The Predictive Value of Cerebral Veins on Hemorrhagic Transformation After Endovascular Treatment in Acute Ischemic Stroke Patients: Enhanced Insights From Venous Collateral Circulation Analysis Using Four-Dimensional CTA.

RATIONALE AND OBJECTIVES: A significant complication of endovascular treatment (EVT) is hemorrhagic transformation (HT), which can worsen the outcomes of patients with acute ischemic stroke (AIS). This study aimed to evaluate the predictive value of venous collateral circulation on HT in patients with AIS undergoing EVT. MATERIALS AND METHODS: We retrospectively analyzed 126 patients with AIS who received EVT. The four-dimensional computed tomography angiography-based venous collateral score (4D-VCS) and arterial collateral circulation score (4D-ACS) were used to assess venous and arterial collaterals, respectively. Significant variables were identified using the least absolute shrinkage and selection operator algorithm. Logistic regression analysis, receiver operating characteristic (ROC) analysis, and DeLong's test were conducted. RESULTS: HT occurred in 41.3% (52/126) of patients. Higher clot burden score (CBS; odds ratio [OR]: 0.82, 95% confidence interval [CI]: 0.71-0.95, p = 0.009), better arterial collateral circulation (OR: 0.59, 95% CI: 0.42-0.83, p = 0.003), and better venous collateral circulation (OR: 0.85, 95% CI: 0.73-0.97, p = 0.020) were significantly associated with reduced HT risk. The area under the curve (AUC) values for CBS, 4D-ACS, and 4D-VCS were 0.730, 0.772, and 0.795, respectively. Model 1 (4D-VCS+CBS) achieved AUC of 0.820, significantly improving over CBS alone (p = 0.0133). Model 2 (4D-VCS+4D-ACS) had an AUC of 0.829, significantly higher than 4D-ACS alone (p = 0.0271). Model 3 (4D-ACS+CBS) had an AUC of 0.790. Model 4 (4D-VCS+4D-ACS+CBS) showed highest AUC of 0.851. Significant correlations were found between 4D-VCS and ischemic core volume (r = -0.684, p < 0.001) and between 4D-VCS and mismatch ratio (r = 0.558, p < 0.001). CONCLUSION: Evaluating venous collateral circulation using 4D-VCS could improve HT risk prediction in patients with AIS after EVT. When combined with other predictors, 4D-VCS may potentially enhance diagnostic performance, which suggests the potential role of venous collateral circulation in predicting HT risk.

A novel method of carotid artery wall imaging: black-blood CT.

OBJECTIVES: To evaluate the application of black-blood CT (BBCT) in carotid artery wall imaging and its accuracy in disclosing stenosis rate and plaque burden of carotid artery. METHODS: A total of 110 patients underwent contrast-enhanced CT scan with two phases, and BBCT images were obtained using contrast-enhancement (CE)-boost technology. Two radiologists independently scored subjective image quality on black-blood computerized tomography (BBCT) images using a 4-point scale and then further analyzed plaque types. The artery stenosis rate on BBCT was measured and compared with CTA. The plaque burden on BBCT was compared with that on high-resolution intracranial vessel wall MR imaging (VW-MR imaging). The kappa value and intraclass correlation coefficient (ICC) were used for consistency analysis. The diagnostic accuracy of BBCT for stenosis rate and plaque burden greater than 50% was evaluated by AUC. RESULTS: The subjective image quality scores of BBCT had good consistency between the two readers (ICC = 0.836, p < 0.001). BBCT and CTA had a good consistency in the identification of stenosis rate (p < 0.001). There was good consistency between BBCT and VW-MR in diagnosis of plaque burden (p < 0.001). As for plaque burden over 50%, BBCT had good sensitivity (93.10%) and specificity (73.33%), with an AUC of 0.950 (95%CI 0.838-0.993). Compared with CTA, BBCT had higher consistency with VW-MR in disclosing low-density plaques and mixed plaques (ICC = 0.931 vs 0.858, p < 0.001). CONCLUSIONS: BBCT can not only display the carotid artery wall clearly but also accurately diagnose the stenosis rate and plaque burden of carotid artery. CLINICAL RELEVANCE STATEMENT: Black-blood CT, as a novel imaging technology, can assist clinicians and radiologists in better visualizing the structure of the vessel wall and plaques, especially for patients with contraindication to MRI. KEY POINTS: • Black-blood CT can clearly visualize the carotid artery wall and plaque burden. • Black-blood CT is superior to conventional CTA with more accurate diagnosis of the carotid stenosis rate and plaque burden features.

