Subarachnoid Contrast Accumulation and Alberta Stroke Program Early Computed Tomography Score Applied to Contrast Accumulation After Thrombectomy as Predictors of Symptomatic Hemorrhage

Machine learning, clinical-radiomics approach with HIM for hemorrhagic transformation prediction after thrombectomy and treatment

Background

This study aimed to develop a clinical-radiomics model using hyperattenuated imaging markers (HIM), characterized by hyperattenuation on head non-contrast computed tomography immediately after thrombectomy, to predict the risk of hemorrhagic transformation (HT) in patients undergoing endovascular mechanical thrombectomy (MT).

Methods

A total of 159 consecutive patients with HIM were screened immediately after MT for inclusion. The datasets were randomly divided into training and test cohorts at a ratio of 8:2. An optimal machine learning (ML) algorithm was used for model development. Subsequently, models for clinical, radiomics, and clinical-radiomics were developed. The performance of the models was measured using receiver operating characteristic (ROC) and decision curve analyses (DCA). The interpretability and predictor importance of the model were analyzed using Shapley additive explanations.

Results

Of the 159 patients, 100 (62.9%) exhibited HT. The support vector machine (SVM) was the optimal ML algorithm for constructing the models. In predicting HT, the areas under the curve (AUCs) of the clinical model were 0.918 (95% confidence interval [CI] = 0.869-0.966) in the training cohort and 0.854 (95% CI = 0.724-0.984) in the test cohort. The AUCs of the radiomics model were 0.869 (95% CI = 0.802-0.936) and 0.829 (95% CI = 0.668-0.990), while those of the clinical-radiomics model were 0.944 (95% CI = 0.905-0.984) and 0.925 (95% CI = 0.832-1.000).

Conclusion

The suggested clinical-radiomics model based on HIM is a reliable method that can provide a risk evaluation of HT in individuals undergoing MT.

Subarachnoid iodine leakage on dual-energy computed tomography after mechanical thrombectomy is associated with malignant brain edema

BACKGROUND

Dual-energy computed tomography (DE-CT) can differentiate between hemorrhage and iodine contrast medium leakage following mechanical thrombectomy (MT) for acute ischemic stroke (AIS). We determined whether subarachnoid hemorrhage (SAH) and subarachnoid iodine leakage (SAIL) on DE-CT following MT were associated with malignant brain edema (MBE).

METHODS

We analyzed the medical records of 81 consecutive anterior circulation AIS patients who underwent MT. SAH or SAIL was diagnosed via DE-CT performed immediately after MT. We compared the procedural data, infarct volumes, MBE, and modified Rankin scale 0-2 at 90 days between patients with and without SAH and between patients with and without SAIL. Furthermore, we evaluated the association between patient characteristics and MBE.

RESULTS

A total of 20 (25%) patients had SAH and 51 (63%) had SAIL. No difference in diffusion-weighted imaging (DWI)-infarct volume before MT was observed between patients with and without SAH or patients with and without SAIL. However, patients with SAIL had larger DWI-infarct volumes 1 day following MT than patients without SAIL (95 mL vs 29 mL; p=0.003). MBE occurred in 12 of 81 patients (15%); more patients with SAIL had MBE than patients without SAIL (22% vs 3%; p=0.027). Severe SAIL was significantly associated with MBE (OR, 12.5; 95% CI, 1.20-131; p=0.006), whereas SAH was not associated with MBE.

CONCLUSION

This study demonstrated that SAIL on DE-CT immediately after MT was associated with infarct volume expansion and MBE.

CT Texture-Based Nomogram in Ischemic Stroke to Differentiate Intracerebral Hemorrhage from Contrast Extravasation after Thrombectomy

INTRODUCTION

Post-thrombectomy intraparenchymal hyperdensity (PTIH) in patients with acute ischemic stroke is a common CT sign, making it difficult for physicians to distinguish intracerebral hemorrhage in the early post-thrombectomy period. The aim of this study was to develop an effective model to differentiate intracerebral hemorrhage from contrast extravasation in patients with PTIH.

METHODS

We retrospectively collected information on patients who underwent endovascular thrombectomy at two stroke centers between August 2017 and January 2023. A total of 222 patients were included in the study, including 118 patients in the development cohort, 52 patients in the internal validation cohort, and 52 patients in the external validation cohort. The nomogram was constructed using R software based on independent predictors derived from the multivariate logistic regression analysis, including clinical factors and CT texture features extracted from hyperdense areas on CT images. The performance and accuracy of the derived nomogram were assessed by the area under the receiver operating characteristic curve (AUC-ROC) and calibration curves. Additionally, decision curve analysis was conducted to appraise the clinical utility of the nomogram.

RESULTS

Our nomogram was derived from two clinical factors (ASPECT score and onset to reperfusion time) and two CT texture features (variance and uniformity), with AUC-ROC of 0.943, 0.930, and 0.937 in the development, internal validation, and external validation cohorts, respectively. Furthermore, the calibration plot exhibited a strong agreement between the predicted outcome and the actual outcome. In addition, the decision curve analysis revealed the clinical utility of the nomogram in accurately predicting hemorrhage in patients with PTIH.

