Early Diffusion-Weighted Imaging Brain Stem Score for Acute Basilar Artery Occlusion Treated with Mechanical Thrombectomy

DWI-Based Radiomics Predicts the Functional Outcome of Endovascular Treatment in Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE

Endovascular treatment is a reference treatment for acute basilar artery occlusion (ABAO). However, no established and specific methods are available for the preoperative screening of patients with ABAO suitable for endovascular treatment. This study explores the potential value of DWI-based radiomics in predicting the functional outcomes of endovascular treatment in ABAO.

MATERIALS AND METHODS

Patients with ABAO treated with endovascular treatment from the BASILAR registry (91 patients in the training cohort) and the hospitals in the Northwest of China (31 patients for the external testing cohort) were included in this study. The Mann-Whitney U test, random forests algorithm, and least absolute shrinkage and selection operator were used to reduce the feature dimension. A machine learning model was developed on the basis of the training cohort to predict the prognosis of endovascular treatment. The performance of the model was evaluated on the independent external testing cohort.

RESULTS

A subset of radiomics features (n = 6) was used to predict the functional outcomes in patients with ABAO. The areas under the receiver operating characteristic curve of the radiomics model were 0.870 and 0.781 in the training cohort and testing cohort, respectively. The accuracy of the radiomics model was 77.4%, with a sensitivity of 78.9%, specificity of 75%, positive predictive value of 83.3%, and negative predictive value of 69.2% in the testing cohort.

CONCLUSIONS

DWI-based radiomics can predict the prognosis of endovascular treatment in patients with ABAO, hence allowing a potentially better selection of patients who are most likely to benefit from this treatment.

Endovascular Treatment for Posterior Circulation Stroke: Ways to Maximize Therapeutic Efficacy

The efficacy of endovascular treatment (EVT) in patients with posterior circulation stroke has not been proven. Two recent randomized controlled trials failed to show improved functional outcomes after EVT for posterior circulation stroke (PC-EVT). However, promising results for two additional randomized controlled trials have also been presented at a recent conference. Studies have shown that patients undergoing PC-EVT had a higher rate of futile recanalization than those undergoing EVT for anterior circulation stroke. These findings call for further identification of prognostic factors beyond recanalization. The significance of baseline clinical severity, infarct volume, collaterals, time metrics, core-penumbra mismatch, and methods to accurately measure these parameters are discussed. Furthermore, their interplay on EVT outcomes and the potential to individualize patient selection for PC-EVT are reviewed. We also discuss technical considerations for improving the treatment efficacy of PC-EVT.

Novel Diffusion-Weighted Imaging Score Showed Good Prognostic Value for Acute Basilar Artery Occlusion Following Endovascular Treatment: The Pons-Midbrain and Thalamus Score

BACKGROUND AND PURPOSE

Prognostic factors for outcome of endovascular treatment remains to be investigated in patients with acute basilar artery occlusion. We aimed to assess the prognostic value of a novel pretreatment diffusion-weighted imaging score: The Pons-Midbrain and Thalamus (PMT) score.

METHODS

Eligible patients who underwent endovascular treatment due to acute basilar artery occlusion were reviewed. The PMT score was a diffusion-weighted imaging-based semiquantitative scale in which the infarctions of pons, midbrain, and thalamus were fully considered. The PMT score was assessed as well as the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score and Brain Stem Score. Good outcomes were defined as a modified Rankin Scale score of ≤3 at 90-day and successful reperfusion as Thrombolysis in Cerebral Infarction grades 2b/3. The associations between baseline clinical parameters and good outcomes were evaluated with logistic regression.

RESULTS

A total of 107 patients with pretreatment magnetic resonance imaging were included in this cohort. The baseline PMT score (median [interquartile range], 3 [1-5] versus 7 [5-9]; P<0.001) and Brain Stem Score (median [interquartile range], 2 [1-4] versus 3 [2-5]; P=0.001) were significantly lower in good outcome group; the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score was higher in good outcome group without statistical significance. As a result of receiver operating characteristic curve analyses, the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score showed poor prognostic accuracy for good outcome (area under the curve, 0.60 [95% CI, 0.49-0.71]; P=0.081); The baseline PMT score showed significantly better prognostic accuracy for 90-day good outcome than the Brain Stem Score and National Institutes of Health Stroke Scale (area under the curve, 0.80 versus 0.68 versus 0.78, P=0.003). In addition, favorable PMT score <7 (odds ratio, 22.0 [95% CI, 6.0-80.8], P<0.001), Brain Stem Score <3 (odds ratio, 4.65 [95% CI, 2.05-10.55], P<0.001) and baseline National Institutes of Health Stroke Scale <23 (odds ratio, 8.0 [95% CI, 2.5-25.6], P<0.001) were associated with improved good outcome.

CONCLUSIONS

In patients with acute basilar artery occlusion following endovascular treatment, the pretreatment diffusion-weighted imaging based PMT score showed good prognostic value for clinical outcome.

Endovascular treatment of acute basilar artery occlusion: Outcomes, influencing factors and imaging characteristics from the Tama-REgistry of acute thrombectomy (TREAT) study

OBJECTIVE

The effectiveness of mechanical thrombectomy (MT) for acute basilar artery occlusion (ABAO) remains unknown. We evaluated the feasibility, safety, and efficacy of endovascular treatment for ABAO.

METHODS

We retrospectively investigated patients with ABAO who underwent MT using modern stent retrievers and an aspiration device between January 2015 and March 2019 at 12 comprehensive stroke centers. Functional outcomes and 90-day mortality rates were analyzed as primary outcomes. Factors influencing outcomes were analyzed as secondary outcomes. Relationships between outcome and affected area of infarction on arrival were also analyzed.

