Impact of an AI software on the diagnostic performance and reading time for the detection of cerebral aneurysms on time of flight MR-angiography.

PURPOSE: To evaluate the impact of an AI-based software trained to detect cerebral aneurysms on TOF-MRA on the diagnostic performance and reading times across readers with varying experience levels. METHODS: One hundred eighty-six MRI studies were reviewed by six readers to detect cerebral aneurysms. Initially, readings were assisted by the CNN-based software mdbrain. After 6 weeks, a second reading was conducted without software assistance. The results were compared to the consensus reading of two neuroradiological specialists and sensitivity (lesion and patient level), specificity (patient level), and false positives per case were calculated for the group of all readers, for the subgroup of physicians, and for each individual reader. Also, reading times for each reader were measured. RESULTS: The dataset contained 54 aneurysms. The readers had no experience (three medical students), 2 years experience (resident in neuroradiology), 6 years experience (radiologist), and 12 years (neuroradiologist). Significant improvements of overall specificity and the overall number of false positives per case were observed in the reading with AI support. For the physicians, we found significant improvements of sensitivity on lesion and patient level and false positives per case. Four readers experienced reduced reading times with the software, while two encountered increased times. CONCLUSION: In the reading with the AI-based software, we observed significant improvements in terms of specificity and false positives per case for the group of all readers and significant improvements of sensitivity and false positives per case for the physicians. Further studies are needed to investigate the effects of the AI-based software in a prospective setting.

Stenting with dual-layer CGuard stent in acute sub-occlusive carotid artery stenosis and in tandem occlusions: a monocentric study.

PURPOSE: Double-layer design carotid stents have been cast in a negative light since several investigations reported high rates of in-stent occlusions, at least in the acute setting of tandem occlusions. CGuard is a new generation double-layered stent that was designed to prevent periinterventional embolic events. The aim of this study was to analyze the safety and efficacy of the CGuard in emergent CAS and for the acute treatment of tandem occlusions in comparison with the single-layer Carotid Wallstent (CWS) system. METHODS: All patients who underwent CAS with CGuard or CWS after intracranial mechanical thrombectomy (MT) between 11/2018 and 12/2022 were identified from our local thrombectomy registry. Clinical, interventional and neuroimaging data were analyzed. Patency of the stent was assessed within 72 h. Intracranial hemorrhage and modified Rankin score (mRS) at discharge were the main endpoints. RESULTS: In total, 86 stent procedures in 86 patients were included (CWS: 44, CGuard: 42). CGuard had a lower, but not statistically significant rate (p = 0.431) of in-stent occlusions (n = 2, 4.8%) when compared to the CWS (n = 4, 9.1%). Significant in-stent stenosis was found in one case in each group. There was no statistically significant difference in functional outcome at discharge between the two groups with a median mRS for CGuard of 2 (IQR:1-5) vs. CWS 3 (IQR:2-4). CONCLUSION: In our series, the rate of in-stent occlusions after emergent CAS was lower with the dual-layer CGuard when compared to the monolayer CWS. Further data are needed to evaluate the potential benefit of the design in more detail.

Modification of In-Hospital Recommendation and Prescription of Anticoagulants for Secondary Prevention of Stroke after Launch of Direct Oral Anticoagulants and Change of National Guidelines.

