DWI-Based Algorithm to Predict Disability in Patients Treated with Thrombectomy for Acute Stroke.

BACKGROUND AND PURPOSE: The reasons for poor clinical outcome after thrombectomy for acute stroke, concerning around half of all patients, are misunderstood. We developed a hierarchic algorithm based on DWI to better identify patients at high risk of disability. MATERIALS AND METHODS: Our single-center, retrospective study included consecutive patients with acute ischemic stroke who underwent thrombectomy for large anterior artery occlusion and underwent pretreatment DWI. The primary outcome was the mRS at 3 months after stroke onset. Multivariable regression was used to identify independent clinical and imaging predictors of poor prognosis (mRS > 2) at 3 months, and a hierarchic algorithm predictive of disability was developed. RESULTS: A total of 149 patients were analyzed. In decreasing importance, DWI lesion volume of >80 mL, baseline NIHSS score of >14, age older than 75 years, and time from stroke onset to groin puncture of >4 hours were independent predictors of poor prognosis. The predictive hierarchic algorithm developed from the multivariate analysis predicted the risk of disability at 3 months for up to 100% of patients with a high predictive value. The area under the receiver operating characteristic curve was 0.87. CONCLUSIONS: The DWI-based hierarchic algorithm we developed is highly predictive of disability at 3 months after thrombectomy and is easy to use in routine practice.

Multicenter initial experience with the EmboTrap device in acute anterior ischemic stroke.

BACKGROUND AND PURPOSE: Mechanical thrombectomy predominantly using stent retrievers effectively restores cerebral blood flow and improves functional outcomes in patients with acute ischemic stroke. We sought to determine the safety and efficacy of mechanical thrombectomy using the EmboTrap device. MATERIALS AND METHODS: We identified 80 consecutive patients from 4 centers with acute ischemic stroke treated with EmboTrap from June 2015 to December 2016. All patients had confirmed large vessel occlusions in the anterior circulation using CT or MR angiography with salvageable tissue. We assessed baseline characteristics and treatment related parameters including onset-to-treatment time, recanalization success (mTICI 2b or greater), complications, and good clinical outcome (mRS 0 to 2). RESULTS: Successful recanalization was achieved in 72 patients (90%). When considering the use of a second thrombectomy device as failure, the EmboTrap successfully recanalized 65 patients (81%), with complete (mTICI 3) recanalization in 40 patients (50%) within 1 or 2 passes. Median procedure time (groin to recanalization) was 35 minutes (8-161 minutes). During the procedure, distal emboli in previously unaffected territories were found in 5 (6%) patients. There were 3 vasospasms (4%) and no vessel perforations. Intracranial hemorrhage on CT at day 1 was found in 18 17 (2321%) patients, none with subarachnoid hemorrhages, and 5 were symptomatic (6%). Good clinical outcome occurred in 4749/68 78 patients (6963%). CONCLUSIONS: In this multicenter retrospective study, the EmboTrap device achieved high recanalization rates, good clinical outcomes and was safe in treating acute stroke patients with large vessel occlusions.

The learning curve effect on embolization of cerebral dural arteriovenous fistula single-center experience in 48 consecutive patients.

BACKGROUND: Cerebral dural arteriovenous fistulas (DAVFs) are rare intracranial vascular lesions but can cause significant morbidity and mortality. OBJECTIVES: To analyze the effect of the center's experience on DAVF embolization efficacy and safety. METHODS: From May 2008 to October 2014, 57 embolization procedures were attempted on 48 patients (37 men and 11 women; median age: 63.9 years) for DAVF in a single center. DAVF presented with cortical venous reflux in 44/48 cases (91.7%) and hemorrhagic manifestation in 21/48 cases (43.75%). Angiographic occlusion quality, whether complete or incomplete (efficacy), and neurological complications (safety) were recorded. The patient population was divided into four consecutive quartiles during the inclusion period to assess the progress profile. Efficacy and safety outcomes were compared with Fisher's test. RESULTS: A logistic regression was performed to explore a learning curve phenomenon, showing a significant association between the chronological rank in the cohort and embolization efficacy (P=0.007). Significant differences were found between first and last quarter (P=0.036). The endovascular technique involved an arterial injection of Onyx® in 36/48 cases (75%), administered via the middle meningeal artery in 25/36 cases (69.5%). The complete occlusion rate improved significantly from 33.3% for the first quartile of the population, to 75.0% for the 2nd and 3rd quartiles and 83.3% for the last quartile. Neurological complications were found in 7/48 patients (14.6%), the rate decreased by 41.7% to 16.7%, without statistically difference. CONCLUSION: The efficacy and safety of DAVF embolization improved with the experience gained at the center, suggesting the existence of a learning curve.

