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Recent evidence suggests a beneficial effect of endovascular thrombectomy in acute ischaemic stroke with large infarct; however, previous trials have relied on multimodal brain imaging, whereas non-contrast CT is mostly used in clinical practice. In a prospective multicentre, open-label, randomised trial, patients with acute ischaemic stroke due to large vessel occlusion in the anterior circulation and a large established infarct indicated by an Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) of 3–5 were randomly assigned using a central, web-based system (using a 1:1 ratio) to receive either endovascular thrombectomy with medical treatment or medical treatment (ie, standard of care) alone up to 12 h from stroke onset. The study was conducted in 40 hospitals in Europe and one site in Canada. The primary outcome was functional outcome across the entire range of the modified Rankin Scale at 90 days, assessed by investigators masked to treatment assignment. The primary analysis was done in the intention-to-treat population. Safety endpoints included mortality and rates of symptomatic intracranial haemorrhage and were analysed in the safety population, which included all patients based on the treatment they received. This trial is registered with ClinicalTrials.gov , NCT03094715. From July 17, 2018, to Feb 21, 2023, 253 patients were randomly assigned, with 125 patients assigned to endovascular thrombectomy and 128 to medical treatment alone. The trial was stopped early for efficacy after the first pre-planned interim analysis. At 90 days, endovascular thrombectomy was associated with a shift in the distribution of scores on the modified Rankin Scale towards better outcome (adjusted common OR 2·58 [95% CI 1·60–4·15]; p=0·0001) and with lower mortality (hazard ratio 0·67 [95% CI 0·46–0·98]; p=0·038). Symptomatic intracranial haemorrhage occurred in seven (6%) patients with thrombectomy and in six (5%) with medical treatment alone. Endovascular thrombectomy was associated with improved functional outcome and lower mortality in patients with acute ischaemic stroke from large vessel occlusion with established large infarct in a setting using non-contrast CT as the predominant imaging modality for patient selection. EU Horizon 2020. [ABSTRACT FROM AUTHOR]

Interventional neuroradiology (INR) has not yet received official certification as a surgical subspecialty in Ukraine. Consequently, there is uncertainty surrounding the availability of a neurosurgical internship and a structured INR training program to provide neuroendovascular procedures. In recent years, mechanical thrombectomy has become the standard of care for acute ischemic stroke caused by large vessel occlusion, as supported by evidence-based guidelines. This emphasizes the need for INR specialists, which far exceeds the current supply. Although stroke centres with interventional neuroradiological facilities have been established to address this shortage in Ukraine, they lack highly skilled staff. Following the relaxation of COVID-19 migration restrictions, the Ukrainian medical system faced new limitations due to ongoing wartime conditions. In such circumstances, international cooperation becomes crucial to ensuring the safe and effective implementation of new technologies into routine medical practice. We successfully integrated teleproctoring into our hands-on course and found it to be an effective and promising approach, especially considering the uncertainty of the future and the presence of wartime migration restrictions in Ukraine. Teleproctoring hands-on course has the potential to provide young specialists with experienced mentors and valuable initial experience and can serve as a valuable adjunct for the improvement of surgeons confidence. [ABSTRACT FROM AUTHOR]

The article focuses on the evidence provided by the five published randomized controlled trials (RCT) in which endovascular thrombectomy (EVT) combined with medical treatment like intravenous (IV) tissue plasminogen activator (tPA) (IV thrombolysis, IVT) improves the outcomes of patients with acute ischemic stroke. Topics discussed include the benefit of EVT, recommendations on the organisation of interventional care in acute stroke, and questions to identify the potential of the evidence.

A new era of stroke treatment may have begun with mechanical thrombectomy (MT) by fully deployed closed-cell self-expanding stents (stent-triever). Multiple case series and the first randomised controlled trials (RCTs) have now been published. More studies are under way involving large numbers of patients, which in turn has resulted in less strict 'pragmatic' study protocols. Problems with current trials include a lack of standardisation in the conduct of the recanalisation procedure, the definition of primary endpoints such as the grade of arterial recanalisation and tissue reperfusion, and the post-surgical care provided. In Part 1 of this two part series, we outline the current situation and the major research questions. [ABSTRACT FROM AUTHOR]

Based on current data and experience, the joint working group of the European Society of Minimally Invasive Neurological Therapy (ESMINT) and the European Society of Neuroradiology (ESNR) make suggestions on trial design and conduct aimed to investigate therapeutic effects of mechanical thrombectomy (MT). We anticipate that this roadmap will facilitate the setting up and conduct of successful trials in close collaboration with our neighbouring disciplines. [ABSTRACT FROM AUTHOR]

Introduction: A fast and reproducible quantification of the recurrence volume of coiled aneurysms is required to enable a more timely evaluation of new coils. This paper presents two registration schemes for the semi-automatic quantification of aneurysm recurrence volumes based on baseline and follow-up 3D MRA TOF datasets. Methods: The quantification of shape changes requires a previous definition of corresponding structures in both datasets. For this, two different rigid registration methods have been developed and evaluated. Besides a state-of-the-art rigid registration method, a second approach integrating vessel segmentations is presented. After registration, the aneurysm recurrence volume can be calculated based on the difference image. The computed volumes were compared to manually extracted volumes. Results: An evaluation based on 20 TOF MRA datasets (baseline and follow-up) of ten patients showed that both registration schemes are generally capable of providing sufficient registration results. Regarding the quantification of aneurysm recurrence volumes, the results suggest that the second segmentation-based registration method yields better results, while a reduction of the computation and interaction time is achieved at the same time. Conclusion: The proposed registration scheme incorporating vessel segmentation enables an improved quantification of recurrence volumes of coiled aneurysms with reduced computation and interaction time. [ABSTRACT FROM AUTHOR]

Three randomised controlled trials (RCTs) comparing outcomes after carotid artery stenting (CAS) with carotid endarterectomy (CEA) have recently been published. Recent systematic reviews have recommended that CAS is no longer justified for patients suitable for CEA. Indeed, in many centres, pooled data of RCTs show higher peri-operative risk of performing CAS vs. CEA with comparable long-term efficacy. Due to limitations in SPACE, EVA3S and ICSS study design and conduct, the inferiority of CAS to CEA as a method remains inconclusive. The goal of this review is not to discredit these trials but to develop a more differentiated and critical interpretation of the data and to create more discussion. It will discuss the necessity of RCTs for Interventional Neuroradiology in general and particular problems in study design (non-inferiority design and interpretation of results, clinical equipoise, study endpoints), practical study conduct difficulties (operator and centre experience, antiaggregation, timing of treatment) and the interpretation of the results (relation of internal and external validity, procedural complexity, the 68-year surprise, longer-term outcome). A premature rejection of CAS based on the data from these studies could harm future patients who would have had benefited from this procedure. For the time being, there is no reason why centres with good and independently controlled track records should stop performing CAS. Designing a single cooperative European trial that incorporates the lessons learned would be major step forward. [ABSTRACT FROM AUTHOR]

