Potential for the use of the Solitaire stent for recanalization of middle cerebral artery occlusion without a susceptibility vessel sign

Susceptibility weighted imaging for detection of thrombus in acute ischemic stroke: A cross-sectional study

Background and Aims

Susceptibility-weighted imaging (SWI) can help in the diagnosis of thrombus within the vessel in acute ischemic stroke, known as susceptibility vessel sign (SVS), and detection of SVS within the vessel can predict treatment modality and outcome. In this study, the purpose is to correlate the SVS on SWI with different parameters of stroke.

Methods

This prospective cross-sectional study enrolled consecutive stroke patients with vessel occlusion on magnetic resonance angiography (MRA) over 1 year. The relationship between SVS on SWI with risk factors, territory involved, and length of thrombus was correlated with the National Institutes of Health Stroke Scale (NIHSS).

Results

A total of 105 patients were enrolled in this study. Sixty-two percent (66 out of 105) of patients showed SVS on SWI with MRA-positive occlusion. A positive correlation was observed between SVS on SWI and the risk factor (p = 0.003, chi-square test), with 86% of patients with heart disease and 47% with hypertension exhibiting SVS. Additionally, a positive correlation was observed between SVS on SWI and territorial occlusion (p = 0.000, chi-square test). A moderate positive correlation was observed between the NIHSS and thrombus length (p = 0.002, Pearson's correlation coefficient), with a Pearson's coefficient of 0.367.

Conclusions

SWI can be useful in identifying the location of the thrombus, and NIHSS can determine the thrombus length in acute stroke. A higher incidence of SVS can be associated with risk factors, and it also depends upon the site of occlusion of the vessel.

Negative susceptibility vessel sign might be predictive of complete reperfusion in patients with acute basilar artery occlusion managed with thrombectomy

OBJECTIVES

Negative susceptibility vessel sign (SVS) on pre-thrombectomy MRI has been linked to fibrin-rich thrombus and difficult retrieval in anterior ischemic stroke. However, its impact in posterior circulation-large vessel occlusion stroke (PC-LVOS) has not yet been elucidated. We aim to investigate the relationship of SVS parameters with stroke subtypes and their influence on angiographic and functional outcomes.

METHODS

Prospective thrombectomy registries at two-comprehensive stroke centers were retrospectively reviewed between January 2015 and December 2019 for consecutive MRI-selected patients with PC-LVOS. Two groups were assigned by two independent readers, based on the presence or absence of the SVS (SVS +, SVS -) on MRI-GRE sequence. Multivariate logistic regression analysis was utilized to study primarily the impact of the SVS on the rate of complete recanalization (defined as mTICI 2c/3) at the final series following endovascular thrombectomy (EVT) and whether or not it might influence the efficacy of the frontline EVT strategy. Secondarily, we studied whether the absence of the SVS was predictive of the rate of 90-day functional independence (defined as mRS score < 2). Lastly, both qualitative (SVS +, SVS-) and quantitative (SVS length and diameter) parameters of the SVS were analyzed in association with the puncture to recanalization interval and various stroke etiological subtypes based on TOAST criteria.

RESULTS

Among 1823 patients, 116 were qualified for final analysis (median age, 68 (59-75) years; male, 65%); SVS was detected in 62.9% (73/116) of cases. SVS length was an independent predictor of procedural duration (p = .01) whilst two-layered SVS was inversely associated with the atherosclerosis etiological subtype (aOR = 0.27, 95% CI 0.08-0.89; p = .03). Successful recanalization was achieved in 82% (60/73) vs. 86% (37/43), p = .80 of patients with SVS (+, -) respectively. Only in SVS (+), stentriever (RR 0.59 (0.4-0.88), p = .009), and contact-aspiration (RR 0.82 (0.7-0.96), p = .01) achieved a lower rate of successful recanalization compared to combined technique. SVS (-) was significantly associated with a higher rate of mTICI 2c/3 (aOR = 4.444; 95% CI 1.466-13.473; p = .008) and showed an indirect effect of 9% towards functional independence mediated by mTICI 2c/3.

CONCLUSION

SVS parameters in PC-LVOS might predict stroke subtype and indirectly influence the functional outcome by virtue of complete recanalization.

KEY POINTS

• Negative susceptibility vessel sign (SVS) in patients with basilar occlusion independently predict complete recanalization that indirectly instigated a 3-month favorable outcome following thrombectomy. • The longer the SVS, the higher likelihood of large artery atherosclerosis and the longer the thrombectomy procedure. • Two-layered SVS might be negatively associated with the presence of atherosclerosis, yet already-known limitations of TOAST classification and the absence of pathological analysis should be taken into consideration.