RESULTS

Seventy-three patients were included. Good outcome (modified Rankin Scale (mRS) score 0-2) was achieved in 25/73 patients (34.2%) and the all-cause 90-day mortality rate was 23.3% (17/73). Successful recanalization (modified Thrombolysis In Cerebral Infarction grade 2b and 3) was achieved in 70/73 patients (95.9%). In univariate analyses, age, National Institutes of Health Stroke Scale score, and posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) differed significantly between good and poor functional outcome groups. Age and pc-ASPECTS were significantly associated with functional outcomes in the logistic regression model. Positive findings for the midbrain on diffusion-weighted imaging on pc-ASPECTS and brainstem score were significantly associated with poor outcomes.

CONCLUSION

MT with modern devices for ABAO resulted in highly successful recanalization and good outcomes. A positive finding for the midbrain on initial imaging might predict poor outcomes. Further studies are required to confirm our results.

Age and discharge modified Rankin score are associated with 90-Day functional outcome after basilar artery occlusion treated with endovascular therapy

INTRODUCTION

Prognostic factors for functional outcome after basilar artery occlusion (BAO) treated with modern endovascular therapy (EVT) are sparse. We investigated the association between clinical characteristics, readily available imaging variables, and outcome in BAO patients treated with EVT.

METHODS

Retrospective analysis from a large healthcare system's prospectively collected code stroke registry of acute BAO patients treated with EVT between January 2017-January 2020. The primary outcome measure was a favorable 90-day modified Rankin score (mRS) of 0-2.

RESULTS

65 patients (median age 67 years, 57% male, median NIHSS 16) met the study inclusion criteria. Thrombolysis in Cerebral Infarction (TICI) 2 b-3 revascularization was achieved in 57/65 patients (88%) with a median time to revascularization of 445 minutes [IQR 302-840]. Ninety-day good outcome was seen in 35% (23/65) of patients. In a univariate analysis, age, history of ischemic stroke, baseline NIHSS, BAO site, and discharge mRS were associated with significant differences between the good and poor outcome groups. A multivariable logistic regression analysis demonstrated an independent association with 90-day good outcome and younger age (per 1-year, OR 0.79, 95% CI 0.64, 0.98) and good discharge mRS (0-2) (OR > 999.99, 95% CI 13.26, > 999.99).

CONCLUSIONS

Patients presenting with an acute BAO treated with modern EVT have a good 90-day outcome in over one-third of cases. Age and discharge mRS are independently associated with good 90-day outcome. Additional studies may focus on factors that can enhance discharge function after BAO, a novel prognostic indicator for favorable 90-day outcome in our study.

Predictors of Very Poor Outcome after Mechanical Thrombectomy for Acute Basilar Artery Occlusion

Prognosis for patients with acute basilar artery occlusion (BAO) remains poor. Successful revascularization is a main predictor of favorable clinical outcomes after mechanical thrombectomy for BAO. However, even if mechanical thrombectomy is successful, some patients have a poor clinical outcome, including vegetative state and mortality. This study investigated the factors that are predictive of extremely poor clinical outcomes despite successful revascularization after mechanical thrombectomy for BAO.

We evaluated 35 consecutive patients who presented with acute ischemic stroke due to BAO and who were successfully treated with mechanical thrombectomy. A very poor outcome was defined as a modified Rankin Scale (mRS) score of 5 or 6 at 3 months after treatment. The associations between the clinical, imaging, procedural factors, and poor outcome were evaluated.

Using univariate analyses, there were significant differences in the preoperative National Institute of Health Stroke Scale (NIHSS) score (22.0 ± 9.0 vs. 30.5 ± 4.3, p <0.001), and infarct volume in brain stem (0.11 ± 0.19 cc vs. 2.55 ± 1.56 cc, p <0.001) between the control and very poor outcome groups. In receiver operating characteristic (ROC) curve analysis, the area under ROC curve of infarct volume in brain stem was 0.891 to predict very poor outcome.

Preoperative infarct volume in brain stem is strong predictor for very poor outcome. The infarct volume in brain stem is useful for deciding treatment indications.

Predictive value on diffusion weighted imaging scores for basilar artery occlusion after endovascular treatment

PURPOSE

To assess the predictive value of three scoring systems based on diffusion weighted imaging in basilar artery occlusion patients after endovascular treatment.

METHODS

We analyzed clinical and radiological data of patients with basilar artery occlusion from January 2010 to June 2019, with modified Rankin Scale of 0-2 and 3-6 defined as favorable outcome and unfavorable outcome at three months. Diffusion weighted imaging posterior circulation ASPECTS Score (DWI pc-ASPECT Score), Renard diffusion weighted imaging Score, and diffusion weighted imaging Brainstem Score were used to evaluate the early ischemic changes.

RESULTS

There were a total of 88 basilar artery occlusion patients enrolled in the study after endovascular treatment, with 33 of them getting a favorable outcome. According to the analysis, the time from onset to puncture within 12 h (odds ratio: 4.34; 95% confidence interval: 1.55-12.16; P = 0.01), presence of collateral flow via PCoA (odds ratio: 0.31; 95%CI: 0.12-0.79; P = 0.01) or between PICA and SCA (odds ratio: 0.18; 95%CI: 0.07-0.47; P = 0.00), equal or less than 15 points on baseline NIHSS (area under the curve 0.79, 95% CI 0.69-0.89; sensitivity = 69.1%, specificity = 81.8%; P = 0.00), and equal or less than 1.5 points on diffusion weighted imaging Renard score (area under the curve 0.63, 95% CI 0.51-0.75; sensitivity = 83.6%, specificity = 39.4%; P = 0.046) were independently associated with favorable outcome.

CONCLUSIONS

Renard diffusion weighted imaging score may be an independent predictor of functional outcome in basilar artery occlusion patients after endovascular treatment.