Diffusion-weighted imaging-Alberta Stroke Research Articles

Association between the extent of diffusion restriction on brain diffusion-weighted imaging and neurological outcomes after an out-of-hospital cardiac arrest

BackgroundThis study evaluated the association between the extent of diffusion restriction on brain diffusion-weighted imaging (DWI) and neurological outcomes in patients who underwent targeted temperature management (TTM) after an out-of-hospital cardiac arrest (OHCA). MethodsPatients who underwent brain magnetic resonance imaging within 10 days of OHCA between 2012 and 2021 were analysed. The extent of diffusion restriction was described according to the modified DWI Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS). The 35 predefined brain regions were assigned a score if diffuse signal changes were concordantly present in DWI scans and apparent diffusion coefficient maps. The primary outcome was an unfavourable neurological outcome at 6 months. The sensitivity, specificity, and receiver operating characteristic (ROC) curves for the measured parameters were analysed. Cut-off values were determined to predict the primary outcome. The predictive cut-off DWI-ASPECTS was internally validated using five-fold cross-validation. ResultsOf the 301 patients, 108 (35.9%) had 6-month favourable neurological outcomes. Patients with unfavourable outcomes had higher whole-brain DWI-ASPECTS (median, 31 [26–33] vs. 0 [0–1], P < 0.001) than those with favourable outcomes. The area under the ROC curve (AUROC) of whole-brain DWI-ASPECTS was 0.957 (95% confidence interval [CI] 0.928–0.977). A cut-off value of ≥8 for unfavourable neurological outcomes had specificity and sensitivity of 100% (95% CI 96.6–100) and 89.6% (95% CI 84.4–93.6), respectively. The mean AUROC was 0.956. ConclusionMore extensive diffusion restriction on DWI-ASPECTS in patients with OHCA who underwent TTM was associated with 6-month unfavourable neurological outcomes.Running title: Diffusion restriction and neurological outcomes after cardiac arrest.

Acute middle cerebral artery occlusion caused by spontaneous thrombosis of a small internal carotid artery aneurysm: illustrative case

Spontaneous thrombosis of a saccular, unruptured, intracranial aneurysm is rare in nongiant aneurysms. Herein, the authors present a case of acute middle cerebral artery occlusion (MCO) caused by spontaneous thrombus of a small internal carotid artery (ICA) aneurysm. A 68-year-old woman presented with increased somnolence, right-sided hemiplegia, hemispatial neglect, and total aphagia. Left MCO and a small left ICA aneurysm were suspected based on magnetic resonance angiography (MRA). The authors detected early ischemic lesions from diffusion-weighted imaging (DWI). The DWI-Alberta Stroke Program Early Computed Tomography Score was 6. T2*-weighted imaging (T2*WI) showed a thrombus, the so-called susceptibility vessel sign, at the left MCO site. Another suspected thrombus was also found in the ipsilateral ICA aneurysm. The authors treated acute phase MCO with mechanical thrombectomy (MT), after which secondary stroke prophylaxis consisting of warfarin potassium was started. Since follow-up T2*WI showed the thrombus had disappeared from the left ICA aneurysm and the whole aneurysm was clarified by MRA, coil embolization was performed. After coil embolization, there was no ischemic recurrence. Aneurysms are infrequently found proximal to occlusion sites during MT. If the proximal aneurysm is a potential embolic source, treatment of the said aneurysm may prevent stroke.

Clinical Impact and Predictors of Diffusion Weighted Imaging(DWI) Reversal in Stroke Patients with Diffusion Weighted Imaging Alberta Stroke Program Early CT Score0-5 Treated by Thrombectomy : Diffusion Weighted Imaging Reversal in Large Volume Stroke.