Selecting the Appropriate First-Line Strategy Based on Hyperdense Vessel Sign in Acute Ischemic Stroke Increases First Pass Recanalization: A Tertiary Center Experience

Background:  The data pertaining to selecting an optimal first-line strategy (stent retriever [SR] vs. contact aspiration [CA]) based on noncontrast computed tomography (NCCT) in cases of acute ischemic stroke consequent to large vessel occlusion (LVO) is lacking.

Aims:  This article studies the influence of hyperdense vessel sign (HVS) in selecting optimal first-line strategy, with intention of increasing first-pass recanalization (FPR).

Methods:  Upfront approach at our center is SR technique with rescue therapy (CA) adoption consequent to three failed SR attempts to achieve successful recanalization. Data of patients with acute LVO who underwent mechanical thrombectomy from June 2017 to May 2020 was retrospectively analyzed. Patients were classified into HVS (+) and HVS (−) cohort. Rate of successful recanalization (first pass, early, and final) and efficacy of rescue therapy was assessed between the two cohorts.

Results:  Of 52 patients included, 28 and 24 were assigned to the HVS (+) and HVS (−) cohort, respectively. FPR was observed in 50% of HVS (+) and 20.9% of HVS (−) ( p  = 0.029). Early recanalization was documented in 64.2% of HVS (+) and 37.5% of HVS (−) ( p  = 0.054). Rescue therapy need was higher in patients not demonstrating HVS ( p  = 0.062). Successful recanalization was achieved with rescue therapy in 50% of HVS (−) group.

Conclusion:  A higher FPR is achievable following individualized first-pass strategy (based on NCCT appearance of clot), instead of a generalized SR first-pass approach. This CT imaging-based strategy is a step closer to achieving primary angiographic goal of FPR.

Solitaire AB stent-angioplasty for stenoses in perforator rich segments: A single-center experience

BACKGROUND

Vascular angioplasty and stenting of middle cerebral artery (MCA) and basilar artery (BA) stenoses are associated with poor clinical outcomes and high mortality rates thought to be related to the abundance of perforating arteries in those segments. This study explores the use of Solitaire AB as an off-label vascular stent to treat stenoses in the MCA and BA.

METHODS

Solitaire AB stents were placed during angioplasty and stenting of MCA and BA stenoses in patients at our department between January 2015 and May 2017 with 6-36 months follow-up. Operative results were assessed by follow-up angiography and transcranial doppler after the procedure. Neurologic status was evaluated before and after treatment according to the modified Ranking Scale (mRS).

RESULTS

A total of 32 patients were included in the study. Seventeen (53.12%) patients presented with MCA stenosis and 15 (46.87%) with BA stenosis. The 30-day rate of procedure-related complications was 3.1% (1/32). Post-stenting residual stenosis degrees ranged from 0% to 40% (mean 13.44% ± 10.66%). Mean degree of residual stenosis in 26 patients followed up by DSA was 8.64% ± 9.67%. The mRS 0-2 was achieved in all (100%) patients at 6-12 months post-procedure.

CONCLUSIONS

Our study indicates the off-label use of Solitaire AB for stenting is effective and safe for MCA and BA stenoses with high technical success and low complications. We recommend that lesion-specific therapy with an anatomically fitted stent design enables optimal treatment for intracranial stenosis.

Susceptibility Vessel Sign in the ASTER Trial: Higher Recanalization Rate and More Favourable Clinical Outcome after First Line Stent Retriever Compared to Contact Aspiration

Background and Purpose

In the Aspiration vs. Stent Retriever for Successful Revascularization (ASTER) trial, which evaluated contact aspiration (CA) versus stent retriever (SR) use as first-line technique, the impact of the susceptibility vessel sign (SVS) on magnetic resonance imaging (MRI) was studied to determine its influence on trial results.

Methods

We included patients having undergone CA or SR for M1 or M2 occlusions, who were screened by MRI with T2^* gradient recalled echo. Occlusions were classified as SVS (+) or SVS (–) in each randomization arm. Modified thrombolysis in cerebral infarction (mTICI) 2b, 2c, or 3 revascularization rates were recorded and clinical outcomes assessed by the overall distribution of modified Rankin scale (mRS) at 90 days.

Results

Among the 202 patients included, 143 patients were SVS (+) (70.8%; 95% confidence interval [CI], 64.5% to 77.1%). Overall, there was no difference in angiographic and clinical outcomes according to SVS status. However, compared to SR, CA achieved a lower mTICI 2c/3 rate in SVS (+) patients (risk ratio [RR] for CA vs. SR, 0.60; 95% CI, 0.51 to 0.71) but not in SVS (–) (RR, 1.11; 95% CI, 0.69 to 1.77; P for interaction=0.018). A significant heterogeneity in favor of superiority of first-line SR strategy in SVS (+) patients was also found regarding the overall mRS distribution (common odds ratio for CA vs. SR, 0.40 vs. 1.32; 95% CI, 0.21 to 0.74 in SVS (+) vs. 95% CI, 0.51 to 3.35 in SVS (–); P for interaction=0.038).