INTRODUCTION: Approximately 1 out of 4 stroke patients suffers ischemic stroke secondary to atrial fibrillation (AF). Although indicated, withholding of anticoagulants for secondary prevention is a widespread phenomenon. OBJECTIVE: We examined the longitudinal change of recommendation and prescription of secondary preventive anticoagulation in AF patients in an acute stroke center setting focusing on the impact of the introduction of direct oral anticoagulants (DOACs) and the change of national stroke prevention guidelines. METHODS: Consecutive patients admitted with an acute cerebrovascular ischemic event underwent regular diagnostic work-up. Pseudonymized clinical data were entered into the institution's stroke registry. In those patients with AF, discharge letters were collected and evaluated for temporal trends and affecting factors of recommended and prescribed antithrombotic secondary medication at the time of discharge from hospital. RESULTS: Of 7,175 patients admitted between January 2009 and December 2018, 1,812 (25.3%) suffered stroke caused by AF. Frequency of patients with recommended anticoagulation increased within the observation period from 66.7 to 95.8% (per year; adjusted odds ratio [OR], 1.309; confidence interval [CI], 1.153-1.486). Independently from this time trend, DOAC approval (adjusted OR, 4.026; CI 1.962-8.265) and guideline change (adjusted OR, 2.184; CI, 1.006-4.743) were associated with an increasing frequency of recommendation for anticoagulation. The rate of patients already receiving recommended anticoagulation for secondary prevention at discharge increased from 42.1 to 62.5%. Introduction of DOACs was not associated with this trend, and guideline change was even associated with decreasing frequency of anticoagulated patients at hospital discharge (adjusted OR, 0.641; CI, 0.414-0.991). Fear of early intracerebral bleeding was the most common reason for withholding anticoagulation (37%) at hospital discharge and stayed stable during the observation period. CONCLUSIONS: Changing national guidelines with discard of contraindications for anticoagulation and the introduction of DOACs led to a broader recommendation of oral anticoagulation. However, both, new guidelines and DOACs, were not found to be associated with an increasing percentage of patients discharged from our hospital already on recommended anticoagulant prevention. This might be explained by the decreasing length of hospital stay during the study period and a missing evidence of early bleeding risk of DOACs in patients with acute brain infarction. Evidence-based data to close this therapeutic gap are needed.

The Dual-layer CGuard Stent Is Safe and Effective in Emergent Carotid Artery Stenting and in Tandem Occlusions: a Multi-centric Study.

BACKGROUND: Dual-layer stents have fallen into disrepute after several studies reported high rates of in-stent occlusions in acute stroke treatments. The CGuard stent is a new-generation hybrid dual-layer stent that has been designed to provide less thrombogenicity and to prevent peri- and postinterventional emboli. The aim of the study is to evaluate the safety and efficacy of the CGuard stent for the acute treatment of occlusion or high-grade stenosis of the extracranial internal carotid artery (ICA) in patients with acute ischemic stroke (AIS) with and without concomitant intracranial large vessel occlusion (LVO). METHODS: All patients who underwent emergent carotid artery stenting (CAS) with the CGuard stent were identified and analyzed from the stroke registries from four tertiary German stroke centers. Clinical, procedural, and imaging data were evaluated. Stent patency within 72 h, intracranial hemorrhage, and modified Rankin score (mRS) at discharge were the safety and efficacy end points. RESULTS: Overall, ninety-six patients were included (mean age 70.2 ± 11.8, 66 males (68.8%), median NIHSS score at admission 11 (7-17), IV lysis: n = 44 (45.8%)). Stent placement was successful in all patients. Eighty-three (86.4%) patients had tandem occlusions. In-stent occlusion occurred in 5 patients (5.2%) and 3 patients developed early in-stent stenosis (3.1%). Median mRS at discharge was 2 (1-4). CONCLUSION: In this multicenter study, the use of the dual-layer CGuard stent for emergent CAS, particularly in tandem occlusions, was safe and resulted in low rates of in-stent occlusions.

Aneurysm Treatment With the Pipeline Vantage Embolization Device in Retrospective Evaluation: Periprocedural Results from the Pipe-VADER Study.

OBJECTIVE: The Pipeline Vantage Embolization Device is a fourth-generation flow diverter with an antithrombotic coating and a reduced profile compared to previous Pipeline versions. The objective of this study was to evaluate the procedural feasibility, safety, and efficacy of this device. METHODS: The Pipe-VADER study was designed as a retrospective, observational study of consecutive patients treated with the Vantage at 3 neurovascular centers. Patient and aneurysm characteristics, procedural parameters, early complications, and extent of postinterventional contrast retention were analyzed on an intention-to-treat basis. RESULTS: Twenty-eight patients with 31 aneurysms (median size: 5.0 mm, posterior circulation: 4 [12.9%], ruptured: 5 [16.1%]) were included. The technical success rate was 100%, with multiple stents used in 4/30 (13.3%) procedures. Of the 30 procedures, adjunctive coiling was performed in 3 (10.0%) and balloon angioplasty in 2 (6.7%). Median procedure time was 62 minutes. Procedural ischemic stroke occured in 4 (13.3%) cases, whereof 2 were major strokes (6.6%). There were no hemorrhagic complications. Initial contrast retention was observed in 29/31 (93.5%) aneurysms. All 27 overstented side vessels were patent at the end of the procedure. Short-term follow-up (median: 5 months) showed complete and favorable occlusion rates of 70% (14/20) and 80% (16/20), respectively. CONCLUSIONS: The new Pipeline Vantage appears to be safe and feasible for the treatment of intracranial aneurysms and warrants further evaluation.

