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BACKGROUND: Pretreatment CT Perfusion (CTP) parameters serve as reliable surrogates of collateral status (CS). In this study, we aim to assess the relationship between the novel compensation index (CI, Tmax > 4 s/Tmax > 6 s) and already established CTP collateral markers, namely cerebral blood volume (CBV) index and Hypoperfusion Intensity Ratio (HIR), with the reference standard American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score (CS) on DSA. METHODS: In this retrospective study, inclusion criteria were the following: (a) CT angiography confirmed anterior circulation large vessel occlusion from 9 January 2017 to 10 January 2023; (b) diagnostic CT perfusion; and (c) underwent mechanical thrombectomy with documented DSA-CS. Student t-test, Mann-Whitney-U-test and Chi-square test were used to assess differences. Spearmans rank correlation and logistic regression analysis were used to assess associations. p ≤ 0.05 was considered significant. RESULTS: In total, 223 patients (mean age: 67.8 ± 15.8, 56% female) met our inclusion criteria. The CI (ρ = 0.37, p < 0.001) and HIR (ρ = -0.29, p < 0.001) significantly correlated with DSA-CS. Whereas the CBV Index (ρ = 0.1, p > 0.05) did not correlate with DSA-CS. On multivariate logistic regression analysis taking into account age, sex, ASPECTS, tPA, premorbid mRS, NIH stroke scale, prior history of TIA, stroke, atrial fibrillation, diabetes mellitus, hyperlipidemia, heart disease and hypertension, only CI was not found to be independently associated with DSA-CS (adjusted OR = 1.387, 95% CI: 1.09-1.77, p < 0.01). CONCLUSION: CI demonstrates a stronger correlation with DSA-CS compared to both the HIR and CBV Index where it may show promise as an additional quantitative pretreatment CS biomarker.

Background Unfavorable clinical outcomes in patients with acute ischemic stroke caused by large‐vessel occlusions despite successful reperfusion have been associated with poor venous outflow. The objective of this study is to assess the relationship between prolonged venous transit (PVT), a novel perfusion imaging surrogate for poor venous outflow, and likelihood of favorable clinical recovery. Methods In this retrospective review of prospectively collected data of consecutive patients (2017–2022) with successfully reperfused, anterior circulation acute ischemic stroke caused by large‐vessel occlusions, we assessed the association between PVT+, defined as time to maximum ≧10‐second timing delays within either the posterior superior sagittal sinus, torcula, or both regions on pretreatment perfusion imaging, and favorable clinical outcomes defined as 90‐day modified Rankin Scale score of 0 to 2. Patients were dichotomized into PVT+ and PVT− for analysis. Multivariable logistic regression analyses for favorable recovery were performed with demographic variables and stroke characteristics. Results A total of 127 consecutive patients (median age, 71 [interquartile range 61—77] years; 59.1% women) were included, and 40 of 127 (31.5%) were PVT+. PVT+ (adjusted odds ratio [aOR], 0.23 [95% CI, 0.07–0.81]; P = 0.02) and advanced age (aOR, 0.92 [95% CI, 0.88–0.97]; P = 0.01) were significantly associated with the primary outcome. Conclusion PVT+ was associated with a lower likelihood of achieving favorable clinical recovery in successfully reperfused patients with acute ischemic stroke caused by large vessel occlusion. PVT may serve as a clinically useful adjunctive imaging parameter.