To determine whether reversal of DWI lesions (DWIr) on the DWI-ASPECTS (diffusion weighted imaging Alberta Stroke Program CT Score) template should serve as apredictor of 90-day clinical outcome in acute ischemic stroke (AIS) patients with pretreatment diffusion-weighted imaging (DWI)-ASPECTS0-5 treated with thrombectomy, and to determine its predictors in current practice. We analyzed data of all consecutive patients included in the prospective multicenter national Endovascular Treatment in Ischemic Stroke Registry between 1 January 2015 and 31 December 2020 with apremorbid mRS ≤ 2, who presented with apretreatment DWI-ASPECTS 0-5score, underwent thrombectomy and had an available 24 h post-interventional MRI follow-up. Multivariable analyses were performed to evaluate the clinical impact of DWIr on early neurological improvement (ENI), 3‑month modified Rankin scale (mRS) score distribution (shift analysis) and to define independent predictors of DWIr. Early neurological improvement was detected in 82/211 (41.7%) of patients while 3‑month functional independence was achieved by75 (35.5%) patients. The DWI reversal (39/211, 18.9%) resulted an independent predictor of both ENI (aOR3.6, 95% CI 1.2-7.7; p0.018) and 3‑month clinical outcome (aOR for mRS shift:2.2, 95% CI 1-4.6; p0.030). Only successful recanalization (mTICI2c-3) independently predicted DWIr in the studied population (aOR3.3, 95% CI 1.3-7.9; p0.009). The DWI reversal occurs in anon-negligible proportion of DWI-ASPECTS0-5 patients subjected to thrombectomy and significantly influences clinical outcome. The mTICI2c-3 recanalization emerged as an independent DWIr predictor.

Penumbral Imaging-Based Thrombolysis with Tenecteplase Is Feasible up to 24 Hours after Symptom Onset.

BACKGROUND AND PURPOSE Thrombolysis >4.5 hours after ischemic stroke onset is unproven. We assessed the feasibility of tenecteplase (TNK) treatment in patients with evidence of an ischemic penumbra 4.5 to 24 hours after onset. METHODS Acute ischemic stroke patients underwent perfusion computed tomography (CT)/magnetic resonance imaging. Patients with cerebral blood volume (CBV) or diffusion weighted imaging Alberta Stroke Program Early CT Scores (ASPECTS) >6 and mismatch score >2 (defined as >2 ASPECTS regions with delay on mean transit time maps and normal CBV) were eligible for treatment with TNK (0.25 mg/kg). Patients with mismatch patterns enrolled in non-endovascular/non-thrombolysis trials and those without mismatch patterns served as comparators. RESULTS The median (interquartile range) baseline National Institutes of Health Stroke Scale (NIHSS) in TNK treated patients (n=16) was 12 (range, 8 to 15). In the untreated mismatch (n=18) and nonmismatch (n=23) groups, the baseline NIHSS was 12 (range, 7 to 12) and 16 (range, 8 to 20; P=0.09) respectively. There was one symptomatic hemorrhage each in the TNK group (parenchymal hematoma [PH] 2) and non-mismatch group (PH 2). Penumbral salvage volumes were higher in TNK treated patients (48.3 mL [range, 24.9 to 80.4]) than the non-mismatch (-90.8 mL [range, -197 to -20]; P<0.0001) patients. CONCLUSIONS This prospective, non-randomized study supports the feasibility of TNK therapy in patients with evidence of ischemic penumbra 4 to 24 hours after onset.

Penumbral Imaging-Based Thrombolysis with Tenecteplase Is Feasible up to 24 Hours after Symptom Onset.

Background and Purpose Thrombolysis >4.5 hours after ischemic stroke onset is unproven. We assessed the feasibility of tenecteplase (TNK) treatment in patients with evidence of an ischemic penumbra 4.5 to 24 hours after onset.Methods Acute ischemic stroke patients underwent perfusion computed tomography (CT)/magnetic resonance imaging. Patients with cerebral blood volume (CBV) or diffusion weighted imaging Alberta Stroke Program Early CT Scores (ASPECTS) >6 and mismatch score >2 (defined as >2 ASPECTS regions with delay on mean transit time maps and normal CBV) were eligible for treatment with TNK (0.25 mg/kg). Patients with mismatch patterns enrolled in non-endovascular/non-thrombolysis trials and those without mismatch patterns served as comparators.Results The median (interquartile range) baseline National Institutes of Health Stroke Scale (NIHSS) in TNK treated patients (n=16) was 12 (range, 8 to 15). In the untreated mismatch (n=18) and nonmismatch (n=23) groups, the baseline NIHSS was 12 (range, 7 to 12) and 16 (range, 8 to 20; P=0.09) respectively. There was one symptomatic hemorrhage each in the TNK group (parenchymal hematoma [PH] 2) and non-mismatch group (PH 2). Penumbral salvage volumes were higher in TNK treated patients (48.3 mL [range, 24.9 to 80.4]) than the non-mismatch (–90.8 mL [range, –197 to –20]; P<0.0001) patients.Conclusions This prospective, non-randomized study supports the feasibility of TNK therapy in patients with evidence of ischemic penumbra 4 to 24 hours after onset.