Network meta-analysis of first-line thrombectomy strategy for acute posterior circulation strokes: a preliminary evaluation for combined approach.

Objective: Thrombectomy may provide superior results compared to best medical care for acute posterior circulation strokes (PCS). Contact aspiration (CA), stent retriever (SR), and combined SR + CA (SRA) are commonly employed as first-line techniques. However, the optimal strategy and the role of SRA remain uncertain. Methods: Systematic searching was conducted in three databases (PubMed, Embase, and Cochrane). Network meta-analyzes were performed using random-effects models. The reperfusion and clinical outcomes were compared. Pooled outcomes were presented as odds ratios (OR) with 95% confidence intervals (CI). Rankograms with surface under the cumulative ranking curve (SUCRA) were calculated. Results: Seventeen studies were included, involving a total of 645 patients who received first-line CA, 850 patients who received SR, and 166 patients who received SRA. Regarding final recanalization outcomes, both first-line SRA (OR = 3.2, 95%CI 1.4-11.0) and CA (OR = 2.1, 95%CI 1.3-3.7) demonstrated superiority over SR in achieving successful reperfusion [modified Thrombolysis In Cerebral Infarction (mTICI) 2b-3], with values of SUCRA 91.1, 58.5, and 0.4%, respectively. In addition, first-line SRA showed an advantage in achieving final mTICI 2c/3 compared to CA (OR = 3.6, 95%CI 0.99-16.0) and SR (OR = 6.4, 95%CI 1.3-35.0), with SUCRA value of 98.0, 44.7, and 7.2%, respectively. Regarding reperfusion outcome after the first pass, SRA also achieved a higher rate of mTICI 3 than SR (OR = 4.1, 95%CI 1.3-14.0), while CA did not (SUCRA 97.4, 4.6, 48.0%). In terms of safety outcomes, first-line CA was associated with a lower incidence of symptomatic intracranial hemorrhage (sICH) compared to SR (OR = 0.38, 95%CI 0.1-1.0), whereas the SRA technique did not (SUCRA 15.6, 78.6, 55.9%). Regarding clinical prognosis, first-line CA achieved a higher proportion of functional independence (modified Rankin Scale (mRS) 0-2) at 90 days than SR (OR = 1.4, 95%CI 1.1-1.9), whereas SRA did not (SUCRA 90.5, 17.4, 42.1%). Conclusion: For acute PCS, a first-line CA strategy yielded better results in terms of final successful reperfusion and 90-day functional independence compared to SR. As the combined technique, first-line SRA was associated with superior first-pass and final reperfusion outcomes compared to SR. However, no significant difference was observed in functional independence achieved by first-line SRA compared to the other two strategies. Further high-quality studies are warranted.

Collateral Circulation and BNP in Predicting Outcome of Acute Ischemic Stroke Patients with Atherosclerotic versus Cardioembolic Cerebral Large-Vessel Occlusion Who Underwent Endovascular Treatment.

PURPOSE: The aim of this study was to verify the value of collateral circulation and B-type natriuretic peptide (BNP) in predicting clinical outcomes of patients with acute ischemic stroke (AIS) and their biomarker value for stroke subtypes before endovascular treatment (EVT). PATIENTS AND METHODS: In this retrospective study, 182 patients who underwent EVT for unilateral anterior circulation large-vessel occlusion between March 2016 and January 2022 were analyzed. The modified collateral circulation scoring system on four-dimensional computed tomography angiography (4D CTA-CS) was used to assess collateral status, and stroke subtypes were determined according to the TOAST classification criteria. Patients were divided into good (mRS ≤ 2) and poor outcome (mRS > 2) groups based on their modified Rankin Scale (mRS) score at 3 months. RESULTS: 4D CTA-CS was an independent predictor of the clinical outcome for all AIS patients (odds ratio = 0.253; 95% CI, 0.147-0.437; p < 0.001), CE stroke patients (odds ratio = 0.513; 95% CI, 0.280-0.939; p = 0.030), and LAA stroke patients (odds ratio = 0.148; 95% CI, 0.049-0.447; p = 0.001). The BNP was a biomarker for clinical outcome prediction in CE (odds ratio = 1.004; 95% CI, 1.001-1.008; p = 0.005) but not in LAA patients. Combined with BNP, 4D CTA-CS improved predictive values for clinical outcomes (p < 0.05). CONCLUSION: Collateral status and BNP could be used as independent predictors of clinical outcomes in AIS patients and could determine stroke subtypes (CE stroke or LAA stroke). In addition, the model of 4D CTA-CS combined with BNP was the most effective in predicting clinical outcomes compared with collateral status or BNP alone.