INTRODUCTION The objective of our study was to determine whether the combination of hypointense spots (“cerebral microbleeds,” CMBs) with a leukoaraiosis is associated with the risk of parenchymal hematoma (PH) after thrombolytic therapy. PATIENTS AND METHODS We analyzed magnetic resonance imaging (MRI) scans acquired within 6 hours after symptom onset from 100 ischemic stroke patients. Multiparametric MRI including a T2*-weighted (T2*w) MRI and fluid attenuated inversion recovery (FLAIR) was performed before thrombolysis in all patients. Initial T2*w imaging was rated by two independent observers for the presence of CMBs smaller than 5 mm. White matter changes were evaluated using an adapted scale of Fazekas and Schmidt. PH was defined in follow-up imaging. FINDINGS A PH was observed in seven per 100 patients. CMBs were detected by observer 1 in 22 and observer 2 in 20 patients. We found a very low sensitivity (0.14) for prediction of PH by the presence of CMBs. We found a concordant increase in the rate of PH when the periventricular hyperintensity in FLAIR was larger than a thin lining. Sensitivity was good-to-perfect (0.86 and 1.00, observers 1 and 2) and specificity was substantial (0.65 and 0.66). Using the combination of a periventricular matter lesion (PVML)>1 and the presence of CMBs did not improve the prediction of PH. DISCUSSION A marked periventricular hyperintensity in FLAIR imaging seems to be associated with a substantially increased risk of PH. A combination of CMBs with leukoaraiosis scores did not appear to be beneficial for prognosis. [ABSTRACT FROM AUTHOR]

Despite the high grade of standardisation of study protocols, there is still room for variability among the centres in specific treatment aspects. We evaluated the treatment risk in stent-protected angioplasty of the carotid versus endarterectomy (SPACE) associated with the specific patient enrolment rates of the centres. The analysed endpoints were ipsilateral stroke or death [primary outcome event (pOE)] and any stroke or death [secondary outcome event (sOE)] until 30 days after treatment. A binary logistic regression analysis with random effects was performed separately for each treatment arm. The centres were secondarily categorised in three classes: I) ≥25 patients enrolled, II) ten to 24 patients and III) <10 patients and a hierarchic log linear model was fitted to test the three-way interaction of treatment, number of patients per class and outcome. The random effects logistic regression analysis in the carotid artery stenting (CAS) arm proved a significant increase in pOE with decreasing number of patients enrolled (−0.0190 ± 0.0085, p = 0.025, deviance 35.7 with 32 df), whereas no such effect was found in the carotid endartectomy (CEA) arm (−0.010 ± 0.008, p = 0.24, deviance 39.78 with 32 df). In the log linear model, there was a significant interaction between treatment, number of patients per centre and sOE ( p = 0.023). The odds ratios for sOE in the enrolment classes (CAS vs. CEA) were 0.98 (95% CI 0.50–1.94, p = 0.95) for class I, 1.13 (95% CI 0.47–2.77, p = 0.77) for class II and 11.56 (95% CI 1.40–253.45, p = 0.01) for class III centres. Despite rigorous standardisation and quality requirements for operator qualification, there seemed to be a decrease in complication rate with increasing patient enrolment numbers in the CAS arm while this signal could not be detected in the CEA arm of SPACE. [ABSTRACT FROM AUTHOR]

Black dots in the brain parenchyma diagnosed in T2*-weighted magnetic resonance imaging should be interpreted in light of the patient's history as well as the location, number and distribution of the lesions and associated imaging findings. These dots will correspond to haemoglobin degradation products in most of the cases referred to as cerebral microbleeds in patients with small vessel disease. Cerebral microbleeds have a prevalence of 5.7 % (range 3.7–7.7%) and are observed more frequently with increasing age. cerebral microbleeds have been observed in 47–80% of the primary intracerebral haemorrhage patients and in 0–78% of the patients with ischaemic cerebrovascular disease and appear to be a general marker of various types of bleeding-prone, small vessel disease and a predictor of recurrent vascular events. The occurrence and the number of cerebral microbleeds are associated with the degree of cerebral white matter abnormalities. Current data does not support the hypothesis that cerebral microbleeds are associated with a higher risk for a clinically relevant intracerebral haemorrhage, after anticoagulation/antiaggregation therapy, or after thrombolytic therapy in stroke patients. Therefore, the current data do not support the general exclusion of patients from therapy based on the presence of cerebral microbleeds. In the future, cerebral microbleeds may be incorporated into the design of clinical trials of anticoagulation/antiaggregation drugs in stroke patients for potential individual stratification for both the risk of recurrent ischaemic stroke and for the risk of intracerebral haemorrhage. [ABSTRACT FROM AUTHOR]

Background: We applied magnetic resonance imaging to analyze the degree of local diffusion and perfusion abnormalities and the status of reperfusion in regions with subsequent hemorrhagic transformation (HT). Methods: 51 patients with acute ischemic stroke were studied by diffusion- and perfusion-weighted imaging within 3.0 ± 0.8 h, on day 1 and days 5–8. After realignment of the image data sets, the parameter maps of the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and cerebral blood volume (CBV), and mean transit time were analyzed in the area of subsequent HT. The degree of local diffusion and perfusion impairment in the HT area was compared with the entire diffusion and perfusion abnormality. Reperfusion status was separately assessed for the entire perfusion abnormality and the HT area. Results: HT was observed in 19/51 patients (37.2%) within 8 days after symptom onset. Areas destined for HT revealed a more severe decrease in ADC (to 70 ± 13%; p < 0.01), CBV (to 31 ± 26%; p < 0.001) and CBF (to 28 ± 19%; p < 0.001) compared to the entire perfusion abnormality. Local reperfusion in the HT area was seen in 18/19 patients. The presence of HT did not coincide with a worse clinical outcome. Discussion: HT is the result of reperfusion in the region with the most severe local perfusion impairment and does not influence the neurological outcome. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The integrity of vessel walls and changes in blood flow are involved in many diseases, and information about these anatomical and physiological conditions is important for a diagnosis. There are several different angiography methods that can be used to generate images for diagnostic purposes, but often using different imaging techniques and MR sequences. The purpose of this study was to develop a method that allows time-resolved, vessel-selective simultaneous bright and black blood imaging by vesselselective blood saturation. Measurements in six volunteers were performed to evaluate the time-resolved bright blood angiography and the significance of the generated black blood contrast. It was shown that this method can be used to generate a black blood contrast with a sufficient signal difference to the surrounding gray matter in addition to the time-resolved and vessel-selective bright blood contrast. Using post-processing methods, whole brain angiograms can be calculated from the acquired data. [ABSTRACT FROM AUTHOR]

In the article the editor reflects on the limitations of research studies concerning the treatment of carotid stenosis. The editor discusses three strategies for improving randomised controlled trials (RCTs), and opines that carotid stenosis therapy is the best disease suitable for investigation in the neuroradiology discipline.

The authors reflect on the significance of utilizing a randomized trial of unrupted brain arteriovenous malformations (ARUBA) study for the treatment of unrupted arteriovenous malformations (AVMs). They discusses the several benefits offered by ARUBA in evaluating therapeutic decisions against AVMs. The authors assert that the study helps to identify AVMs-associated risks which may affect patients.