Artificial T1-Weighted Postcontrast Brain MRI: A Deep Learning Method for Contrast Signal Extraction.

OBJECTIVES: Reducing gadolinium-based contrast agents to lower costs, the environmental impact of gadolinium-containing wastewater, and patient exposure is still an unresolved issue. Published methods have never been compared. The purpose of this study was to compare the performance of 2 reimplemented state-of-the-art deep learning methods (settings A and B) and a proposed method for contrast signal extraction (setting C) to synthesize artificial T1-weighted full-dose images from corresponding noncontrast and low-dose images. MATERIALS AND METHODS: In this prospective study, 213 participants received magnetic resonance imaging of the brain between August and October 2021 including low-dose (0.02 mmol/kg) and full-dose images (0.1 mmol/kg). Fifty participants were randomly set aside as test set before training (mean age ± SD, 52.6 ± 15.3 years; 30 men). Artificial and true full-dose images were compared using a reader-based study. Two readers noted all false-positive lesions and scored the overall interchangeability in regard to the clinical conclusion. Using a 5-point Likert scale (0 being the worst), they scored the contrast enhancement of each lesion and its conformity to the respective reference in the true image. RESULTS: The average counts of false-positives per participant were 0.33 ± 0.93, 0.07 ± 0.33, and 0.05 ± 0.22 for settings A-C, respectively. Setting C showed a significantly higher proportion of scans scored as fully or mostly interchangeable (70/100) than settings A (40/100, P < 0.001) and B (57/100, P < 0.001), and generated the smallest mean enhancement reduction of scored lesions (-0.50 ± 0.55) compared with the true images (setting A: -1.10 ± 0.98; setting B: -0.91 ± 0.67, both P < 0.001). The average scores of conformity of the lesion were 1.75 ± 1.07, 2.19 ± 1.04, and 2.48 ± 0.91 for settings A-C, respectively, with significant differences among all settings (all P < 0.001). CONCLUSIONS: The proposed method for contrast signal extraction showed significant improvements in synthesizing postcontrast images. A relevant proportion of images showing inadequate interchangeability with the reference remains at this dosage.

Multicenter Experience with the Pipeline Flex and Vantage with Shield Technology for Intracranial Aneurysm Treatment.

BACKGROUND AND PURPOSE: The Pipeline Embolization Device is a safe and effective treatment option for intracranial aneurysms. The newer Pipeline generations have received structural refinements and a surface modification to improve deliverability, procedural safety, and angiographic outcomes. This multicenter study evaluated the clinical safety and efficacy of the 2 surface-modified Pipeline iterations, Pipeline Vantage and Pipeline Flex with Shield Technology (PFS). MATERIALS AND METHODS: Consecutive patients treated between 2017 and 2023 were retrospectively reviewed for aneurysm characteristics, procedural details, complications, and angiographic outcomes. The safety end point was the rate of procedural and postprocedural major neurologic events occurring during the hospital stay. The efficacy end point was the rate of complete occlusion at last follow-up. RESULTS: One hundred forty-one patients underwent 112 Pipeline Vantage procedures and 32 PFS procedures for 147 aneurysms with a mean size of 8.0 (SD, 5.9) mm (11% ruptured, 16% posterior circulation, 18% nonsaccular morphology). All procedures were technically successful with a mean of 1.2 devices implanted. Balloon angioplasty was required in 20/144 (13.9%) procedures. Major neurologic adverse events occurred in 6/144 (4.2%) procedures (all ischemic stroke), resulting in death in 2 (1.4%) patients. There were no hemorrhagic complications. At a mean of 11 months, complete occlusion was achieved in 85/112 (75.9%) aneurysms, 15/112 (13.4%) had an entry remnant, and 12/112 (10.7%) had an aneurysm remnant. CONCLUSIONS: The results demonstrate high feasibility, procedural safety, and efficacy of the surface-modified Pipeline flow diverters.

Safety and efficacy of coated flow diverters in the treatment of cerebral aneurysms during single antiplatelet therapy: A multicenter study.