Venous collaterals in acute ischemic stroke patients after endovascular treatments: a novel scoring system using 4D computed tomography angiography.

Background: To establish a novel cortical venous collateral score based on four-dimensional computed tomography angiography (4D CTA) and to assess the relationship between the score and clinical outcomes in patients with acute ischemic stroke (AIS) after endovascular treatments (EVTs). Methods: This was a retrospective case-control study designed to evaluate all consecutive patients with large vessel occlusion in unilateral anterior circulation who underwent EVTs at a single institution. Two independent neuroradiologists evaluated venous collaterals using different venous collateral scores: a cortical venous collateral score based on 4D CTA (4D-VCS), the prognostic evaluation based on cortical vein score difference in stroke (PRECISE) score, and the cortical vein opacification score (COVES). Spearman correlation analysis was used to analyze the correlation of different venous collateral scoring systems with final infarct volume (FIV), modified Rankin Scale (mRS) score, and artery collateral score. Multivariate logistic regression analysis was used to identify the prognostic value of each model. The areas under the curve (AUC) of the receiver operating characteristic (ROC) curve of the 6 models were compared by the DeLong test. Results: A total of 107 patients were enrolled in the study. The AUC of 4D-VCS was 0.92 [95% confidence interval (CI): 0.85 to 0.96; P<0.0001]. The 4D-VCS was highly correlated with FIV (r=-0.615; 95% CI: -0.737 to -0.473; P<0.001), mRS score (r=-0.706; 95% CI: -0.789 to -0.602; P<0.001), and arterial collateral score (r=0.769; 95% CI: 0.678 to 0.838; P<0.001). There were statistically significant differences between model 1 (AUC, 0.89; 95% CI: 0.81 to 0.94) and model 2 (AUC, 0.94; 95% CI: 0.88 to 0.98) (P=0.025), model 1 (AUC, 0.89; 95% CI: 0.81 to 0.94) and model 3 (AUC, 0.93; 95% CI: 0.87 to 0.97) (P=0.045), model 1 (AUC, 0.89; 95% CI: 0.81 to 0.94) and model 6 (AUC, 0.95; 95% CI: 0.89 to 0.98) (P=0.011), and model 2 (AUC, 0.94; 95% CI: 0.88 to 0.98) and model 5 (AUC, 0.89; 95% CI: 0.82 to 0.94) (P=0.032). Conclusions: The findings of this study suggested that 4D-VCS, a novel measurement of venous enhancement based on 4D CTA, may be accurately used to identify AIS patients with high risk of poor clinical outcome after EVTs.

BNP on Admission Combined with Imaging Markers of Multimodal CT to Predict the Risk of Cardioembolic Stroke.