Background Hemorrhagic transformation (HT) is a major complication in patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy. However, HT in patients with AIS due to medium‐vessel occlusions has still not been well researched. In large‐vessel occlusions, collateral status is an important determinant of postprocedural HT, and the cerebral blood volume (CBV) index is a reliable surrogate of collateral status. The aim of our study is to identify an optimal CBV index threshold associated with HT in patients with AIS due to medium‐vessel occlusion and evaluate additional parameters that are independently associated with HT in this group. Methods This retrospective analysis of our prospectively collected database from 2 comprehensive stroke centers consisted of patients presenting with AIS due to medium‐vessel occlusion from 2019 to 2023. The primary outcome was the presence of HT on follow‐up imaging. Optimal CBV index cutoff for HT was derived from a univariate logistic regression analysis. Multivariable logistic regression analysis for HT was derived from the dichotomized CBV index and other covariates. The receiver operator characteristic curve yielded area under the curve. Statistical significance was P≤$ \le $0.05. Results Of 111 patients (median age, 70 years; 43.2% women) included, 26 (23.4%) patients had HT. The optimal CBV index cutoff was 0.7. From multivariable regression analysis, significant variables included prior stroke (adjusted odds ratio [aOR], 7.18 [95% CI, 1.60–32.16]; P = 0.01), endovascular thrombectomy attempt (aOR, 7.86 [95% CI, 1.78–34.68]; P = 0.01), and CBV index (≤$ \le $ 0.7; aOR, 4.23 [95% CI, 1.02–17.59]; P = 0.04). The area under the curve was 0.82 (95% CI, 0.69–0.91). Conclusion A CBV index ≤$ \le $ 0.7 was independently associated with HT in patients with AIS due to medium‐vessel occlusion. Endovascular thrombectomy attempt and prior stroke history were also independently associated with HT in this population.

Background In patients with acute ischemic stroke secondary to large vessel occlusion, achieving modified Thrombolysis in Cerebral Infarction (mTICI) 2c/3 (excellent recanalization) over mTICI 2b is associated with improved functional outcomes. We aimed to determine pretreatment and interventional parameters that are independently associated with mTICI 2c/3 over 2b reperfusion in patients who underwent technically successful mechanical thrombectomy. Methods In this retrospective study, consecutive patients with acute ischemic stroke with anterior circulation large vessel occlusion achieving mTICI 2b/2c/3 recanalization after mechanical thrombectomy were included. We evaluated the association between pretreatment clinical, imaging, and interventional parameters in patients who achieved mTICI 2c/3 versus 2b using multivariate logistic regressions. Results From May 11, 2019 to October 9, 2022, 149 consecutive patients met our inclusion criteria (median 70 years old [interquartile range 65–78.5], 57.7% female). Adjusted multivariate regression analyses showed that patients with excellent recanalization had lower admission National Institutes of Health Stroke Scale scores (adjusted odds ratio [aOR], 0.93; P=0.036), were less likely to have a history of diabetes (aOR, 0.42; P=0.050) and prior stroke (aOR, 0.27; P=0.007), had a cerebral blood volume index ≥0.7 (aOR, 3.75; P=0.007), and were more likely to achieve excellent recanalization with aspiration alone (aOR, 2.89; P=0.012). A multivariate logistic regression model comprising these independent factors predicted mTICI 2c/3 with an area under the curve 0.79 (95% CI, 0.68–0.86; P

Objective: To assess pretreatment and interventional parameters as predictors of favorable Activity Measure for Post-Acute Care (AM-PAC) scores for optimal discharge planning. Design: In this prospectively collected, retrospectively reviewed multicenter study from 9/1/2017 to 9/22/2022, patients were dichotomized into favorable and unfavorable AM-PAC. Multivariate logistic regression and receiver operator characteristics analyses were performed for the identified significant variables. A P value of ≤.05 was significant. Setting: Hospitalized care. Participants: In total, 229 patients (mean ±SD 70.65 ±15.2 [55.9% women]) met our inclusion criteria. Inclusion criteria were (a) computed tomography (CT) angiography confirmed LVO from 9/1/2017 to 9/22/2022; (b) diagnostic CT perfusion; and (c) available AM-PAC scores. Interventions: None. Main Outcome Measures: Favorable AM-PAC, defined as a daily activity score ≥19 and basic mobility score of ≥17. Results: Patients with favorable AM-PAC were younger (61.3 vs 70.7, P