Background: There is growing evidence suggesting efficacy of endovascular therapy for M2 occlusions of the middle cerebral artery. More than one recanalization attempt is often required to achieve successful reperfusion in M2 occlusions, associated with general concerns about the safety of multiple maneuvers in these medium vessel occlusions. Aim: The aim of this study was to investigate the association between the number of recanalization attempts and functional outcomes in M2 occlusions in comparison with large vessel occlusions (LVO). Methods: Retrospective multicenter cohort study of patients who underwent endovascular therapy for primary M2 occlusions. Patients were enrolled in the German Stroke Registry at 1 of 25 comprehensive stroke centers between 2015 and 2021. The study cohort was subdivided into patients with unsuccessful reperfusion (mTICI 0–2a) and successful reperfusion (mTICI 2b–3) at first, second, third, fourth, or ⩾fifth recanalization attempt. Primary outcome was 90-day functional independence defined as modified Rankin Scale score of 0–2. Safety outcome was the occurrence of symptomatic intracranial hemorrhage. Internal carotid artery or M1 occlusions were defined as LVO and served as comparison group. Results: A total of 1078 patients with M2 occlusion were included. Successful reperfusion was observed in 87.1% and 90-day functional independence in 51.9%. The rate of functional independence decreased gradually with increasing number of recanalization attempts (p < 0.001). In both M2 occlusions and LVO, successful reperfusion within three attempts was associated with greater odds of functional independence, while success at ⩾fourth attempt was not. Patients with ⩾4 attempts exhibited higher rates of symptomatic intracranial hemorrhage in M2 occlusions (6.5% vs 2.7%, p = 0.02) and LVO (7.2% vs 3.5%, p < 0.001). Conclusion: This study suggests a clinical benefit of successful reperfusion within three recanalization attempts in endovascular therapy for M2 occlusions, which was similar in LVO. Our findings reduce concerns about the risk–benefit ratio of multiple attempts in M2 medium vessel occlusions. Data access statement: The data that support the findings of this study are available on reasonable request after approval of the German Stroke Registry (GSR) steering committee. Clinical Trial Registration Information: ClinicalTrials.gov Identifier: NCT03356392 [ABSTRACT FROM AUTHOR]

The link between metabolic syndrome (MetS) and neurodegenerative as well as cerebrovascular conditions holds substantial implications for brain health in at-risk populations. This study elucidates the complex relationship between MetS and brain health by conducting a comprehensive examination of cardiometabolic risk factors, brain morphology, and cognitive function in 40,087 individuals. Multivariate, data-driven statistics identified a latent dimension linking more severe MetS to widespread brain morphological abnormalities, accounting for up to 71% of shared variance in the data. This dimension was replicable across sub-samples. In a mediation analysis, we could demonstrate that MetS-related brain morphological abnormalities mediated the link between MetS severity and cognitive performance in multiple domains. Employing imaging transcriptomics and connectomics, our results also suggest that MetS-related morphological abnormalities are linked to the regional cellular composition and macroscopic brain network organization. By leveraging extensive, multi-domain data combined with a dimensional stratification approach, our analysis provides profound insights into the association of MetS and brain health. These findings can inform effective therapeutic and risk mitigation strategies aimed at maintaining brain integrity. [ABSTRACT FROM AUTHOR]

Background and purpose: In ischemic stroke, the impact of short‐ versus long‐term blood glucose level (BGL) on early lesion pathophysiology and functional outcome has not been assessed. The purpose of this study was to directly compare the effect of long‐term blood glucose (glycated hemoglobin [HbA1c]) versus serum BGL on early edema formation and functional outcome. Methods: Anterior circulation ischemic stroke patients who underwent mechanical thrombectomy after multimodal computed tomography (CT) on admission were analyzed. Endpoints were early ischemic cerebral edema, measured by quantitative net water uptake (NWU) on initial CT and functional independence at Day 90. Results: A total of 345 patients were included. Patients with functional independence had significantly lower baseline NWU (3.1% vs. 8.3%; p < 0.001) and lower BGL (113 vs. 123 mg/dL; p < 0.001) than those without functional independence, while HbA1c levels did not differ significantly (5.7% vs. 5.8%; p = 0.15). A significant association was found for NWU and BGL (ß = 0.02, 95% confidence interval [CI] 0.006–0.03; p = 0.002), but not for HbA1c and NWU (ß = −0.16, 95% CI −0.53–0.21; p = 0.39). Mediation analysis showed that 67% of the effect of BGL on functional outcome was mediated by early edema formation. Conclusion: Aggravated early edema and worse functional outcome was associated with elevated short‐term serum BGL, but not with HbA1c levels. Hence, the link between short‐term BGL and early edema development might be used as a target for adjuvant therapy in patients with ischemic stroke. [ABSTRACT FROM AUTHOR]

Objectives: The Alberta Stroke Program Early CT Score (ASPECTS) is a semi-quantitative method to evaluate the severity of early ischemic change on non-contrast computed tomography (NCCT) in patients with acute ischemic stroke (AIS). In this work, we propose an automated ASPECTS method based on large cohort of data and machine learning. Methods: For this study, we collected 3626 NCCT cases from multiple centers and annotated directly on this dataset by neurologists. Based on image analysis and machine learning methods, we constructed a two-stage machine learning model. The validity and reliability of this automated ASPECTS method were tested on an independent external validation set of 300 cases. Statistical analyses on the total ASPECTS, dichotomized ASPECTS, and region-level ASPECTS were presented. Results: On an independent external validation set of 300 cases, for the total ASPECTS results, the intraclass correlation coefficient between automated ASPECTS and expert-rated was 0.842. The agreement between ASPECTS threshold of ≥ 6 versus < 6 using a dichotomized method was moderate (κ = 0.438, 0.391–0.477), and the detection rate (sensitivity) was 86.5% for patients with ASPECTS threshold of ≥ 6. Compared with the results of previous studies, our method achieved a slight lead in sensitivity (67.8%) and AUC (0.845), with comparable accuracy (78.9%) and specificity (81.2%). Conclusion: The proposed automated ASPECTS method driven by a large cohort of NCCT images performed equally well compared with expert-rated ASPECTS. This work further demonstrates the validity and reliability of automated ASPECTS evaluation method. Clinical relevance statement: The automated ASPECTS method proposed by this study may help AIS patients to receive rapid intervention, but should not be used as a stand-alone diagnostic basis. Key Points: NCCT-based manual ASPECTS scores were poorly consistent. Machine learning can automate the ASPECTS scoring process. Machine learning model design based on large cohort data can effectively improve the consistency of ASPECTS scores. [ABSTRACT FROM AUTHOR]

Net water uptake (NWU) is a quantitative imaging biomarker used to assess cerebral edema resulting from ischemia via Computed Tomography (CT)-densitometry. It serves as a strong predictor of clinical outcome. Nevertheless, NWU measurements on follow-up CT scans after mechanical thrombectomy (MT) can be affected by contrast staining. To improve the accuracy of edema estimation, virtual non-contrast images (VNC-I) from dual-energy CT scans (DECT) were compared to conventional polychromatic CT images (CP-I) in this study. We examined NWU measurements derived from VNC-I and CP-I to assess their agreement and predictive value in clinical outcome. 88 consecutive patients who received DECT as follow-up after MT were included. NWU was quantified on CP-I (cNWU) and VNC-I (vNWU). The clinical endpoint was functional independence at discharge. cNWU and vNWU were highly correlated (r = 0.71, p < 0.0001). The median difference between cNWU and vNWU was 8.7% (IQR: 4.5–14.1%), associated with successful vessel recanalization (mTICI2b-3) (ß: 11.6%, 95% CI 2.9–23.0%, p = 0.04), and age (ß: 4.2%, 95% CI 1.3–7.0%, p = 0.005). The diagnostic accuracy to classify outcome between cNWU and vNWU was similar (AUC:0.78 versus 0.77). Although there was an 8.7% median difference, indicating potential edema underestimation on CP-I, it did not have short-term clinical implications. [ABSTRACT FROM AUTHOR]

