (EVT) was mediated by core growth rate. Methods: This retrospective cohort study identified acute ischemic stroke patients with large vessel occlusion and receiving reperfusion treatment, either EVT or intravenous thrombolysis (IVT), within 4.5 hours of stroke onset. Patients were divided into 2 groups: EVT versus IVT only patients (who had no access to EVT). Core growth rate was estimated by the acute core volume on perfusion computed tomography divided by the time from stroke onset to perfusion computed tomography. The primary clinical outcome was good outcome defined by 3-month modified Rankin Scale score of 0–2. Tissue outcome was the final infarction volume. Results: A total of 806 patients were included, 429 in the EVT group (recanalization rate of 61.6%) and 377 in the IVT only group (recanalization rate of 44.7%). The treatment effect of EVT versus IVT only was mediated by core growth rate, showing a significant interaction between EVT treatment and core growth rate in predicting good clinical outcome (interaction odds ratio=1.03 [1.01–1.05], P =0.007) and final infarct volume (interaction odds ratio=−0.44 [−0.87 to −0.01], P =0.047). For patients with fast core growth of >25 mL/h, EVT treatment (compared with IVT only) increased the odds of good clinical outcome (adjusted odds ratio=3.62 [1.21–10.76], P =0.021) and resulted in smaller final infarction volume (37.5 versus 73.9 mL, P =0.012). For patients with slow core growth of <15 mL/h, there were no significant differences between the EVT and the IVT only group in either good clinical outcome (adjusted odds ratio=1.44 [0.97–2.14], P =0.070) or final infarction volume (22.6 versus 21.9 mL, P =0.551). Conclusions: Fast core growth was associated with greater benefit from EVT compared with IVT in the early <4.5-hour time window.