Background For acute proximal intracranial artery occlusions, contact aspiration may be more effective than stent‐retriever for first‐line reperfusion therapy. Due to the lack of data regarding medium vessel occlusion thrombectomy, we evaluated outcomes according to first‐line technique in a large, multicenter registry. Methods Imaging, procedural, and clinical outcomes of patients with acute proximal medium vessel occlusions (M2, A1, or P1) or distal medium vessel occlusions (M3, A2, P2, or further) treated at 37 sites in 10 countries were analyzed according to first‐line endovascular technique (stent‐retriever versus aspiration). Multivariable logistic regression and propensity‐score matching were used to estimate the odds of the primary outcome, expanded Thrombolysis in Cerebral Infarction score of 2b–3 (“successful recanalization”), as well as secondary outcomes (first‐pass effect, expanded Thrombolysis in Cerebral Infarction 2c‐3, intracerebral hemorrhage, and 90‐day modified Rankin scale, 90‐day mortality) between treatment groups. Results Of the 440 included patients (44.5% stent‐retriever versus 55.5% aspiration), those treated with stent‐retriever had lower baseline Alberta Stroke Program Early Computed Tomography Scale scores (median 8 versus 9; P

Background and Purpose The benefit of endovascular thrombectomy (EVT) treatment is still unclear in stroke patients presenting with extensive baseline infarct. The use of additional imaging biomarkers could improve clinical outcome prediction and individualized EVT selection in this vulnerable cohort. We hypothesized that cerebral venous outflow (VO) may be associated with functional outcomes in patients with low Alberta Stroke Program Early CT Score (ASPECTS). Methods We conducted a retrospective multicenter cohort study of patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO). Extensive baseline infarct was defined by an ASPECTS of ≤5 on admission computed tomography (CT). VO profiles were assessed on admission CT angiography using the Cortical Vein Opacification Score (COVES). Favorable VO was defined as COVES ≥3. Multivariable logistic regression was used to determine the association between cerebral VO and good clinical outcomes (90-day modified Rankin Scale score of ≤3). Results A total of 98 patients met the inclusion criteria. Patients with extensive baseline infarct and favorable VO achieved significantly more often good clinical outcomes compared to patients with unfavorable VO (45.5% vs. 10.5%, P

Objectives: We sought to assess whether there were any parameter(s) on baseline computed-tomography-perfusion (CTP) strongly correlating with final-infarct-volume, and infarct volume progression after endovascular recanalization of acute ischemic stroke (AIS) with primary distal, medium vessel occlusion (DMVO). Materials and Methods: We performed a retrospective analysis of consecutive AIS patients who were successfully recanalized by thrombectomy for DMVO. By comparing baseline CTP and follow-up MRI, we evaluated the correlation between baseline infarct and hypoperfusion volumes, and final infarct volume and infarct volume progression. We also examined their effect on good clinical outcome at 3 months (defined as an mRS score of 0 to 2). Results: Between January 2018 and January 2021, 38 patients met the inclusion criteria (76% [29/38] female, median age 75 [66–86] years). Median final infarct volume and infarct volume progression were 8.4 mL [IQR: 5.2–44.4] and 7.2 mL [IQR: 4.3–29.1] respectively. TMax>10 sec volume was strongly correlated with both (r=0.831 and r=0.771 respectively, p10 sec volume increased the probability of a higher final-infarct-volume (r2=0.690, coefficient = 0.83 [0.64–1.00], p10 sec volume on baseline CTP correlates strongly with final infarct volume as well as with clinical outcome after mechanical thrombectomy for an AIS with DMVO.