WEB Treatment of Intracranial Aneurysms: Clinical and Anatomic Results in the French Observatory.

BACKGROUND AND PURPOSE: Flow disruption with the WEB device is a new technique for the endovascular treatment of wide-neck bifurcation aneurysms. To obtain precise data regarding the safety and efficacy of this treatment with high-quality methodology, the prospective French Observatory study was conducted. Analysis of these data is presented, including 1-year follow-up. MATERIALS AND METHODS: Patients with bifurcation aneurysms for which WEB treatment was indicated were included in this prospective, multicenter Good Clinical Practice study. Clinical data, including adverse events and clinical status at 1 month and 1 year, were collected and independently analyzed by a medical monitor. An independent core laboratory evaluated the anatomic results at 1 year following the procedure. RESULTS: Ten French neurointerventional centers included 62 patients (39 women), 33-74 years of age (mean, 56.6 ± 9.80 years) with 63 aneurysms. Aneurysm locations were the middle cerebral artery in 32 aneurysms (50.8%), anterior communicating artery in 16 (25.4%), basilar artery in 9 (14.3%), and internal carotid artery terminus in 6 (9.5%). Morbidity and mortality at 1 month were, respectively, 3.2% (2/62 patients) and 0.0% (0/62). Morbidity and mortality (unrelated to the treatment) at 1 year were, respectively, 0.0% (0/59) and 3.4% (2/59 patients). At 1 year, complete occlusion was observed in 30/58 aneurysms (51.7%); neck remnant, in 16/58 aneurysms (27.6%); and aneurysm remnant, in 12/58 aneurysms (20.7%). CONCLUSIONS: This prospective French Observatory study showed very good safety of aneurysm treatment with the WEB, with a high rate of adequate aneurysm occlusion at 1 year (79.3%).

Inter- and Intrarater Agreement on the Outcome of Endovascular Treatment of Aneurysms Using MRA.

BACKGROUND AND PURPOSE: Patients treated with coiling are often followed by MR angiography. Our objective was to assess the inter- and intraobserver agreement in diagnosing aneurysm remnants and recurrences by using multimodality imaging, including TOF MRA. MATERIALS AND METHODS: A portfolio composed of 120 selected images from 56 patients was sent to 15 neuroradiologists from 10 institutions. For each case, raters were asked to classify angiographic results (3 classes) of 2 studies (32 MRA-MRA and 24 DSA-MRA pairs) and to provide a final judgment regarding the presence of a recurrence (no, minor, major). Six raters were asked to independently review the portfolio twice. A second study, restricted to 4 raters having full access to all images, was designed to validate the results of the electronic survey. RESULTS: The proportion of cases judged to have a major recurrence varied between 16.1% and 71.4% (mean, 35.0% ± 12.7%). There was moderate agreement overall (κ = 0.474 ± 0.009), increasing to nearly substantial (κ = 0.581 ± 0.014) when the judgment was dichotomized (presence or absence of a major recurrence). Agreement on cases followed-up by MRA-MRA was similarly substantial (κ = 0.601 ± 0.018). The intrarater agreement varied between fair (κ = 0.257 ± 0.093) and substantial (κ= 0.699 ± 0.084), improving with a dichotomized judgment concerning MRA-MRA comparisons. Agreement was no better when raters had access to all images. CONCLUSIONS: There is an important variability in the assessment of angiographic outcomes of endovascular treatments. Agreement on the presence of a major recurrence when comparing 2 MRA studies or the MRA with the last catheter angiographic study can be substantial.