Conclusions

As a first line strategy, SR achieved higher recanalization rates and a more favourable clinical outcome at 3 months compared to CA when MRI shows SVS within the thrombus.

Susceptibility weighted imaging in acute cerebral ischemia: review of emerging technical concepts and clinical applications

Susceptibility weighted imaging (SWI) is an essential magnetic resonance imaging sequence in the assessment of acute ischemic stroke. In this article, we discuss the physics principals and clinical application of conventional SWI and multi-echo SWI sequences. We review the research evidence and practical approach of SWI in acute ischemic stroke by focusing on the detection and characterization of thromboembolism in the cerebral circulation. In addition, we discuss the role of SWI in the assessment of neuroparenchyma by depiction of asymmetric hypointense cortical veins in the ischemic territory (surrogate tissue perfusion), detection of existing microbleeds before stroke treatment and monitoring for hemorrhagic transformation post-treatment. In conclusion, the SWI sequence complements other parameters in the stroke magnetic resonance imaging protocol and understanding of the research evidence is vital for practising stroke neurologists and neuroradiologists.

Susceptibility Vessel Sign on MRI Predicts Favorable Clinical Outcome in Patients with Anterior Circulation Acute Stroke Treated with Mechanical Thrombectomy

BACKGROUND AND PURPOSE

The susceptibility vessel sign on MR imaging has been reported to indicate acute occlusion from erythrocyte-rich thrombus. The purpose of this study was to evaluate the influence of the susceptibility vessel sign seen on MR imaging before treatment on the clinical outcome after mechanical thrombectomy for anterior circulation acute stroke.

MATERIALS AND METHODS

We retrospectively included 73 consecutive patients who were treated for anterior circulation acute stroke by mechanical thrombectomy from December 2009 to September 2013. Each patient underwent MR imaging before mechanical thrombectomy. The presence (susceptibility vessel sign+) or absence of the susceptibility vessel sign (susceptibility vessel sign-) was recorded. Mechanical thrombectomy was performed either alone or in association with IV tPA according to the site and time after occlusion. Good functional outcome was defined by an mRS ≤ 2 at 3 months in susceptibility vessel sign+ and susceptibility vessel sign- groups. Patient clinical characteristics, initial NIHSS score and ASPECTS, site of occlusion, time between onset to groin puncture, TICI after mechanical thrombectomy, NIHSS score at day 1, and spontaneous hyperattenuation on CT at day 1 were also analyzed.

RESULTS

Fifty-three patients with susceptibility vessel sign+ and 20 with susceptibility vessel sign- were included in our study. mRS ≤ 2 at 3 months occurred in 65% patients in the susceptibility vessel sign+ group and 26% in the susceptibility vessel sign- group (P = .004). On multivariate analysis, the susceptibility vessel sign was the only parameter before treatment that could predict mRS ≤ 2 at 3 months (OR, 8.7; 95% CI, 1.1-69.4; P = .04).

CONCLUSIONS

Our study strongly suggests that the susceptibility vessel sign on MR imaging before treatment is predictive of favorable clinical outcome for patients presenting with anterior circulation acute stroke and treated with mechanical thrombectomy.

Diagnostic Value of Thrombus Size on T2(*)-weighted Gradient Echo Imaging in Acute Middle Cerebral Artery Occlusion

Objective

The T2^*-weighted gradient echo image susceptibility vessel sign (GRE SVS) is a well-known indicator of intraluminal thrombi in acute cerebral infarction. The purpose of this study was to evaluate the relationships between thrombus size on GRE SVS and recanalization after intravenous administration of tissue plasminogen activator (IV-tPA).

Materials and Methods

Fifty five patients with GRE SVSs on the M1 were enrolled. Examination of magnetic resonance image (MRI), including diffusion weighted imaging and MR angiography, was performed within 20 minutes of admission. Thrombus size on GRE was calculated using the Picture Archiving and Communication System upon initial MRI. Recanalization was assessed with follow-up MRI or transfemoral cerebral angiography within 24 hours of treatment.

Results

The patient group consisted of 37 males and 18 females with an average age of 63.74 ± 10.28 years (range: 43 - 77 years). The median NIHSS score was 13. Fifteen of these patients achieved recanalization (27.3%). The average thrombus cross-sectional area in the recanalization group was 38.54 ± 20.27 mm², and the corresponding size of the non-recanalization group was 53.38 ± 24.77 mm² (p = 0.043). In the receiver operator characteristic curve for thrombus cross-sectional area in relation to recanalization, the cut-off point was 47.28 mm². The sensitivity at this cut-off point was 73.3%, the specificity was 60%, and the area under the curve was 0.687.

Conclusion

Thrombus size on GRE is a simple diagnostic tool that can be easily measured, and thrombus size on GRE SVS was found to be associated with recanalization after IV-tPA.