Background: Pretreatment CT Perfusion (CTP) parameters serve as reliable surrogates of collateral status (CS). In this study, we aim to assess the relationship between the novel compensation index (CI, Tmax > 4 s/Tmax > 6 s) and already established CTP collateral markers, namely cerebral blood volume (CBV) index and Hypoperfusion Intensity Ratio (HIR), with the reference standard American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score (CS) on DSA. Methods: In this retrospective study, inclusion criteria were the following: (a) CT angiography confirmed anterior circulation large vessel occlusion from 9 January 2017 to 10 January 2023; (b) diagnostic CT perfusion; and (c) underwent mechanical thrombectomy with documented DSA-CS. Student t-test, Mann–Whitney-U-test and Chi-square test were used to assess differences. Spearman’s rank correlation and logistic regression analysis were used to assess associations. p ≤ 0.05 was considered significant. Results: In total, 223 patients (mean age: 67.8 ± 15.8, 56% female) met our inclusion criteria. The CI (ρ = 0.37, p < 0.001) and HIR (ρ = −0.29, p < 0.001) significantly correlated with DSA-CS. Whereas the CBV Index (ρ = 0.1, p > 0.05) did not correlate with DSA-CS. On multivariate logistic regression analysis taking into account age, sex, ASPECTS, tPA, premorbid mRS, NIH stroke scale, prior history of TIA, stroke, atrial fibrillation, diabetes mellitus, hyperlipidemia, heart disease and hypertension, only CI was not found to be independently associated with DSA-CS (adjusted OR = 1.387, 95% CI: 1.09–1.77, p < 0.01). Conclusion: CI demonstrates a stronger correlation with DSA-CS compared to both the HIR and CBV Index where it may show promise as an additional quantitative pretreatment CS biomarker.

Background and purposeStent and balloon anchor techniques have been described to obtain distal support and straighten catheter loops, stabilize microcatheters in giant aneurysms, or access distal tortuous anatomy during thrombectomy. These techniques require catheterization of distal arteries with a microcatheter but tortuosity and length issues may render it challenging, precluding the distal unsheathing of a classical auto-expandable stentretriever with the anchor technique.MethodsTherefore, we developed the so-called Anch'Or Harpoon Technique using a manually expandable stent retriever, the Tigertriever 13 (Rapid Medical, Yoqneam, Israel). Here, the stent retriever is not unsheathed but pushed out of a microcatheter, and then advanced as far as possible before manual opening.Results and conclusionThis technique may be used in 2 different situations. First, in the case of vessel tortuosity if the microcatheter can't be advanced as far as the physician wants: the Tigertriever 13 could be delivered through the microcatheter without having to unsheathe it, and be advanced and opened distally to its microcatheter to establish a stable anchor prior to advancing the guiding, intermediate, and micro-catheters (Anchor technique). The second situation is when distal occlusions lead to length issues; the microcatheter may be too short to cross a distal clot: the Tigertriever 13 could then be pushed out of the microcatheter, and be used to cross a sub-occlusive clot as it has a soft shaped distal tip and the physician has a visual on the artery beyond the sub-occlusion. Then, the Tigertriever would be manually expanded through the clot and retrieved (Harpoon technique) to obtain a recanalization.

Background When standard endovascular thrombectomy techniques fail to achieve a successful recanalization, it is often necessary to use rescue therapies (RTs). RTs are more commonly used in basilar artery occlusions and conventionally thought to represent “a last resort option.” We sought to study the outcomes of basilar artery occlusion patients who received RT, and further hypothesize that the number of instrumental passes before initiation of RT may be associated with increased risk for poor clinical outcomes. Methods We performed a retrospective analysis of the ETIS (“Endovascular Treatment in Ischemic Stroke”) registry. Our primary analysis included 277 patients who underwent thrombectomy for basilar artery occlusion, of whom 74 patients (26.7%) who received RT, defined as the use of intra‐arterial drugs, angioplasty, or stenting. Primary outcome measures included successful or complete reperfusion (final modified thrombolysis in cerebral infarction ≥2b or 3), functional independence (modified Rankin scale of 0–2), and mortality at 3 months. Results RT patients were more likely to have an atherosclerotic cause than non‐RT patients (46/74 [62.2%] versus 38/203 [18.7%]), were more likely to die (42/74 [56.8%] versus 73/203 [36.0%]), and were less likely to achieve functional independence (12/74 [16.2%] versus 84/203 [41.4%]). In the RT cohort, 17 of 74 patients (23.0%) had 1 pass before RT initiation, and 8 of 17 (47.1%) achieved a modified Rankin scale score of 0 to 2 at 3 months, with a mortality rate of 23.5% (4/17). The chance of achieving good clinical outcome decreased with each additional pass, whereas mortality increased. The odds of mortality at 3 months were highest in the >3 passes group, with an odds ratio of 10.29 (95% CI, 2.42–43.81) compared with 1 pass. None of the 25 patients with >3 passes before RT achieved 3‐month functional independence. Conclusions There is a significant correlation between the number of passes before initiation of RT and 3‐month clinical outcomes in basilar artery occlusion patients.