Background: The aim of the study was to find the potential roles of B-type natriuretic peptide (BNP) and imaging markers on distinguishing cardioembolic (CE) stroke from non-CE stroke, so as to provide useful information for making individualized endovascular treatment (EVT) plan for the patients with acute ischemic stroke (AIS). Methods: The patients with unilateral anterior circulation large vessel occlusion who underwent EVT between March 2016 and December 2021 were analyzed in this study, retrospectively. The risk factors, laboratory test indicators, imaging parameters, and other factors were compared between the CE group and non-CE group. Logistic regression was used to analyze the risk factors of CE stroke. ROC curves were used to assess the values of different parameters on distinguishing CE stroke from non-CE stroke. The relationships between BNP and imaging parameters were assessed using the Spearman correlation analysis. Results: 160 patients were enrolled in the study and divided into the CE group (n = 66) and non-CE group (n = 94). BNP (odds ratio (OR) = 1.004; 95% CI, 1.001-1.009; p = 0.038), MMR (OR = 0.736; 95% CI, 0.573-0.945; p = 0.016), NIHSS (OR = 1.150; 95% CI, 1.022-1.294; p = 0.020), and AF (OR = 556.968; 95% CI, 51.739-5995.765; p < 0.001) were the independent predictive factors of CE stroke. The area under the curve (AUC) of BNP and mismatch ratio (MMR) were 0.846 (95% CI (0.780-0.898), p < 0.001) and 0.636 (95% CI (0.633-0.779), p < 0.001), respectively. The cut-off value of BNP was 249.23 pg/mL with the sensitivity of 74.24% and the specificity of 82.98%. BNP combined with MMR improved the predictive value for CE stroke. The AUC of the combination was 0.858 with the sensitivity of 84.85% and the specificity of 73.40%. BNP was correlated with 4D CTA collateral score, MMR, clot burden score, final infarct volume, infarct core volume, and ischemic penumbra volume (all, p < 0.05). Conclusion: BNP on admission combined with MMR is valuable for the risk prediction of CE stroke, which will promote the further screening of the high-risk patients with CE stroke and provide more diagnostic information for clinicians.

Predictive Value of Different Computed Tomography Perfusion Software Regarding 90-Day Outcome of Acute Ischemic Stroke Patients After Endovascular Treatment: A Comparison With Magnetic Resonance Imaging.

OBJECTIVE: This study compared ischemic core and penumbra volumes obtained using different computed tomography perfusion (CTP) software and evaluated the predictive value of CTP and magnetic resonance imaging (MRI) results for 90-day outcomes. METHODS: In total, 105 acute ischemic stroke patients who underwent endovascular treatment from January 2016 to December 2020 were included. Patients were divided into good and poor outcome groups by a modified Rankin Scale score. Computed tomography perfusion core and penumbra volumes were obtained using OleaSphere and Vitrea software to assess the volumetric relationship with MRI using the Spearman correlation test, intraclass correlation coefficient (ICC), and Bland-Altman plot. Three multivariable models were developed: baseline variables with MRI infarct volume, baseline variables with OleaSphere core volume, and baseline variables with Vitrea core volume. The area under the receiver operating characteristic curve of the 3 models was compared using the DeLong test. RESULTS: Median core volumes were 27.5, 26.9, and 31.1 mL for OleaSphere, Vitrea, and MRI, respectively. There was substantial correlation and excellent agreement between OleaSphere and MRI core volume ( ρ = 0.84, P < 0.001; ICC = 0.84) and Vitrea and MRI core volume ( ρ = 0.80, P < 0.001; ICC = 0.83). The areas under curve for MRI volume, OleaSphere, and Vitrea were 0.86, 0.84, and 0.83, respectively. There were no significant differences ( P = 0.18) between the predictive value of the 3 models. CONCLUSIONS: Computed tomography perfusion core volumes showed substantial correlation and excellent agreement with MRI. There was no significant difference in the predictive value of the 3 models, suggesting that core volumes measured using CTP software can predict patient prognosis.

Histological composition behind CT-based thrombus density and perviousness in acute ischemic stroke.

BACKGROUND: Clot composition could impact recanalization outcomes of thrombectomy, and preoperative imaging markers may help know about the histological components of thrombus. METHODS: Consecutive patients who underwent thrombectomy from June 2017 to December 2019 were reviewed. The mean Hounsfield unit (HU) of thrombus (aHU) and contralateral artery (cHU) were recorded based on non-enhanced CT. The relative thrombus density was calculated (dHU=aHU-cHU). Hyperdense artery sign (HAS) was identified if dHU≥ 4HU. The clot perviousness was evaluated via thrombus attenuation increase (δHU) on contrast-enhanced CT compared to non-enhanced CT. Pervious clots were identified when δHU≥ 11HU. Tissue quantification for thrombus was based on Martius Scarlet Blue staining, using the Orbit Imaging Analysis Software. Spearman rank correlations was used to detect the association between imaging markers and clot composition. The differences in clinical characteristics were compared according to the presence of HAS or pervious clots. RESULTS: Fifty-three patients were included. The dHU was positively correlated with erythrocyte fractions (r = 0.337, p = 0.014), while there was no significant association between aHU and erythrocyte components (r = 0.146, p = 0.296). HAS (+) patients showed a comparable proportion of modified Thrombolysis In Cerebral Infarction (mTICI) 2b-3 (94.6% vs. 87.5%, p = 0.740) and modified Rankin Scale score (mRS) 0-2 (35.1% vs. 56.3%, p = 0.152) compared with those HAS (-). Forty-seven cases were available for the analysis of clot perviousness. Clot perviousness was negatively associated with platelet fractions (r = -0.577, p < 0.001). Patients with pervious clots also showed a comparable proportion of mTICI 2b-3 (86.2% vs. 100%, p = 0.283) and mRS 0-2 (37.9% vs. 50.0%, p = 0.416) compared with impervious clots. CONCLUSIONS: This study suggests that relative thrombus density was positively correlated with erythrocyte fractions, while clot perviousness showed a negative relationship with platelet components. Yet, the presence of HAS or pervious clots did not show significant associations with recanalization and clinical outcomes. The conclusions should be drawn with caution.