Endovascular treatment of wide-neck anterior communicating artery aneurysms using WEB-DL and WEB-SL: short-term results in a multicenter study.

BACKGROUND AND PURPOSE: Endovascular treatment of wide-neck anterior communicating artery aneurysms can often be challenging. The Woven EndoBridge (WEB) device is a recently developed intrasaccular flow disrupter dedicated to endovascular treatment of intracranial aneurysms. The aim of this study was to investigate the feasibility, safety, and efficacy of the WEB Dual-Layer and WEB Single-Layer devices for the treatment of wide-neck anterior communicating artery aneurysms. MATERIALS AND METHODS: Patients with anterior communicating artery aneurysms treated with the WEB device between June 2013 and March 2014 in 5 French centers were analyzed. Procedural success, technical complications, clinical outcome at 1 month, and immediate and 3- to 6-month angiographic follow-up results were analyzed. RESULTS: Ten patients with unruptured anterior communicating artery aneurysms with a mean neck diameter of 5.4 mm were treated with the WEB. Treatment failed in 3 of the 10 aneurysms without further clinical complications. One patient developed a procedural thromboembolic event, and the other 6 had normal neurologic examination findings at 1-month follow-up. Immediate anatomic outcome evaluation showed adequate occlusion (total occlusion or neck remnant) in 6 of 7 patients. Angiographic control was obtained in all patients, including 6 adequate aneurysm occlusions (3 complete occlusions and 3 neck remnants) at short-term follow-up. CONCLUSIONS: In our small series, treatment of wide-neck anterior communicating artery aneurysms with the WEB device was feasible and safe. However, patient selection based on the aneurysm and initial angiographic findings in the parent artery is important due to the limitations of the WEB device navigation.

Optimal MRI sequence for identifying occlusion location in acute stroke: which value of time-resolved contrast-enhanced MRA?

BACKGROUND AND PURPOSE: Identifying occlusion location is crucial for determining the optimal therapeutic strategy during the acute phase of ischemic stroke. The purpose of this study was to assess the diagnostic efficacy of MR imaging, including conventional sequences plus time-resolved contrast-enhanced MRA in comparison with DSA for identifying arterial occlusion location. MATERIALS AND METHODS: Thirty-two patients with 34 occlusion levels referred for thrombectomy during acute cerebral stroke events were consecutively included from August 2010 to December 2012. Before thrombectomy, we performed 3T MR imaging, including conventional 3D-TOF and gradient-echo T2 sequences, along with time-resolved contrast-enhanced MRA of the extra- and intracranial arteries. The 3D-TOF, gradient-echo T2, and time-resolved contrast-enhanced MRA results were consensually assessed by 2 neuroradiologists and compared with prethrombectomy DSA results in terms of occlusion location. The Wilcoxon test was used for statistical analysis to compare MR imaging sequences with DSA, and the κ coefficient was used to determine intermodality agreement. RESULTS: The occlusion level on the 3D-TOF and gradient-echo T2 images differed significantly from that of DSA (P < .001 and P = .002, respectively), while no significant difference was observed between DSA and time-resolved contrast-enhanced MRA (P = .125). κ coefficients for intermodality agreement with DSA (95% CI, percentage agreement) were 0.43 (0.3%-0.6; 62%), 0.32 (0.2%-0.5; 56%), and 0.81 (0.6%-1.0; 88%) for 3D-TOF, gradient-echo T2, and time-resolved contrast-enhanced MRA, respectively. CONCLUSIONS: The time-resolved contrast-enhanced MRA sequence proved reliable for identifying occlusion location in acute stroke with performance superior to that of 3D-TOF and gradient-echo T2 sequences.

WEB Treatment of Intracranial Aneurysms: Feasibility, Complications, and 1-Month Safety Results with the WEB DL and WEB SL/SLS in the French Observatory.