Net water uptake (NWU) is a quantitative imaging biomarker used to assess cerebral edema resulting from ischemia via Computed Tomography (CT)-densitometry. It serves as a strong predictor of clinical outcome. Nevertheless, NWU measurements on follow-up CT scans after mechanical thrombectomy (MT) can be affected by contrast staining. To improve the accuracy of edema estimation, virtual non-contrast images (VNC-I) from dual-energy CT scans (DECT) were compared to conventional polychromatic CT images (CP-I) in this study. We examined NWU measurements derived from VNC-I and CP-I to assess their agreement and predictive value in clinical outcome. 88 consecutive patients who received DECT as follow-up after MT were included. NWU was quantified on CP-I (cNWU) and VNC-I (vNWU). The clinical endpoint was functional independence at discharge. cNWU and vNWU were highly correlated (r = 0.71, p < 0.0001). The median difference between cNWU and vNWU was 8.7% (IQR: 4.5–14.1%), associated with successful vessel recanalization (mTICI2b-3) (ß: 11.6%, 95% CI 2.9–23.0%, p = 0.04), and age (ß: 4.2%, 95% CI 1.3–7.0%, p = 0.005). The diagnostic accuracy to classify outcome between cNWU and vNWU was similar (AUC:0.78 versus 0.77). Although there was an 8.7% median difference, indicating potential edema underestimation on CP-I, it did not have short-term clinical implications. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID-19) pandemic affected the healthcare system in a major way generally. Healthcare re-organization of resources and manpower, establishing management protocols and specific patients' pathways are all evolving with the continuously changing situation. Neuro-vascular management and its re-organization are part of these global measures to cope with this pandemic in a way to establish less risky patients' pathways, help in patients' triage, protecting the staff by introducing training and applying safety measures and to manage neuro-vascular emergencies and elective activity. We here describe the situation of the pandemic affecting neuro-vascular interventions and propose our recommendations for patients' triage, resources management and organization, remote solutions and preparations for any future waves. [ABSTRACT FROM AUTHOR]

Application of contrast agents (CA) is widely used in various clinical fields like oncology. Similar to approaches used in computed tomography, virtual non-contrast enhanced (VNC) images can be generated with the goal to supersede true non-contrast enhanced (TNC) images. In MRI a T1-mapping sequence with variable flip angle (VFA) was used to acquire two images with different image contrast at the same time. To generate VNC images postprocessing based on this technique, an image-space based material decomposition algorithm was used. The inverse of a sensitivity matrix, consisting of intensity values for both VFA images and every material respectively, was used to determine the three material fractions and to calculate the final VNC images. The technique was tested on a 3 T scanner using a phantom and two in-vivo scans of patients with glioma and glioblastoma respectively. In all these cases the required six values were manually derived from the respective material or the background from both VFA images. Postprocessing results of the phantom show that the chosen materials can be separated and visualized individually and unwanted materials can be suppressed. In the VNC images of in-vivo scans the signal of the CA is removed successfully. It was shown that VNC images that match the visual impression of the TNC images can be generated, resulting in possibly reduced scan times and avoided mismatches due to movement of the patient. [ABSTRACT FROM AUTHOR]

Background. Intracerebral hemorrhage (ICH) is a serious complication of endovascular treatment (EVT) in stroke patients with large vessel occlusion (LVO) and associated with increased morbidity and mortality. Aims. Identification of radiological predictors is highly relevant. We investigated the predictive power of computed tomography perfusion (CTP) parameters concerning ICH in patients receiving EVT. Methods. 392 patients with anterior circulation LVO with multimodal CT imaging who underwent EVT were analyzed. CTP parameters were visually evaluated for modified ASPECTS regions and compared between patients without ICH, those with hemorrhagic infarction (HI), and those with parenchymal hematoma (PH) according to the ECASS criteria at follow-up imaging and broken down by ASPECTS regions. Results. 168 received intravenous thrombolysis (IV-rtPA), and 115 developed subsequent ICH (29.3%), of which 74 were classified as HI and 41 as PH. Patients with HI and PH had lower ASPECTS than patients without ICH and worse functional outcome after 90 days (p < 0.05). In 102 of the 115 patients with ICH, the deep middle cerebral artery (MCA) territory was affected with differences between patients without ICH, those with HI, and those with PH regarding cerebral blood volume (CBV) and blood-brain barrier permeability measured as flow extraction product (FED) relative to the contralateral hemisphere (p < 0.05). Patients with PH showed larger perfusion CT infarct core than patients without ICH (p < 0.01). Conclusion. None of the examined CTP parameters was found to be a strong predictor of subsequent ICH. ASPECTS and initial CTP core volume were more reliable and may be useful and even so more practicable to assess the risk of subsequent ICH after EVT. [ABSTRACT FROM AUTHOR]

Objective: Mechanical thrombectomy (MT) is of benefit to patients with ischemic stroke; however, the effect of recanalization on lesion pathophysiology is not yet well understood. The aim of this study was to quantitatively assess how the effect of vessel recanalization on clinical outcome is mediated by edema reduction versus penumbra salvage. Methods: Consecutive analysis was made of anterior circulation ischemic stroke patients triaged by multimodal computed tomography (CT) undergoing MT. Edema reduction was defined using the difference of quantitative net water uptake (NWU) determined on baseline and follow‐up CT (∆NWU). Penumbra salvage volume (PSV) was defined as the difference between admission penumbra and net infarct growth volumes to follow‐up. Mediation analyses were performed with vessel recanalization as independent variable (modified Thrombolysis in Cerebral Infarction ≥ 2b) and ∆NWU/PSV as mediator variables. Modified Rankin Scale scores at 90 days served as endpoint. Results: Of 422 included patients, 321 (76%) achieved successful recanalization. The median ∆NWU was 6.8% (interquartile range [IQR] = 3.9–10.4), and the median PSV was 66ml (IQR = 8–124). ∆NWU, PSV, and recanalization were significantly associated with functional outcome in logistic regression analysis. ∆NWU and PSV partially mediated the relationship between recanalization and outcome. Sixty‐six percent of the relationship between recanalization and functional outcome could be explained by treatment‐induced edema reduction, whereas 22% was mediated by PSV (p < 0.0001). Interpretation: Compared to penumbra salvage, edema reduction was a stronger mediator of the effect of recanalization on functional outcome. Given the current trials on adjuvant neuroprotectants also targeting ischemic edema formation, combining reperfusion with antiedematous neuroprotectants may have synergistic effects resulting in better outcomes in patients with ischemic stroke. ANN NEUROL 2024;95:137–145 [ABSTRACT FROM AUTHOR]

Rationale: Oxygen is essential for cellular energy metabolism. Neurons are particularly vulnerable to hypoxia. Increasing oxygen supply shortly after stroke onset could preserve the ischemic penumbra until revascularization occurs. Aims: PROOF investigates the use of normobaric oxygen (NBO) therapy within 6 h of symptom onset/notice for brain-protective bridging until endovascular revascularization of acute intracranial anterior-circulation occlusion. Methods and design: Randomized (1:1), standard treatment-controlled, open-label, blinded endpoint, multicenter adaptive phase IIb trial. Study outcomes: Primary outcome is ischemic core growth (mL) from baseline to 24 h (intention-to-treat analysis). Secondary efficacy outcomes include change in NIHSS from baseline to 24 h, mRS at 90 days, cognitive and emotional function, and quality of life. Safety outcomes include mortality, intracranial hemorrhage, and respiratory failure. Exploratory analyses of imaging and blood biomarkers will be conducted. Sample size: Using an adaptive design with interim analysis at 80 patients per arm, up to 456 participants (228 per arm) would be needed for 80% power (one-sided alpha 0.05) to detect a mean reduction of ischemic core growth by 6.68 mL, assuming 21.4 mL standard deviation. Discussion: By enrolling endovascular thrombectomy candidates in an early time window, the trial replicates insights from preclinical studies in which NBO showed beneficial effects, namely early initiation of near 100% inspired oxygen during short temporary ischemia. Primary outcome assessment at 24 h on follow-up imaging reduces variability due to withdrawal of care and early clinical confounders such as delayed extubation and aspiration pneumonia. Trial registrations: ClinicalTrials.gov: NCT03500939; EudraCT: 2017-001355-31. [ABSTRACT FROM AUTHOR]