Preliminary Application of a Quantitative Collateral Assessment Method in Acute Ischemic Stroke Patients With Endovascular Treatments: A Single-Center Study.

Objectives: To develop an efficient and quantitative assessment of collateral circulation on time maximum intensity projection CT angiography (tMIP CTA) in patients with acute ischemic stroke (AIS). Methods: Eighty-one AIS patients who underwent one-stop CTA-CT perfusion (CTP) from February 2016 to October 2020 were retrospectively reviewed. Single-phase CTA (sCTA) and tMIP CTA were developed from CTP data. Ischemic core (IC) volume, ischemic penumbra volume, and mismatch ratio were calculated. The Tan scale was used for the qualitative evaluation of collateral based on sCTA and tMIP CTA. Quantitative collateral circulation (CCq) parameters were calculated semi-automatically with software by the ratio of the vascular volume (V) on both hemispheres, including tMIP CTA VCCq and sCTA VCCq. Spearman correlation analysis was used to analyze the correlation of collateral-related parameters with final infarct volume (FIV). ROC and multivariable regression analysis were calculated to compare the significance of the above parameters in clinical outcome evaluation. The analysis time of the observers was also compared. Results: tMIP CTA VCCq (r = 0.61, p < 0.01), IC volume (r = 0.66, p < 0.01), Tan score on tMIP CTA (r = 0.52, p < 0.01) and mismatch ratio (r = 0.60, p < 0.01) showed moderate negative correlations with FIV. tMIP CTA VCCq showed the best prognostic value for clinical outcome (AUC = 0.93, p < 0.001), and was an independent predictive factor of clinical outcome (OR = 0.14, p = 0.009). There was no difference in analysis time of tMIP CTA VCCq among observers (p = 0.079). Conclusion: The quantitative evaluation of collateral circulation on tMIP CTA is associated with clinical outcomes in AIS patients with endovascular treatments.

Identification of Predictors for Hemorrhagic Transformation in Patients with Acute Ischemic Stroke After Endovascular Therapy Using the Decision Tree Model.

PURPOSE: This study aimed to identify independent predictors for the risk of hemorrhagic transformation (HT) in arterial ischemic stroke (AIS) patients. METHODS: Consecutive patients with AIS due to large artery occlusion in the anterior circulation treated with mechanical thrombectomy (MT) were enrolled in a tertiary stroke center. Demographic and medical history data, admission lab results, and Circle of Willis (CoW) variations were collected from all patients. RESULTS: Altogether, 90 patients were included in this study; among them, 34 (37.8%) had HT after MT. The final pruned decision tree (DT) model consisted of collateral score and platelet to lymphocyte ratios (PLR) as predictors. Confusion matrix analysis showed that 82.2% (74/90) were correctly classified by the model (sensitivity, 79.4%; specificity, 83.9%). The area under the ROC curve (AUC) was 81.7%. The DT model demonstrated that participants with collateral scores of 2-4 had a 75.0% probability of HT. For participants with collateral scores of 0-1, if PLR at admission was <302, participants had a 13.0% probability of HT; otherwise, participants had an 75.0% probability of HT. The final adjusted multivariate logistic regression analysis indicated that collateral score 0-1 (OR, 10.186; 95% CI, 3.029-34.248; p < 0.001), PLR (OR, 1.005; 95% CI, 1.001-1.010; p = 0.040), and NIHSS at admission (OR, 1.106; 95% CI, 1.014-1.205; p = 0.022) could be used to predict HT. The AUC for the model was 0.855, with 83.3% (75/90) were correctly classified (sensitivity, 79.4%; specificity, 87.3%). Less patients with HT achieved independent outcomes (mRS, 0-2) in 90 days (20.6% vs. 64.3%, p < 0.001). Rate of poor outcomes (mRS, 4-6) was significantly higher in patients with HT (73.5% vs. 19.6%; p < 0.001). CONCLUSION: Both the DT model and multivariate logistic regression model confirmed that the lower collateral status and the higher PLR were significantly associated with an increased risk for HT in AIS patients after MT. PLR may be one of the cost-effective and practical predictors for HT. Further prospective multicenter studies are needed to validate our findings.