Abstract WMP3: Unknown Onset Strokes With Anterior Circulation Occlusion Treated by Thrombectomy After DWI-FLAIR Mismatch Selection

Background and Purpose: Unknown-onset strokes (UOS) have often been considered seperately from known-onset strokes (KOS), since emergency recanalization treatments are based on a time-window. Improvement in imaging-based selection and the advent of endovascular thrombectomy may lead us to reconsider this practice. Methods: We performed a retrospective, multicenter, cohort study of consecutive UOS treated by thrombectomy between December 2012 and December 2016. We compared UOS with proximal anterior circulation occlusion discovered beyond 6 hours from “last seen normal” with KOS for whom thrombectomy was started within 6 hours from onset. Time intervals from first found abnormal were recorded and compared with time intervals of KOS. Results were adjusted for age, initial National Institutes of Health Stroke Scale score, site of occlusion, diffusion weighted imaging Alberta Stroke Program Early CT Score, intravenous thrombolysis and use of general anesthesia. Results: Among 1246 strokes with anterior circulation occlusion treated by thrombectomy, 277 were UOS, with a “last time seen well” beyond 6 hours and DWI-FLAIR mismatch, and 865 were KOS who underwent groin puncture within 6 hours. Favorable outcome was achieved less often in UOS than KOS patients (45.2% vs. 53.9%, p=0.022). After pre-specified adjustment, this difference was not significant (adusted relative risk=0.91; 95%CI, 0.80 to 1.04; p=0.17). No differences in secondary outcomes were found except a marginal difference for excellent outcome (adjusted relative risk=0.83; 95%CI, 0.69 to 1.00; p=0.052), Time intervals from “first found abnormal” were significantly longer in UOS. Conclusion: Endovascular treatment of unknown-onset strokes with anterior circulation occlusion and DWI-FLAIR mismatch appears to be as safe and efficient as endovascular treatment of known-onset strokes within 6 hours from onset. This pattern of imaging could be used for patient selection when time of onset is unknown.

Large Ischemic Lesions on Diffusion-Weighted Imaging Done Before Intravenous Tissue Plasminogen Activator Thrombolysis Predicts a Poor Outcome in Patients With Acute Stroke

MRI is useful for detecting early ischemic lesions before administration of tissue plasminogen activator in patients with hyperacute ischemic stroke. However, it is unclear whether early ischemic change seen on diffusion-weighted imaging (DWI) can be used to predict patient outcomes. Consecutive patients with anterior circulation ischemic stroke treated with tissue plasminogen activator within 3 hours of stroke onset were prospectively studied. The National Institutes of Health Stroke Scale score was obtained before and 7 days after tissue plasminogen activator administration. MRI, including DWI, was done before tissue plasminogen activator thrombolysis. The relationship between the DWI Alberta Stroke Programme Early CT Score (ASPECTS) and patients' outcomes was assessed. The subjects consisted of 49 consecutive patients with stroke (27 males; mean age, 72.9+/-10.3 years). The median (range) of the baseline DWI ASPECTS value was 9 (3-10). Dramatic improvement was seen in one of 8 patients with an ASPECTS < or = 5 compared with 21 of 41 patients with a DWI ASPECTS > 5 (P=0.0592). On the other hand, worsening was noted more frequently in patients with a DWI ASPECTS < or = 5 (3 of 8 patients) than in patients with an ASPECTS > 5 (4 of 41 patients; P=0.0753). Bad outcome was seen more frequently in patients with a DWI ASPECTS < or = 5 (6 of 8 patients) than in patients with a DWI ASPECTS > 5 (2 of 41 patients; P<0.0001). Multivariate logistic regression analysis demonstrated that a DWI ASPECTS < or = 5 was the only independent predictor of a bad outcome (OR, 33.4; 95% CI, 2.7 to 410.8; P=0.0062). DWI ASPECTS appears to be a reliable tool for predicting bad outcome. Patients with a DWI ASPECTS > 5 should be considered eligible for tissue plasminogen activator therapy.