Background and PurposeGood clinical outcome predictors have been established in mechanical thrombectomy (MT) for acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). An early neurological improvement (ENI), defined as a reduction of ≥8 on the National Institutes of Health Stroke Scale (NIHSS), compared with the baseline score or an NIHSS of 0 or 1 at 24 h after MT, is a strong predictor of favorable outcome. We aimed to study the impact of ENI after MT for distal medium vessel occlusions (DMVO).MethodsWe retrospectively analyzed the data of consecutive patients who underwent MT for a primary DMVO in one large academic center. We compared clinical outcomes between patients with DMVO stratified by ENI. Multivariate analyses were performed to determine the impact of ENI on good 90-day outcome (modified Rankin scale of 0–2) and identify factors contributing to ENI.ResultsBetween January 2018 and January 2021, 61 patients underwent an MT for an AIS with a primary DMVO. An ENI was seen in 24 (39%) patients (ENI+). Outcomes were significantly better in ENI+ patients, with 83% achieving a good outcome at 3 months vs. 43% for patients without ENI (ENI–; p = 0.019). ENI was an independent predictive factor of good clinical outcome even after adjusting for potential confounding factors [odds ratio 12.49 (1.49–105.01), p = 0.020]. The use of intravenous tissue plasminogen activator [IVtPA; Odds-ratio 6.59 (1.82–23.89), p = 0.004] was a positive predictor of ENI.ConclusionENI at day 1 following MT for DMVO stroke is a strong independent predictor of good to excellent 3-month clinical outcome.

IntroductionCurrent guidelines suggest that perfusion imaging should only be performed > 6 h after symptom onset. Pathophysiologically, brain perfusion should matter whatever the elapsed time. We aimed to compare relative contribution of recanalization time and stroke core volume in predicting functional outcome in patients treated by endovascular thrombectomy within 6-h of stroke-onset.MethodsConsecutive patients presenting between January 2015 and June 2021 with (i) an acute ischaemic stroke due to an anterior proximal occlusion, (ii) a successful thrombectomy (TICI >2a) within 6-h of symptom-onset and (iii) CT perfusion imaging were included. Core stroke volume was automatically computed using RAPID software. Two linear regression models were built that included in the null hypothesis the pre-treatment NIHSS score and the hypoperfusion volume (Tmax > 6 s) as confounding variables and 24 h post-recanalization NIHSS and 90 days mRS as outcome variables. Time to recanalization was used as covariate in one model and stroke core volume as covariate in the other.ResultsFrom a total of 377 thrombectomies, 94 matched selection criteria. The Model null hypothesis explained 37% of the variability for 24 h post-recanalization NIHSS and 42% of the variability for 90 days MRS. The core volume as covariate increased outcome variability prediction to 57 and 56%, respectively. Time to recanalization as covariate marginally increased outcome variability prediction from 37 and 34% to 40 and 42.6%, respectively.ConclusionCore stroke volume better explains outcome variability in comparison to the time to recanalization in anterior large vessel occlusion stroke with successful thrombectomy done within 6 h of symptoms onset. Still, a large part of outcome variability prediction fails to be explained by the usual predictors.