Risk of secondary embolism events during mechanical thrombectomy for acute ischemic stroke: A single-center study based on histological analysis.

OBJECTIVE: Secondary embolism (SE) is a common adverse event during mechanical thrombectomy (MT) for acute intracranial large vessel occlusion, which could lead to incomplete revascularization and increased maneuvers. However, the mechanisms behind SE are still unclear. In this study, we aimed to investigate the risk factors of SE, with a focus on clot composition. PATIENTS AND METHODS: Consecutive patients with retrieved clots were reviewed. Histologic examination for thrombus included Hematoxylin and eosin, Martius Scarlet Blue, immunohistochemistry for von Willebrand factor (VWF). Patients included were assigned to SE or no SE group. The differences in histological composition and clinical characteristics were compared, and logistic regression was conducted for predictors of SE. RESULTS: Fifty-four patients were included, of which 19 were identified as having an SE. For patients with SE, there was more history of stroke or transient cerebral ischemia (TIA) (57.9 % vs. 28.6 %, p = 0.035), more occlusion located in terminal internal carotid artery (ICA) (63.2 % vs. 25.7 %, p = 0.007), relatively more contact aspiration used as frontline strategy (68.4 % vs. 45.7 %, p = 0.110), and less eTICI2c-3 recanalization achieved (52.6 % vs. 91.4 %, p = 0.003). As for histologic composition, the clots in SE group showed a higher proportion of erythrocyte fractions (42.9 % vs. 26.8 %, p = 0.045), while the other components were comparable with the non-SE group. Multivariate analysis suggested that a history of stroke or TIA (OR 6.45, 95 %CI 1.41-29.44, p = 0.016) and ICA occlusion (OR 8.05, 95 %CI 1.80-36.10, p = 0.006) could independently predict SE. CONCLUSION: History of TIA or stroke and occlusion in the terminal ICA were found to be independent predictors for SE. Thrombus with a higher erythrocyte fractions might be more fragile. Further studies are needed.

Collateral Vessels on 4D CTA as a Predictor of Hemorrhage Transformation After Endovascular Treatments in Patients With Acute Ischemic Stroke: A Single-Center Study.

Objective: Although the benefits of good collateral circulation on infarct volume and outcomes have been confirmed in previous studies, few studies have investigated the relationship between hemorrhagic transformation (HT) and collateral circulation in acute ischemic stroke (AIS). This study aimed to assess whether collateral circulation is an essential factor of HT after endovascular treatments (EVTs). Methods: In total, 71 consecutive AIS patients who underwent EVTs between July 2015 and February 2019 were retrospectively studied. The correlations among HT, collateral vessels on 4D CT angiography (4D CTA), and other predictive factors for HT [e.g., National Institutes of Health Stroke Scale (NIHSS) score, age, sex, serum glucose, and atrial fibrillation history] were evaluated by logistic regression analysis. Results: The rate of hemorrhagic transformation was 42.3% (30/71) in AIS patients. Multivariate logistic regression showed that a good collateral status (OR 0.76, 95% CI 0.73-0.80) was associated with a lower risk of HT. History of atrial fibrillation (OR 2.35, 95% CI 1.96-2.82), baseline NIHSS scores (OR 2.00, 95% CI 1.72-2.32), and higher serum glucose levels (OR 1.70, 95% CI 1.57-1.85) were all independent risk factors of HT. Conclusions: Patients with poor collateral circulation are at a higher risk of HT after receiving endovascular therapy. Thus, variations in collateral circulation based on 4D CTA may be an important factor for personalized clinical treatments. In addition, high blood glucose, atrial fibrillation and the baseline NIHSS score are all important independent predictors of HT.