Background: The no-reflow phenomenon refers to the absence of microvascular reperfusion despite macrovascular reperfusion. Aim: The aim of this analysis was to summarize the available clinical evidence on no-reflow in patients with acute ischemic stroke. Methods: A systematic literature review and a meta-analysis of clinical data on definition, rates, and impact of the no-reflow phenomenon after reperfusion therapy was carried out. A predefined research strategy was formulated according to the Population, Intervention, Comparison, and Outcome (PICO) model and was used to screen for articles in PubMed, MEDLINE, and Embase up to 8 September 2022. Whenever possible, quantitative data were summarized using a random-effects model. Results: Thirteen studies with a total of 719 patients were included in the final analysis. Most studies (n = 10/13) used variations of the Thrombolysis in Cerebral Infarction scale to evaluate macrovascular reperfusion, whereas microvascular reperfusion and no-reflow were mostly assessed on perfusion maps (n = 9/13). In one-third of stroke patients with successful macrovascular reperfusion (29%, 95% confidence interval (CI), 21–37%), the no-reflow phenomenon was observed. Pooled analysis showed that no-reflow was consistently associated with reduced rates of functional independence (odds ratio (OR), 0.21, 95% CI, 0.15–0.31). Conclusion: The definition of no-reflow varied substantially across studies, but it appears to be a common phenomenon. Some of the no-reflow cases may simply represent remaining vessel occlusions, and it remains unclear whether no-reflow is an epiphenomenon of the infarcted parenchyma or causes infarction. Future studies should focus on standardizing the definition of no-reflow with more consistent definitions of successful macrovascular reperfusion and experimental set-ups that could detect the causality of the observed findings. [ABSTRACT FROM AUTHOR]

Purpose: Flow arrest using a balloon guide catheter (BGC) in mechanical thrombectomy (MT) due to large vessel occlusion has been associated with better outcomes. Known limitations of currently commercially available BGCs are incompatibility with large bore aspiration catheters (AC) and lack of distal flexibility. Walrus presents variable stiffness and compatibility with large bore AC. The goal of this study is to describe the first experience with Walrus in a realistic stroke simulation model. Methods: A full-length modular vascular model under physiological conditions was used. 8F+-Walrus inner-diameter (ID) 0.087in 95 cm combined with 6F-Sofia AC ID 0.070in 131 cm and an 8F-Flowgate2 BGC ID 0.084in 95 cm with a 5F-Sofia AC ID 0.055in 125 cm were used to perform aspiration MT. User surveys, access to target and occlusion site, technique, time of delivery, anatomical change, and catheter kick-back were assessed. Results: Seven neuroradiologists with average of 10 years-experience in MT performed primary aspiration using the above-mentioned combinations in three different anatomies (N = 41). All operators would likely (29%) or very likely (71%) use again Walrus in combination with large bore AC and the majority (86%) found its navigability easier than with other BGCs. Time to reach final BGC position and catheter kick-back did not differ significantly among anatomies or catheter combinations (p > 0.05). However, Walrus was more likely to reach ICA petrous segment (p < 0.05) and intracranial occlusion with AC (p < 0.01). Conclusion: The Walrus combined with large bore AC presented significantly better distal access and navigability for primary aspiration in an in vitro stroke model. [ABSTRACT FROM AUTHOR]

Background and Purpose: This study was dedicated to investigating the agreement of the calculated results of two CT perfusion (CTP) postprocessing software packages, including parameter maps and ischemic volume, focusing on the infarct core volume (ICV) and penumbra volume (PV). Methods: A retrospective collection of 235 patients with acute ischemic stroke who underwent CTP examination were enrolled. All images had been analyzed with two software pipelines, RAPID CTP and AccuCTP, and the comparative analysis was based on ICV and PV results calculated by both software packages. The agreement of parameter maps was evaluated by root mean square error and Bland‐Altman analysis. The ICV and PV agreement was evaluated by intraclass correlation coefficient (ICC) and Bland‐Altman analysis. The accuracy of ICV and PV based on multiple thresholds was also analyzed. Results: The ICV and PV of AccuCTP and RAPID CTP show excellent agreement. The relative differences of the parameter maps were all within 10% and the Bland‐Altman analysis also showed a strong agreement. From ordinary least squares fitting results, both ICV and PV had a remarkably high goodness of fit (ICV, R2= 0.975 [p<.001]; PV, R2= 0.964 [p<.001]). For the ICC analysis, both had high ICC scores (ICV ICC 0.984, 95% CI [confidence interval] 0.973‐0.989; PV ICC 0.955, 95% CI 0.947‐0.964). Furthermore, multi‐threshold analysis on the basis of ICV and PV also achieved reliable analytical accuracy. Conclusions: The image analysis results of AccuCTP are in excellent agreement with RAPID CTP and can be used as an alternative analysis tool to RAPID CTP software in stroke clinical practice. [ABSTRACT FROM AUTHOR]

Objectives: Non-contrast computed tomography (NCCT) markers are robust predictors of parenchymal hematoma expansion in intracerebral hemorrhage (ICH). We investigated whether NCCT features can also identify ICH patients at risk of intraventricular hemorrhage (IVH) growth. Methods: Patients with acute spontaneous ICH admitted at four tertiary centers in Germany and Italy were retrospectively included from January 2017 to June 2020. NCCT markers were rated by two investigators for heterogeneous density, hypodensity, black hole sign, swirl sign, blend sign, fluid level, island sign, satellite sign, and irregular shape. ICH and IVH volumes were semi-manually segmented. IVH growth was defined as IVH expansion > 1 mL (eIVH) or any delayed IVH (dIVH) on follow-up imaging. Predictors of eIVH and dIVH were explored with multivariable logistic regression. Hypothesized moderators and mediators were independently assessed in PROCESS macro models. Results: A total of 731 patients were included, of whom 185 (25.31%) suffered from IVH growth, 130 (17.78%) had eIVH, and 55 (7.52%) had dIVH. Irregular shape was significantly associated with IVH growth (OR 1.68; 95%CI [1.16–2.44]; p = 0.006). In the subgroup analysis stratified by the IVH growth type, hypodensities were significantly associated with eIVH (OR 2.06; 95%CI [1.48–2.64]; p = 0.015), whereas irregular shape (OR 2.72; 95%CI [1.91–3.53]; p = 0.016) in dIVH. The association between NCCT markers and IVH growth was not mediated by parenchymal hematoma expansion. Conclusions: NCCT features identified ICH patients at a high risk of IVH growth. Our findings suggest the possibility to stratify the risk of IVH growth with baseline NCCT and might inform ongoing and future studies. Clinical relevance statement: Non-contrast CT features identified ICH patients at a high risk of intraventricular hemorrhage growth with subtype-specific differences. Our findings may assist in the risk stratification of intraventricular hemorrhage growth with baseline CT and might inform ongoing and future clinical studies. Key Points: • NCCT features identified ICH patients at a high risk of IVH growth with subtype-specific differences. • The effect of NCCT features was not moderated by time and location or indirectly mediated by hematoma expansion. • Our findings may assist in the risk stratification of IVH growth with baseline NCCT and might inform ongoing and future studies. [ABSTRACT FROM AUTHOR]