CONCLUSION

The developed nomogram, based on clinical factors and CT texture features, proves to be effective in distinguishing intracerebral hemorrhage from contrast extravasation in patients with PTIH.

Predicting symptomatic intracranial hemorrhage in anterior circulation stroke patients with contrast enhancement after thrombectomy: the CAGA score

BACKGROUND

The aim of the study was to establish a reliable scoring tool to identify the probability of symptomatic intracranial hemorrhage (sICH) in anterior circulation stroke patients with contrast enhancement (CE) on brain non-contrast CT (NCCT) after endovascular thrombectomy (EVT).

METHODS

We retrospectively reviewed consecutive patients with acute ischemic stroke (AIS) who had CE on NCCT immediately after EVT for anterior circulation large vessel occlusion (LVO). We used the Alberta stroke program early CT score (ASPECTS) scoring system to estimate the extent and location of CE. Multivariable logistic regression was performed to derive an sICH predictive score. The discrimination and calibration of this score were assessed using the area under the receiver operator characteristic curve, calibration curve, and decision curve analysis.

RESULTS

In this study, 194 of 322 (60.25%) anterior circulation AIS-LVO patients had CE on NCCT. After excluding 85 patients, 109 patients were enrolled in the final analysis. In multivariate regression analysis, age ≥70 years (adjusted OR (aOR) 9.23, 95% CI 2.43 to 34.97, P＜0.05), atrial fibrillation (AF) (aOR 4.17, 95% CI 1.33 to 13.12, P＜0.05), serum glucose ≥11.1 mmol/L (aOR 9.39, 95% CI 2.74 to 32.14, P＜0.05), CE-ASPECTS ＜5 (aOR 3.95, 95% CI 1.30 to 12.04 P＜0.05), and CE at the internal capsule (aOR 3.45, 95% CI 1.03 to 11.59, P＜0.05) and M1 region (aOR 3.65, 95% CI 1.13 to 11.80, P＜0.05) were associated with sICH. These variables were incorporated as the CE-age-glucose-AF (CAGA) score. The CAGA score demonstrated good discrimination and calibration in this cohort, as well as the fivefold cross validation.

CONCLUSION

The CAGA score reliably predicted sICH in patients with CE on NCCT after EVT treatment.

NT-proBNP Levels and Collateral Circulation Status in Patients with Acute Ischemic Stroke

Methods

In this study, 326 hospitalized patients with acute anterior circulation ischemic stroke (AACIS) were included. A comparison of the clinical characteristics of those with and without AF was conducted. The Spearman rank correlation was used for the correlation analysis of plasma NT-proBNP level, regional leptomeningeal collateral (rLMC) score, and computed tomography perfusion (CTP) status in the AF and non-AF groups. An analysis of multivariate linear regression was used to determine how plasma NT-proBNP level, rLMC score, and CTP status influenced the score on the NIHSS.

Results

There was a greater plasma NT-proBNP level in the AF group compared with the non-AF group, an increased CTP volume (including CTP ischemic volume, CTP infarct core volume, and CTP ischemic penumbra volume (P = 0.002)), higher NIHSS score on admission, and lower rLMC score (P < 0.001 for the remaining parameters). A negative correlation exists between plasma NT-proBNP level and rLMC score (r = -0.156, P = 0.022), but a positive correlation exists between plasma NT-proBNP level and both CTP ischemic volume and CTP infarct core volume (r = 0.148, P = 0.003) in the AF group, but not in the non-AF group. Multivariate linear regression analysis demonstrated that NT-proBNP, CTP ischemic penumbra volume, and rLMC score were associated with NIHSS score, and NT-proBNP was positively associated with NIHSS scores (95% confidence interval (CI), 0.000-0.002; P = 0.004) in the AF group, whatever in the unadjusted model or adjusted models, but not in the nonlarge artery atherosclerosis (LAA) group.

Conclusion

In AACIS patients with AF, NT-proBNP level negatively correlated with collateral status, positively with CTP ischemic volume, and positively with NIHSS score.

Contrast enhancement by location and volume is associated with long-term outcome after thrombectomy in acute ischemic stroke