Evaluation of Intracranial Vascular Status in Patients with Acute Ischemic Stroke by Time Maximum Intensity Projection CT Angiography: A Preliminary Study.

RATIONALE AND OBJECTIVES: To describe the application of time maximum intensity projection CTA (t-MIP CTA) in acute ischemic stroke and compare t-MIP CTA and single-phase CTA (sCTA) in assessing collateral circulation and predicting prognosis. MATERIALS AND METHODS: Twenty-nine acute ischemic stroke patients who underwent one-stop CT angiography (CTA)-CT perfusion scan were reviewed retrospectively. sCTA and t-MIP CTA were developed by CT perfusion scanning data. Image quality and collateral circulation were compared between the sCTA and t-MIP CTA groups. CT attenuation values, image noise, signal to noise , contrast to noise, and subjective image quality were obtained and compared between these two groups. The correlations of clinical prognosis and infarct volume with collateral status on t-MIP CTA and sCTA were analyzed, separately. Receiver operating characteristic curve was used to reveal the sensitivity and specificity of t-MIP CTA and sCTA in predicting outcome. RESULTS: All images exhibited good quality for diagnosis. In objective evaluation, the noise level of t-MIP CTA was significantly lower than that of sCTA (p < 0.001). Vascular attenuation (signal to noise and contrast to noise) of t-MIP were higher than those of sCTA (all, p < 0.001). The collateral status on t-MIP CTA and sCTA were both negatively correlated with modified Rankin Scale scores (t-MIP CTA, r = -0.709, p < 0.001; sCTA, r = -0.551, p = 0.024) and the final infarction volume (t-MIP CTA, r = -0.716, p = 0.001; sCTA, r = -0.629, p = 0.003). t-MIP CTA was better for predicting prognosis (AUC, 0.956; sensitivity, 0.917; specificity, 0.941; p < 0.001) than sCTA (AUC, 0.824; sensitivity, 0.500; specificity, 0.941; p = 0.003). CONCLUSION: In comparison with sCTA, t-MIP images showed higher image quality of intracranial vascularity and MIP could reveal vascular occlusion and evaluate collateral circulation more accurately. It was speculated that t-MIP could predict the prognosis more precisely.

Association Between Thrombus Density and Reperfusion Outcomes Using Different Thrombectomy Strategies: A Single-Center Study and Meta-Analysis.

Background: For patients with acute ischemic stroke (AIS), the thrombus density on non-enhanced CT (NECT) indicates the composition of the thrombus, a characteristic that impacts the efficacy of mechanical thrombectomy (MT). A previous meta-analysis suggested a correlation between higher thrombus density and successful reperfusion, but some new studies have drawn different conclusions. This single-center study and meta-analysis aimed to detect the association between thrombus density and reperfusion outcomes based on various thrombectomy strategies. Methods: We reviewed AIS patients who underwent MT at our center between July 2015 and May 2019. Thrombus density was recorded as mean Hounsfield Unit (HU) value on 1-mm reconstructed NECT, and expanded Thrombolysis In Cerebral Infarction (eTICI) scale was used to evaluate the reperfusion grade. The difference in thrombus density was examined according to reperfusion outcomes. Then, we systematically searched relevant literature on this issue. The random effect model was used to calculate standardized mean difference (SMD), and subgroup analysis was conducted according to MT strategies employed, including stent retriever (SR), contact aspiration (CA), Solumbra (a combination of SR and aspiration), and multiple thrombectomy modalities. Results: Sixty-four patients with anterior circulation AIS were included in our single-center study with 57 (89.1%) achieving successful reperfusion (eTICI2b-3). Retrospective analysis showed no significant difference in thrombus density between eTICI2b-3 and eTICI0-2a reperfusion (65.27 vs. 62.19, p = 0.462). As for systematic review, 11 studies were included in qualitative analysis, among which 6 had data available for meta-analysis. Pooled result showed that a comparable thrombus density between eTICI2b-3 and eTICI0-2a reperfusion (SMD 0.14, 95%CI -0.28 to 0.57, p = 0.50). Interestingly, in the SR subgroup, eTICI2b-3 reperfusion showed a significant higher thrombus density (SMD 0.53, 95%CI 0.10 to 0.96, p = 0.02), while an inverse trend was observed in the CA subgroup (SMD -0.48, 95%CI -0.88 to -0.07, p = 0.02). Conclusions: Although the pooled result of meta-analysis did not show a significant association between thrombus density and successful reperfusion, subgroup analysis implicated that the SR technique might be prone to retrieve high-density thrombus, while the CA subgroup showed an opposite tendency. Further studies are needed to confirm these results and to investigate its role in the optimization of thrombectomy strategy.