Background and purpose: Clinical assessment scores in acute ischemic stroke are only moderately correlated with lesion volume since lesion location is an important confounding factor. Many studies have investigated gray matter indicators of stroke severity, but the understanding of white matter tract involvement is limited in the early phase after stroke. This study aimed to measure and model the involvement of white matter tracts with respect to 24-h post-stroke National Institutes of Health Stroke Scale (NIHSS). Material and methods: A total of 96 patients (50 females, mean age 66.4 ± 14.0 years, median NIHSS 5, interquartile range: 2–9.5) with follow-up fluid-attenuated inversion recovery magnetic resonance imaging data sets acquired one to seven days after acute ischemic stroke onset due to proximal anterior circulation occlusion were included. Lesions were semi-automatically segmented and non-linearly registered to a common reference atlas. The lesion overlap and tract integrity were determined for each white matter tract in the AALCAT atlas and used to model NIHSS outcomes using a supervised linear-kernel support vector regression method, which was evaluated using leave-one-patient-out cross validation. Results: The support vector regression model using the tract integrity and tract lesion overlap measurements predicted the 24-h NIHSS score with a high correlation value of r = 0.7. Using the tract overlap and tract integrity feature improved the modeling accuracy of NIHSS significantly by 6% (p < 0.05) compared to using overlap measures only. Conclusion: White matter tract integrity and lesion load are important predictors for clinical outcome after an acute ischemic stroke as measured by the NIHSS and should be integrated for predictive modeling. [ABSTRACT FROM AUTHOR]

Background/purpose: The benefit of endovascular thrombectomy in acute ischemic stroke (AIS) therapy of proximal large vessel occlusions (LVO) is established. However, there are few prospective studies evaluating the use of a direct aspiration first pass technique in distal vessel occlusions. This post hoc analysis of the PROMISE study examines the safety and effectiveness of the Penumbra System with the ACE68 and ACE64 Reperfusion Catheters for aspiration thrombectomy in the M1 and M2 segments of the middle cerebral artery. Methods: PROMISE is a prospective, multicenter study that enrolled 204 patients with anterior circulation LVO AIS-treated frontline with ACE68/ACE64 catheters. We compared clinical and angiographic outcomes, complications, and mortality in patients with M1 and M2 occlusions. The association of M1 and M2 location and functional independence or mTICI 2b-3 reperfusion was described in univariable and multivariable analyses. Results: One hundred sixty-one patients (124 M1 and 37 M2 locations) met the study criteria. Post procedure mTICI 2b-3 reperfusion (93% vs. 92%, p = 1.00), functional independence (57% vs. 70%, p = 0.18), symptomatic intracranial hemorrhage (1.6% vs. 2.7%, p = 0.55), device- or procedure-related serious adverse events at 30 days (4.0% vs. 8.1%, p = 0.39), and mortality at 90 days (6.6% vs. 2.7%, p = 0.69) were comparable between M1 and M2 occlusions. In multivariable analysis, lower age, lower baseline NIHSS, and shorter time from onset to admission were independent predictors of functional independence. Conclusions: For frontline aspiration thrombectomy of stroke, use of large-bore ACE68/ACE64 catheters for treatment of M2 occlusions appeared as safe and effective as for M1 occlusions. [ABSTRACT FROM AUTHOR]

Mechanical thrombectomy (MT) for acute ischemic stroke with medium vessel occlusions is still a matter of debate. We sought to identify factors associated with clinical outcome after MT for M2-occlusions based on data from the German Stroke Registry-Endovascular Treatment (GSR-ET). All patients prospectively enrolled in the GSR-ET from 05/2015 to 12/2021 were analyzed (NCT03356392). Inclusion criteria were primary M2-occlusions and availability of relevant clinical data. Factors associated with excellent/good outcome (modified Rankin scale mRS 0–1/0–2), poor outcome/death (mRS 5–6) and mRS-increase pre-stroke to day 90 were determined in multivariable logistic regression. 1348 patients were included. 1128(84%) had successful recanalization, 595(44%) achieved good outcome, 402 (30%) had poor outcome. Successful recanalization (odds ratio [OR] 4.27 [95% confidence interval 3.12–5.91], p < 0.001), higher Alberta stroke program early CT score (OR 1.25 [1.18–1.32], p < 0.001) and i.v. thrombolysis (OR 1.28 [1.07–1.54], p < 0.01) increased probability of good outcome, while age (OR 0.95 [0.94–0.95], p < 0.001), higher pre-stroke-mRS (OR 0.36 [0.31–0.40], p < 0.001), higher baseline NIHSS (OR 0.89 [0.88–0.91], p < 0.001), diabetes (OR 0.52 [0.42–0.64], p < 0.001), higher number of passes (OR 0.75 [0.70–0.80], p < 0.001) and intracranial hemorrhage (OR 0.26 [0.14–0.46], p < 0.001) decreased the probability of good outcome. Additional predictors of mRS-increase pre-stroke to 90d were dissections, perforations (OR 1.59 [1.11–2.29], p < 0.05) and clot migration, embolization (OR 1.67 [1.21–2.30], p < 0.01). Corresponding to large-vessel-occlusions, younger age, low pre-stroke-mRS, low severity of acute clinical disability, i.v. thrombolysis and successful recanalization were associated with good outcome while diabetes and higher number of passes decreased probability of good outcome after MT in M2 occlusions. Treatment related complications increased probability of mRS increase pre-stroke to 90d. [ABSTRACT FROM AUTHOR]

Introduction: The aims of this study were to evaluate the relationship of clinical and imaging baseline factors and treatment on the occurrence of early neurological improvement (ENI) in the WAKE-UP trial of MRI-guided intravenous thrombolysis in unknown onset stroke and to examine the association of ENI with long-term favorable outcome in patients treated with intravenous thrombolysis. Methods: We analyzed data from all patients with at least moderate stroke severity, reflected by an initial National Institutes of Health Stroke Scale (NIHSS) score ≥4 randomized in the WAKE-UP trial. ENI was defined as a decrease in NIHSS of ≥8 or a decline to zero or 1 at 24 h after initial presentation to the hospital. Favorable outcome was defined as a modified Rankin Scale score of 0–1 at 90 days. We performed group comparison and multivariable analysis of baseline factors associated with ENI and performed mediation analysis to evaluate the effect of ENI on the relationship between intravenous thrombolysis and favorable outcome. Results: ENI occurred in 93 out of 384 patients (24.2%) and was more likely to occur in patients who received treatment with alteplase (62.4% vs. 46.0%, p = 0.009), had smaller acute diffusion-weighted imaging lesion volume (5.51 mL vs. 10.9 mL, p ≤ 0.001), and less often large-vessel occlusion on initial MRI (7/93 [12.1%] versus 40/291 [29.9%], p = 0.014). In multivariable analysis, treatment with alteplase (OR 1.97, 95% confidence interval [CI] 0.954–1.100), lower baseline stroke volume (OR 0.965, 95% CI: 0.932–0.994), and shorter time from symptom recognition to treatment (OR 0.994, 95% CI: 0.989–0.999) were independently associated with ENI. Patients with ENI had higher rates of favorable outcome at 90-day follow-up (80.6% vs. 31.3%, p ≤ 0.001). The occurrence of ENI significantly mediated the association of treatment with a good outcome, with ENI at 24 h explaining 39.4% (12.9–96%) of the treatment effect. Conclusion: Intravenous alteplase increases the odds of ENI in patients with at least moderate stroke severity, especially when given early. In patients with large-vessel occlusion, ENI is rarely observed without thrombectomy. ENI represents a good surrogate early marker of treatment effect as more than a third of good outcome at 90 days is explained by ENI at 24 h. [ABSTRACT FROM AUTHOR]