BACKGROUND AND PURPOSE: Safety analyses in the French Observatory have shown that treatment of intracranial aneurysms by using flow disruption with the Woven EndoBridge Device (WEB) is safe, with low morbidity and no mortality. The objective of this study was to analyze treatment feasibility, complications, and safety results in patients treated with the Woven EndoBridge Device Dual-Layer (WEB DL) and Woven EndoBridge Device Single-Layer/Single-Layer Sphere (WEB SL/SLS) in the French Observatory. MATERIALS AND METHODS: Patients with bifurcation aneurysms were included in this prospective, multicenter good clinical practices study. A medical monitor independently analyzed procedural and clinical data. The study started with the WEB DL, and secondarily, the WEB SL/SLS was authorized in the study. RESULTS: Between November 2012 and January 2014, 10 French centers included 62 patients with 63 aneurysms. Thirty patients with 31 aneurysms were treated with the WEB DL, and 32 patients with 32 aneurysms, with the WEB SL/SLS. The percentage of anterior communicating artery aneurysms treated with WEB SL/SLS was significantly higher (37.5%) compared with WEB DL (12.9%) (P = .04). The WEB SL/SLS was more frequently used in aneurysms of <10 mm than the WEB DL (respectively, 96.9% and 67.7%; P = .002). Morbidity was similar in both groups (WEB DL, 3.3%; WEB SL/SLS, 3.1%), and mortality was 0.0% in both groups. CONCLUSIONS: This comparative study shows increased use of WEB treatment in ruptured, small, and anterior communicating artery aneurysms when using WEB SL/SLS. There was a trend toward fewer thromboembolic complications with the WEB SL/SLS. With both the WEB DL and WEB SL/SLS, the treatment was safe, with low morbidity and no mortality.

One-year MR angiographic and clinical follow-up after intracranial mechanical thrombectomy using a stent retriever device.

BACKGROUND AND PURPOSE: Little is known about the consequences of arterial wall damage that may be due to mechanical endovascular thrombectomy. Our aim was to perform 1-year MR angiographic and clinical follow-up of patients treated with mechanical endovascular thrombectomy using the Solitaire device. MATERIALS AND METHODS: Patients with stroke treated between August 2010 and July 2012 were prospectively evaluated with a minimum follow-up of 1 year after mechanical endovascular thrombectomy. Angiographic follow-up was performed on a 3T MR imaging scanner and included intracranial artery TOF MRA and supra-aortic artery gadolinium-enhanced MRA. Images were assessed to detect arterial abnormalities (stenosis, occlusion, dilation) and were compared with the final post-mechanical endovascular thrombectomy run to differentiate delayed and pre-existing abnormalities. Clinical evaluation was performed with the mRS and the 36-Item Short-Form Health Survey questionnaire quality-of-life scale. RESULTS: Thirty-nine patients were angiographically assessed at the mean term of 19 ± 4 months. MRA showed intracranial artery abnormalities in 10 patients, including 5 delayed intracranial artery abnormalities in 4 patients (4 stenoses and 1 dilation), 4 cases of pre-existing intracranial artery stenosis, and 2 occlusions. Pre-existing etiologic cervical artery stenosis or occlusion was observed in 2 patients. All these patients remained asymptomatic during the follow-up period. A significant clinical improvement was observed at 1-year follow-up in comparison with 3-month follow-up (P < .0001), with a good outcome achieved in 62.5% of patients and an acceptable quality of life restored. CONCLUSIONS: One-year follow-up identifies delayed asymptomatic arterial abnormalities in patients treated with the Solitaire device.

Arterial spin labeling (ASL) perfusion: techniques and clinical use.

Arterial spin labeling (ASL) perfusion is a MRI technique to quantify tissue blood flow. ASL is a non-invasive technique that labels the protons in the arterial blood by radiofrequency pulses, without the exogenous injection of contrast media. This article has three goals: 1) present the principles of ASL perfusion, the types of labeling and the ways to obtain the mapping; 2) specify and the quality criteria for the mapping obtained, while emphasizing the artifacts; and 3) describe the main encephalic and renal applications.

Non-ECG-gated unenhanced MRA of the carotids: optimization and clinical feasibility.