The hypoperfusion intensity ratio (HIR) is associated with collateral status and reflects the impaired microperfusion of brain tissue in patients with acute ischemic stroke and large vessel occlusion (AIS-LVO). As a deterioration in cerebral blood flow is associated with brain edema, we aimed to investigate whether HIR is correlated with the early edema progression rate (EPR) determined by the ischemic net water uptake (NWU) in a multicenter retrospective analysis of AIS-LVO patients anticipated for thrombectomy treatment. HIR was automatically calculated as the ratio of time-to-maximum (TMax) > 10 s/(TMax) > 6 s. HIRs < 0.4 were regarded as favorable (HIR+) and ≥0.4 as unfavorable (HIR−). Quantitative ischemic lesion NWU was delineated on baseline NCCT images and EPR was calculated as the ratio of NWU/time from symptom onset to imaging. Multivariable regression analysis was used to assess the association of HIR with EPR. This study included 731 patients. HIR+ patients exhibited a reduced median NWU upon admission CT (4% (IQR: 2.1–7.6) versus 8.2% (6–10.4); p < 0.001) and less median EPR (0.016%/h (IQR: 0.007–0.04) versus 0.044%/h (IQR: 0.021–0.089; p < 0.001) compared to HIR− patients. Multivariable regression showed that HIR+ (β: 0.53, SE: 0.02; p = 0.003) and presentation of the National Institutes of Health Stroke Scale (β: 0.2, SE: 0.0006; p = 0.001) were independently associated with EPR. In conclusion, favorable HIR was associated with lower early edema progression and decreased ischemic edema formation on baseline NCCT.

Objectives: The susceptibility-vessel-sign (SVS) allows thrombus visualization, length estimation and composition, and it may impact reperfusion during mechanical thrombectomy (MT). SVS can also describe thrombus shape in the occluded artery: in the straight M1-segment (S-shaped), or in an angulated/traversing a bifurcation segment (A-shaped). We determined whether SVS clot shape influenced reperfusion and outcomes after MT for proximal middle-cerebral-artery (M1) occlusions.Methods: Between May 2015 and March 2018, consecutive patients who underwent MT at one comprehensive stroke center and who had a baseline MRI with a T2* sequence were included. Clinical, procedural and radiographic data, including clot shape on SVS [angulated/bifurcation (A-SVS) vs. straight (S-SVS)] and length were assessed. Primary outcome was successful reperfusion (TICI 2b-3). Secondary outcome were MT complication rates, MT reperfusion time, and clinical outcome at 90-days. Predictors of outcome were assessed with univariate and multivariate analyses.Results: A total of 62 patients were included. 56% (35/62) had an A-SVS. Clots were significantly longer in the A-SVS group (19 mm vs. 8 mm p = 0.0002). Groups were otherwise well-matched with regard to baseline characteristics. There was a significantly lower rate of successful reperfusion in the A-SVS cohort (83%) compared to the S-SVS cohort (96%) in multivariable analysis [OR 0.04 (95% CI, 0.002–0.58), p = 0.02]. There was no significant difference in long term clinical outcome between groups.Conclusion: Clot shape as determined on T2* imaging, in patients presenting with M1 occlusion appears to be a predictor of successful reperfusion after MT. Angulated and bifurcating clots are associated with poorer rates of successful reperfusion.