Cortical venous outflow (VO) represents an imaging biomarker of increasing interest in patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO). We conducted a retrospective multicenter cohort study to investigate the effect of aging on VO. A total of 784 patients met the inclusion criteria. Cortical Vein Opacification Score (COVES) was used to assess VO profiles on admission CT angiography. Cerebral microperfusion was determined using the hypoperfusion intensity ratio (HIR) derived from perfusion imaging. Arterial collaterals were assessed using the Tan scale. Multivariable regression analysis was performed to identify independent determinants of VO, HIR and arterial collaterals. In multivariable regression, higher age correlated with worse VO (adjusted odds ratio [95% CI]; 0.83 [0.73–0.95]; P = 0.006) and poorer HIR (β coefficient [95% CI], 0.014 [0.005–0.024]; P = 0.002). The negative effect of higher age on VO was mediated by the extent of HIR (17.3%). We conclude that higher age was associated with worse VO in AIS-LVO, partially explained by the extent of HIR reflecting cerebral microperfusion. Our study underlines the need to assess collateral blood flow beyond the arterial system and provides valuable insights into deteriorated cerebral blood supply in elderly AIS-LVO patients. [ABSTRACT FROM AUTHOR]

OBJECTIVES: This study is aimed to determine the location and distribution of pulmonary embolism (PE) and presence of signs potentially indicative of right heart overload on computed tomography pulmonary angiography (CTPA) in COVID-19 and non-COVID-19 patients. We also evaluated the extent and severity of COVID-19-associated lung changes in relation to PE. METHODS: The total number of 1,698 patients with CTPA included in the study were divided into 2 groups according to their COVID-19 status and each group was divided into 2 subgroups based on their PE status. These groups and subgroups were compared in terms of location of PE, diameter of pulmonary artery, right heart strain, ground-glass opacities (GGO), consolidations and other imaging features. RESULTS: In COVID-19 patients, there was a signifi cant predominance of PE in peripheral branches of pulmonary artery (p < 0.001). There was an increased right-to-left ratio of ventricular diameters in cases with PE (p = 0.032 in patients with COVID-19 and p < 0.001 in non-COVID-19 patients). There was no association between the extent and severity of the disease and distribution of PE. CONCLUSION: COVID-19 is associated with a higher incidence of peripheral location of PE and presence of GGO. There were signs indicative of right heart overload in cases with PE regardless of COVID-19 (Tab. 3, Fig. 1, Ref. 29). T ext in PDF www.elis.sk. [ABSTRACT FROM AUTHOR]

Background and purpose: Mechanical thrombectomy (MT) has proven to be the standard of care for patients with acute ischemic stroke due to large vessel occlusion (AIS‐LVO). However, high revascularization rates do not necessarily result in favorable functional outcomes. We aimed to investigate imaging biomarkers associated with futile recanalization, defined as unfavorable functional outcome despite successful recanalization in AIS‐LVO patients. Methods: A retrospective multicenter cohort study was made of AIS‐LVO patients treated by MT. Successful recanalization was defined as modified Thrombolysis in Cerebral Infarction score of 2b–3. A modified Rankin Scale score of 3–6 at 90 days was defined as unfavorable functional outcome. Cortical Vein Opacification Score (COVES) was used to assess venous outflow (VO), and the Tan scale was utilized to determine pial arterial collaterals on admission computed tomography angiography (CTA). Unfavorable VO was defined as COVES ≤ 2. Multivariable regression analysis was performed to investigate vascular imaging factors associated with futile recanalization. Results: Among 539 patients in whom successful recanalization was achieved, unfavorable functional outcome was observed in 59% of patients. Fifty‐eight percent of patients had unfavorable VO, and 31% exhibited poor pial arterial collaterals. In multivariable regression, unfavorable VO was a strong predictor (adjusted odds ratio = 4.79, 95% confidence interval = 2.48–9.23) of unfavorable functional outcome despite successful recanalization. Conclusions: We observe that unfavorable VO on admission CTA is a strong predictor of unfavorable functional outcomes despite successful vessel recanalization in AIS‐LVO patients. Assessment of VO profiles could help as a pretreatment imaging biomarker to determine patients at risk for futile recanalization. [ABSTRACT FROM AUTHOR]

Background and Purpose: Although the role of wall shear stress (WSS) in the initiation, growth, and rupture of intracranial aneurysms has been well studied, its influence on aneurysm recurrence after endovascular treatment requires further investigation. We aimed to compare WSS at necks of recurrent and nonrecurrent aneurysms.Methods: Nine recurrent coil-embolized aneurysms were identified and matched with nine nonrecurrent aneurysms. Patient-specific vessel geometries reconstructed from follow-up 3-D time-of-flight magnetic resonance angiography were analyzed using computational fluid dynamics (CFD) simulations. Absolute WSS and the percentage of abnormally low and high WSS at the aneurysm neck compared to the near artery were measured.Results: The median percentage of abnormal WSS at the aneurysm neck was 49.3% for recurrent and 34.7% for nonrecurrent aneurysms (P = .011). The area under the receiver-operating-characteristic curve for distinguishing these aneurysms according to the percentage of abnormal WSS was .86 (95% CI .62 to .98). The optimal cut-off value of 45.1% resulted in a sensitivity and a specificity of 88.89% (95% CI 51.8% to 99.7%).Conclusion: Our findings indicate that necks of recurrent aneurysms are exposed to abnormal WSS to a larger extent. Abnormal WSS may serve as a metric to distinguish them from nonrecurrent aneurysms with CFD simulations a priori. [ABSTRACT FROM AUTHOR]

In the article the authors discuss the use of off-label products without clinical approval studies. They reviews the case series by Hans Henkes and colleagues, which investigated the treatment of intracranial stenosis with off-label coronary stents. They comment on their preference for medical materials that are tested in controlled multi-center trials or registries.