OBJECTIVES: To optimise and assess the clinical feasibility of a carotid non-ECG-gated unenhanced MRA sequence. METHODS: Sixteen healthy volunteers and 11 patients presenting with internal carotid artery (ICA) disease underwent large field-of-view balanced steady-state free precession (bSSFP) unenhanced MRA at 3T. Sampling schemes acquiring the k-space centre either early (kCE) or late (kCL) in the acquisition window were evaluated. Signal and image quality was scored in comparison to ECG-gated kCE unenhanced MRA and TOF. For patients, computed tomography angiography was used as the reference. RESULTS: In volunteers, kCE sampling yielded higher image quality than kCL and TOF, with fewer flow artefacts and improved signal homogeneity. kCE unenhanced MRA image quality was higher without ECG-gating. Arterial signal and artery/vein contrast were higher with both bSSFP sampling schemes than with TOF. The kCE sequence allowed correct quantification of ten significant stenoses, and it facilitated the identification of an infrapetrous dysplasia, which was outside of the TOF imaging coverage. CONCLUSIONS: Non-ECG-gated bSSFP carotid imaging offers high-quality images and is a promising sequence for carotid disease diagnosis in a short acquisition time with high spatial resolution and a large field of view. KEY POINTS: • Non-ECG-gated unenhanced bSSFP MRA offers high-quality imaging of the carotid arteries. • Sequences using early acquisition of the k-space centre achieve higher image quality. • Non-ECG-gated unenhanced bSSFP MRA allows quantification of significant carotid stenosis. • Short MR acquisition times and ungated sequences are helpful in clinical practice. • High 3D spatial resolution and a large field of view improve diagnostic performance.

[Innovations in functional MR imaging of the brain: arterial spin labeling and diffusion]. / Innovations en IRM fonctionnelle cérébrale : marquage de spins artériels et diffusion.

The standard technique for brain activation functional MRI (fMRI) is the BOLD sequence. Two new techniques have emerged: arterial spin labeling (ASL) MRI and diffusion MRI. Both have the theoretical advantage of more accurately directly demonstrating neuronal activation compared to BOLD imaging, resulting in improved spatial and temporal resolution. ASL is a perfusion sequence using labeled arterial protons as an endogenous perfusion agent. In spite of methodological difficulties, quantitative CBF measurements are possible. ASL is less susceptible to venous contamination than BOLD and more reproducible. Diffusion MRI evaluates neuronal activation at the cellular level with the prospect of excellent spatial resolution. The main limitations for both techniques are the technical difficulties in the acquisition and the low SNR. AS such, ASL is not widely used clinically and diffusion remains in the field of research. However, the increasing availability of 3T MR systems coupled with multi-channel surface coils and improved postprocessing techniques should improve the detection of the brain activation signal. It is thus possible that these techniques could become clinically available either in complement to or as a replacement for BOLD imaging.

Quality-evaluation scheme for cerebral time-resolved 3D contrast-enhanced MR angiography techniques.

BACKGROUND AND PURPOSE: No practical tool has been reported in the literature to evaluate the quality of cerebral TR-3D-CE-MRA techniques. Our study assessed a large list of parameters used to propose a quality-evaluation scheme for TR-3D-CE-MRA. MATERIALS AND METHODS: A large list of visual and quantitative parameters used to study the quality of images was collected from the literature and evaluated in 19 healthy patients and 11 patients with arteriovenous shunts who had undergone both CENTRA keyhole TR-3D-CE-MRA at 3T and CCA. Several observers evaluated the visual parameters, such as the diagnostic confidence index, artifacts, maximum vascular signal intensity, arterial-to-venous separation, and visibility of 17 arteries and 7 veins; and quantitative parameters, such as maximum arterial SI, arteriovenous transit time, arteriovenous contrast curve, and ADW. A statistical analysis was used to determine interobserver reproducibility of the visual parameters, to calculate the sensitivity of TR-3D-CE-MRA for detecting each vessel (with CCA as standard of reference), and to compare the results of the visual and quantitative evaluations. RESULTS: Diagnostic confidence index, artifacts, arterial-to-venous separation, and 4 vessels-the PICA, ophthalmic and occipital arteries, and the ISS-demonstrated high reproducibility and sensitivity. The ADW was the most reliable dynamic quantitative parameter and was correlated with arterial-to-venous separation. CONCLUSIONS: The image quality of TR-3D-CE-MRA can be effectively evaluated with a scheme of 1 quantitative and 7 visual parameters.