OBJECTIVE: This multicenter study evaluates the safety and efficacy of coated flow diverters (cFDs) for the treatment of cerebral aneurysms under single antiplatelet therapy (SAPT). METHODS: This is a retrospective, observational study of 41 patients (median age: 58 years) with 41 aneurysms (median size: 7 mm, 29 [71%] saccular, 9 [22%] ruptured) treated with cFDs at four neurovascular centers between 2020 and 2023. Scheduled cases received continuous SAPT starting seven days before the procedure. Emergency cases were treated with tirofiban followed by SAPT loading. The safety endpoint was ischemic complications occurring during the procedure and within four months of clinical follow-up. RESULTS: The Pipeline Vantage or Flex Shield was used in 26 (63%) procedures, the FRED X in 12 (29%), the p48/64 Hydrophilic Polymer Coating in 2 (5%), and the Derivo Embolization Device 2heal in 1 (2%). Single antiplatelet therapy consisted of prasugrel in 27 (66%) patients, ticagrelor in 9 (22%), and ASA in 5 (12%). There were 2 (5%) early ischemic complications (one minor stroke and one transient ischemic attack). There were no late ischemic complications in the four-month follow-up of 35 patients. The six dropouts included four nontreatment-related deaths after subarachnoid hemorrhage and two patients with a poor outcome after subarachnoid hemorrhage. Complete and favorable occlusion rates (median: 7 months) were 75% (27/36) and 89% (32/36), respectively. CONCLUSIONS: Coated flow diverter implantation in the setting of SAPT was safe and effective and warrants confirmation in a prospective comparative trial.

Safety and efficacy of coated flow diverters in the treatment of ruptured intracranial aneurysms: a retrospective multicenter study.

BACKGROUND: This multicenter study evaluated the safety and efficacy of coated flow diverters (cFDs) for the treatment of ruptured intracranial aneurysms. METHODS: Consecutive patients treated with different cFDs for ruptured aneurysms under tirofiban at eight neurovascular centers between 2016 and 2023 were retrospectively analyzed. The majority of patients were loaded with dual antiplatelet therapy after the treatment. Aneurysm occlusion was determined using the O'Kelly-Marotta (OKM) grading scale. Primary outcome measures were major procedural complications and aneurysmal rebleeding during hospitalization. RESULTS: The study included 60 aneurysms (posterior circulation: 28 (47%)) with a mean size of 5.8±4.7 mm. Aneurysm morphology was saccular in 28 (47%), blister-like in 12 (20%), dissecting in 13 (22%), and fusiform in 7 (12%). Technical success was 100% with a mean of 1.1 cFDs implanted per aneurysm. Adjunctive coiling was performed in 11 (18%) aneurysms. Immediate contrast retention was observed in 45 (75%) aneurysms. There was 1 (2%) major procedural complication (a major stroke, eventually leading to death) and no aneurysmal rebleeding. A good outcome (modified Rankin Scale 0-2) was achieved in 40 (67%) patients. At a mean follow-up of 6 months, 27/34 (79%) aneurysms were completely occluded (OKM D), 3/34 (9%) had an entry remnant (OKM C), and 4/34 (12%) had residual filling (OKM A or B). There was 1 (3%) severe in-stent stenosis during follow-up that was treated with balloon angioplasty. CONCLUSIONS: Treatment of ruptured aneurysms with cFDs was reasonably safe and efficient and thus represents a valid treatment option, especially for complex cases.

School of Thrombectomy-A 3-Step Approach to Perform Acute Stroke Treatment with Simulator Training and Virtual Supervision by Remote Streaming Support (RESS).

As the number of neurointerventional procedures continues to increase, so does the need for well-trained neurointerventionalists. The purpose of this work was to establish and assess a systematic 3­step approach to perform acute stroke treatment including simulator training and virtual supervision by remote streaming support (RESS). Five trainees (four men, one women) who have completed the 3­step approach have answered an 11-item questionnaire (5-point Likert scale) in order to evaluate training step 1 (simulator). Furthermore, all trainees and one supervisor (female) answered a standardized questionnaire following the initial 15 consecutive thrombectomies for each trainee, corresponding to a total of 75 thrombectomies. The simulator training yielded learning benefits and confidence gain to perform MT on patients. The RESS approach facilitated the translation during the first independently performed thrombectomies on patients. In summary, the presented 3­step approach increases the level of safety, as reported by the trainees and supervisor in this study and may enable an accelerated training of neurointerventionalists.