CT-based Higher Thrombus Density is associated with Secondary Embolism during Mechanical Thrombectomy: A Preliminary Observation.

BACKGROUND: Secondary embolism (SE) during mechanical thrombectomy (MT) for acute ischemic stroke (AIS) is the main reason for incomplete recanalization, while its risk factors are largely unknown. This study addresses a potential relationship between thrombus density on preinterventional computed tomography (CT) and the occurrence of SE. METHODS: We reviewed anterior circulation AIS patients who underwent MT from July 2015 to January 2019 in our center. Thrombus density was measured in Hounsfield Units (HU) on 1-mm and 5-mm preinterventional nonenhanced CT (NECT). Thrombus density, baseline characteristics, procedural, and clinical outcomes were compared between patients with SE and those without SE. Logistic regression was conducted to identified potential risk factors of SE. RESULTS: Sixty-four consecutively patients were included, of whom SE was identified in 16 (25.0%) patients. Compared with those without SE, patients with SE showed a higher thrombus density on both 1-mm (72.85 versus 64.28, P = .005) and 5-mm NECT (60.31 versus 49.71, P < .001), a higher proportion of atrial fibrillation (75.0% versus 45.8%, P = .043), a lower clot burden score (.5 versus 6.0, P = .029), and a higher proportion of front-line contact aspiration strategy (50.0% versus 16.7%, P = .020). Multivariate regression analysis showed that only thrombus density was the independent predictor of SE (for the model including HU values on 1-mm NECT, OR 1.11, 95%CI 1.01-1.23, P = .029; for the model including HU values on 5-mm NECT, OR 1.09, 95%CI 1.02-1.17, P = .018). CONCLUSIONS: Higher thrombus density was the independent predictor for SE. Further studies are needed to investigate its role in the optimization of thrombectomy strategy.

Improving Prognostic Evaluation by 4D CTA for Endovascular Treatment in Acute Ischemic Stroke Patients: A Preliminary Study.

OBJECTIVE: We aim to use 4D CTA with a comprehensive and objective scoring system to assess collateral circulation, and explore the value of prognosis prediction in endovascular treated patients. METHODS: Thirty-four patients with unilateral anterior circulation large vessels occlusion were reviewed in this study retrospectively. Single-phase CTA (sCTA) and 4D CTA acquired by CT perfusion scanning were analyzed for collateral circulation assessment. The collateral vessels were scored 0-4 according to modified collateral circulation scoring based on 4D CTA. Zero to two points indicated poor collateral circulation; 3-4 points indicated good collateral circulation. Good prognosis was defined as modified Rankin scale score of 0-2. Logistic regression was used to analyze the relationship between collateral circulation and prognosis. RESULTS: The mean age was 71.1 ± 11.5 years old. Collateral circulation on 4D CTA was an independent factor for predicting the prognosis (odds ratio = .101; 95% confidence interval: [.101-.924]; P = .042), but sCTA could not predict prognosis (P = .214). 4D CTA collateral circulation scoring had a good predicting efficacy on clinical prognosis (Area Under Curve (AUC) = .936; 95% confidence interval: [.751-.992], P < .005). Patients with good collaterals (4D CTA scores of 3-4) could obtain benefit from endovascular treatment (P = .029) compared with patients with poor collaterals (P = 1.000). CONCLUSIONS: 4D CTA could be applied to effectively evaluate cerebral collateral status. The accurate assessment of collateral circulation based on 4D CTA would be helpful to make medical decisions, especially for those patients who would undergo endovascular interventional treatment.