Contrast enhancement (CE) on brain non-contrast computed tomography (NCCT) is common after endovascular thrombectomy (EVT) in patients with acute ischemic stroke (AIS), but its association with clinical outcomes is not well established. The current study aimed to investigate this relationship. We retrospectively reviewed consecutive patients with acute ischemic stroke who had hyperdensity on NCCT immediately after EVT for anterior circulation large vessel occlusion (LVO) from January 2016 to December 2019. We used ASPECTS combined with volume measurement by 3D reconstruction to estimate the extent and location of CE. Multivariable regression analysis was conducted to explore the risk factors associated with clinical outcome. In this study, 113 of 158 (71.52%) anterior circulation AIS-LVO patients had hyperdensity on brain NCCT. After strict inclusion and exclusion criteria, a total of 64 patients were enrolled in the final analysis. In logistic regression analysis, CE-ASPECTS, CE volume, CE at the caudate nucleus, M4 and M6 region were associated with 3-month poor functional outcome after adjusting for confounding factors. The conventional variable model was used for reference, including age, initial NIHSS, the procedure time, stent retriever passes, recanalization status and baseline ASPECTS, with AUC of 0.73. When combined with the above-named variables (conventional variables + CE-ASPECTS + CE volume + CE at caudate nucleus + CE at M4 region + CE at M6 region), the predictive power was significantly improved, with AUC of 0.87 (95% CI 0.78-0.95). The spatial location and volume of CE on NCCT obtained immediately after EVT were independent and strong predictors for poor outcome at 3-months in patients with AIS after excluding definite hemorrhage by 24-h follow up CT.

Contrast extravasation and outcome of endovascular therapy in acute ischaemic stroke: a systematic review and meta-analysis

OBJECTIVE

Contrast extravasation (CE) after endovascular therapy (EVT) is commonly present in acute ischaemic stroke (AIS) patients. Substantial uncertainties remain about the relationship between CE and the outcomes of EVT in patients with AIS. Therefore, we aimed to evaluate this association.

DESIGN

A systematic review and meta-analysis of published studies were performed.

DATA SOURCE

We systematically searched the Medline and Embase databases for relevant clinical studies. The last literature search in databases was performed in June 2020.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

We included studies exploring the associations between CE and the outcomes of EVT in patients with AIS undergoing EVT.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted relevant information and data from each article independently. We pooled ORs with CIs using a random-effects meta-analysis to calculate the associations between CE and outcomes of EVT. The magnitude of heterogeneity between estimates was quantified with the I² statistic with 95% CIs.

RESULTS

Fifteen observational studies that enrolled 1897 patients were included. Patients with CE had higher risks of poor functional outcome at discharge (2.38, 95% CI 1.45 to 3.89 p=0.001; n=545) and poor functional outcome at 90 days (OR 2.16, 95% CI 1.20 to 3.90; n=1194). We found no association between CE and in-hospital mortality (OR 0.95, 95% CI 0.27 to 3.30; n=376) or 90-day mortality (OR 1.38, 95% CI 0.81 to 2.36; n=697) after EVT. Moreover, CE was associated with higher risks of post-EVT intracranial haemorrhage (ICH) (OR 6.68, 95% CI 3.51 to 12.70; n=1721) and symptomatic ICH (OR 3.26, 95% CI 1.97 to 5.40; n=1092).

CONCLUSIONS

This systematic review and meta-analysis indicates that in patients with AIS undergoing EVT, CE is associated with higher risks of unfavourable functional outcomes and ICH. Thus, we should pay more attention to CE in patients with AIS undergoing EVT.

Clinical Significance of Hyperdense Area after Endovascular Therapy in Patients with Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

OBJECTIVE

We performed a systematic review and meta-analysis to investigate the clinical significance of hyperdense area after thrombectomy in patients with acute ischemic stroke (AIS).

METHODS

We searched Ovid MEDLINE(R) and Epub Ahead of Print, In-Process and other Non-Indexed, Cochrane Library Clinical Controlled Trials and Embase from inception to September 2020 and collected the cohort and case-control studies about the clinical significance of hyperdense area on different types of computed tomography (CT) after thrombectomy in patients with AIS. Outcomes were poor functional outcome (modified Rankin Scale [mRS] Score 3-6 at discharge or 90-day), mortality and subtypes of hemorrhage according to the European Cooperative Acute Stroke Study (ECASS).

RESULTS

1,999 patients from 16 studies were included in this meta-analysis. Pooled results indicated higher risk of symptomatic intracerebral hemorrhage (odds ratio [OR] = 3.02; 95% confidence interval [CI] 1.84-4.95; p < 0.0001, I2 = 0%) in patients with hyperdense area, and the subtype of parenchymal hematoma as well. There was also higher odds of poor functional outcome based on the mRS 3-6 at discharge or 90-day (OR = 1.92; 95% CI 1.35-2.73; p = 0.0003, I2 = 31%) and mortality (OR = 2.06; 95% CI 1.41-3.02; p = 0.0002, I2 = 0%) in patients with hyperdense area after thrombectomy compared with those without hyperdense area.

CONCLUSIONS

Our results indicated that the presence of hyperdense area on CT after thrombectomy was associated with high risk of symptomatic intracerebral hemorrhage, poor functional outcome, as well as mortality in patients with AIS. However, further studies were needed to confirm these results. The meta-analysis was conducted in adherence with the PRISMA Statement and was registered at the International Prospective Register of Systematic Reviews (CRD42020164165). To the best of our knowledge, this study is the first meta-analysis investigating the effect of hyperdense area after endovascular therapy in patients with AIS.