Objectives: Baseline-core-infarct volume is a critical factor in patient selection and outcome in acute ischemic stroke (AIS) before mechanical thrombectomy (MT). We determined whether oxygen extraction efficiency and arterial collaterals, two different physiologic components of the cerebral ischemic cascade, interacted to modulate baseline-core-infarct volume in patients with AIS-LVO undergoing MT triage.Methods: Between January 2015 and March 2018, consecutive patients with an AIS and M1 occlusion considered for MT with a baseline MRI and perfusion-imaging were included. Variables such as baseline-core-infarct volume [mL], arterial collaterals (HIR: TMax > 10 s volume/TMax > 6 s), high oxygen extraction (HOE, presence of the brush-sign on T2*) were assessed. A linear-regression was used to test the interaction of HOE and HIR with baseline-core-infarct volume, after including potential confounding variables.Results: We included 103 patients. Median age was 70 (58–78), and 63% were female. Median baseline-core-infarct volume was 32 ml (IQR 8–74.5). Seventy six patients (74%) had HOE. In a multivariate analysis both favorable HIR collaterals (p = 0.02) and HOE (p = 0.038) were associated with lower baseline-core-infarct volume. However, HOE significantly interacted with HIR (p = 0.01) to predict baseline-core-infarct volume, favorable collaterals (low HIR) with HOE was associated with small baseline-core-infarct whereas patients with poor collaterals (high HIR) and HOE had large baseline-core-infarct.Conclusion: While HOE under effective collateral blood-flow has the lowest baseline-core-infarct volume of all patients, the protective effect of HOE reverses under poor collateral blood-flow and may be a maladaptive response to ischemic stroke as measured by core infarctions in AIS-LVO patients undergoing MT triage.

Background: Hemorrhagic transformation after acute ischemic stroke is a dreaded and severe complication of thrombolysis and thrombectomy. However, its detection on post-thrombectomy conventional non-contrast computed tomography (CT) scan can be complicated by the frequent (and sometimes concomitant) presence of contrast, resulting in changes in management.Aims: Our objective was to assess the inter- and intra-rater reliability for the detection of blood and/or contrast on day-1 post-thrombectomy CT scans.Methods: A total of 18 raters across 3 different specialties independently examined 30 post-thrombectomy CT scans selected from the Aspiration vs. STEnt-Retriever (ASTER) trial. They were asked to judge the presence of blood and contrast. Thirty days later, the same 18 raters again independently judged the 30 scans, in randomized order. Agreement was measured with Fleiss' and Cohen's K statistics.Results: Overall agreement on blood and/ or contrast presence was only fair, k = 0.291 (95% CI = 0.273–0.309). There were 0 scans with consensus among the 18 readers on the presence of blood and/or contrast. However, intra-rater global agreement across all 18 physicians was relatively high, with a median kappa value of 0.675. This intra-rater consistency was seen across all specialties, regardless of level of training.Conclusion: Physician judgment for the presence of blood and/or contrast on day-1 post-thrombectomy non-contrast CT scan shows limited inter-observer reliability. Advanced imaging modalities may then be warranted for challenging clinical cases.

Objectives: To assess whether performing a pre-intervention gadolinium-enhanced extracranial magnetic resonance angiogram (MRA) in addition to intracranial vascular imaging is associated with improved thrombectomy time metrics.Methods: Consecutive patients treated by MT at a large comprehensive stroke center between January 2012 and December 2017 who were screened using pre-intervention MRI were included. Patients characteristics and procedural data were collected. Univariate and multivariate analysis were performed to compare MT speed, efficacy, complications, and clinical outcomes between patients with and without pre-intervention gadolinium-enhanced extracranial MRA.Results: A total of 912 patients were treated within the study period, including 288 (31.6%) patients with and 624 (68.4%) patients without extracranial MRA. Multivariate analysis showed no significant difference between groups in groin puncture to clot contact time (RR = 0.93 [0.85–1.02], p = 0.14) or to recanalization time (RR = 0.92 [0.83–1.03], p = 0.15), rates of successful recanalization (defined as a mTICI 2b or 3, RR = 0.93 [0.62–1.42], p = 0.74), procedural complications (RR = 0.81 [0.51–1.27], p = 0.36), and good clinical outcome (defined by a mRS ≤ 2 at 3 months follow-up, RR = 1.05 [0.73–1.52], p = 0.79).Conclusion: Performing a pre-intervention gadolinium-enhanced extracranial MRA in addition to non-contrast intracranial MRA at stroke onset does not seem to be associated with a delay or shortening of procedure times.