Background: The objective of this study was to assess the performance of the first publicly available automated 3D segmentation for spontaneous intracerebral hemorrhage (ICH) based on a 3D neural network before and after retraining. Methods: We performed an independent validation of this model using a multicenter retrospective cohort. Performance metrics were evaluated using the dice score (DSC), sensitivity, and positive predictive values (PPV). We retrained the original model (OM) and assessed the performance via an external validation design. A multivariate linear regression model was used to identify independent variables associated with the model's performance. Agreements in volumetric measurements and segmentation were evaluated using Pearson's correlation coefficients (r) and intraclass correlation coefficients (ICC), respectively. With 1040 patients, the OM had a median DSC, sensitivity, and PPV of 0.84, 0.79, and 0.93, compared to thoseo f 0.83, 0.80, and 0.91 in the retrained model (RM). However, the median DSC for infratentorial ICH was relatively low and improved significantly after retraining, at p < 0.001. ICH volume and location were significantly associated with the DSC, at p < 0.05. The agreement between volumetric measurements (r > 0.90, p > 0.05) and segmentations (ICC ≥ 0.9, p < 0.001) was excellent. Conclusion: The model demonstrated good generalization in an external validation cohort. Location-specific variances improved significantly after retraining. External validation and retraining are important steps to consider before applying deep learning models in new clinical settings. [ABSTRACT FROM AUTHOR]

Simple Summary: Discordance and conversion of receptor expressions in metastatic lesions and primary tumors is often observed in patients with brain metastases from breast cancer. Personalized therapy requires continuous monitoring of receptor expressions and dynamic adaptation of applied targeted treatment options. This study sought to evaluate if quantitative MR image features can predict the receptor status of brain metastases from breast cancer using machine learning algorithms. Results indicate that receptor status can be differentiated non-invasively based on routine MR imaging data. The proposed approach could allow non-invasive expression tracking at high frequencies, and may support dynamic treatment optimization for personalized therapies. Discordance and conversion of receptor expressions in metastatic lesions and primary tumors is often observed in patients with brain metastases from breast cancer. Therefore, personalized therapy requires continuous monitoring of receptor expressions and dynamic adaptation of applied targeted treatment options. Radiological in vivo techniques may allow receptor status tracking at high frequencies at low risk and cost. The present study aims to investigate the potential of receptor status prediction through machine-learning-based analysis of radiomic MR image features. The analysis is based on 412 brain metastases samples from 106 patients acquired between 09/2007 and 09/2021. Inclusion criteria were as follows: diagnosed cerebral metastases from breast cancer; histopathology reports on progesterone (PR), estrogen (ER), and human epidermal growth factor 2 (HER2) receptor status; and availability of MR imaging data. In total, 3367 quantitative features of T1 contrast-enhanced, T1 non-enhanced, and FLAIR images and corresponding patient age were evaluated utilizing random forest algorithms. Feature importance was assessed using Gini impurity measures. Predictive performance was tested using 10 permuted 5-fold cross-validation sets employing the 30 most important features of each training set. Receiver operating characteristic areas under the curves of the validation sets were 0.82 (95% confidence interval [0.78; 0.85]) for ER+, 0.73 [0.69; 0.77] for PR+, and 0.74 [0.70; 0.78] for HER2+. Observations indicate that MR image features employed in a machine learning classifier could provide high discriminatory accuracy in predicting the receptor status of brain metastases from breast cancer. [ABSTRACT FROM AUTHOR]

As severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infections have been shown to affect the central nervous system, the investigation of associated alterations of brain structure and neuropsychological sequelae is crucial to help address future health care needs. Therefore, we performed a comprehensive neuroimaging and neuropsychological assessment of 223 nonvaccinated individuals recovered from a mild to moderate SARS-CoV-2 infection (100 female/123 male, age [years], mean ± SD, 55.54 ± 7.07; median 9.7 mo after infection) in comparison with 223 matched controls (93 female/130 male, 55.74 ± 6.60) within the framework of the Hamburg City Health Study. Primary study outcomes were advanced diffusion MRI measures of white matter microstructure, cortical thickness, white matter hyperintensity load, and neuropsychological test scores. Among all 11 MRI markers tested, significant differences were found in global measures of mean diffusivity (MD) and extracellular free water which were elevated in the white matter of post-SARS-CoV-2 individuals compared to matched controls (free water: 0.148 ± 0.018 vs. 0.142 ± 0.017, P < 0.001; MD [10-3 mm²/s]: 0.747 ± 0.021 vs. 0.740 ± 0.020, P < 0.001). Group classification accuracy based on diffusion imaging markers was up to 80%. Neuropsychological test scores did not significantly differ between groups. Collectively, our findings suggest that subtle changes in white matter extracellular water content last beyond the acute infection with SARS-CoV-2. However, in our sample, a mild to moderate SARS-CoV-2 infection was not associated with neuropsychological deficits, significant changes in cortical structure, or vascular lesions several months after recovery. External validation of our findings and longitudinal follow-up investigations are needed. [ABSTRACT FROM AUTHOR]

Purpose: Endovascular treatment of spinal AVMs is limited by low complete cure rates. Transarterial extensive treatment with liquid embolics carries the risk of clinically relevant ischemic complications. We report two cases of symptomatic spinal AVMs treated by a transvenous approach with retrograde pressure cooker technique. Methods: In two selected cases, transvenous navigation aimed at retrograde pressure cooker embolization. Results: Retrograde venous navigation was possible with two parallel microcatheters, and the pressure cooker technique with ethylenvinylalcohol-polymer was applicable in both cases. One AVM was occluded completely, and one subtotally due to a second draining vein. No clinical complications occurred. Conclusion: A transvenous approach for embolization with liquid embolics may offer advantages in treating certain spinal AVMs. [ABSTRACT FROM AUTHOR]

Background: (1) Description of clinical and cranial MRI features in the original Pontine Autosomal Dominant Microangiopathy with Leukoencephalopathy (PADMAL) family and correlation with the segregation analysis of the causative collagen 4A1 gene (COL4A1) variant. (2) Sequence analysis of the COL4A1 miRNA-binding site containing the causative variant in two independent cross-sectional samples of sporadic stroke patients. Patients and methods: Sanger sequencing of the COL4A1 miRNA-binding site in the PADMAL family and 874 sporadic stroke patients. Results: PADMAL shows adult-onset usually between 30 and 50 years of age with initial brainstem-related symptoms most commonly dysarthria, with progression to dementia and tetraparesis. Radiologically pontine lacunes are followed by supratentorial white matter involvement. Radiological onset may precede clinical symptoms. We found no variants in the COL4A1 miRNA-binding site of sporadic stroke patients. Conclusion: Our results allow an early diagnosis of PADMAL based on cranial MRI, clinical signs, and confirmatory sequencing of the COL4A1 miRNA-29-binding site. COL4A1 miRNA-29-binding site variants do not contribute to a sizeable proportion of sporadic stroke. [ABSTRACT FROM AUTHOR]

Objective: Automated brain volumetric analysis based on high-resolution T1-weighted MRI datasets is a frequently used tool in neuroimaging for early detection, diagnosis, and monitoring of various neurological diseases. However, image distortions can corrupt and bias the analysis. The aim of this study was to explore the variability of brain volumetric analysis due to gradient distortions and to investigate the effect of distortion correction methods implemented on commercial scanners. Material and methods: 36 healthy volunteers underwent brain imaging using a 3T magnetic resonance imaging (MRI) scanner, including a high-resolution 3D T1-weighted sequence. For all participants, each T1-weighted image was reconstructed directly on the vendor workstation with (DC) and without (nDC) distortion correction. For each participant's set of DC and nDC images, FreeSurfer was used for the determination of regional cortical thickness and volume. Results: Overall, significant differences were found in 12 cortical ROIs comparing the volumes of the DC and nDC data and in 19 cortical ROIs comparing the thickness of the DC and nDC data. The most pronounced differences for cortical thickness were found in the precentral gyrus, the lateral occipital and postcentral ROI (2.69, -2.91% and -2.79%, respectively) while cortical volumes differed most prominently in the paracentral, the pericalcarine and lateral occipital ROI (5.52%, -5.40% and -5.11%, respectively). Conclusion: Correcting for gradient non-linearities can have significant influence on volumetric analysis of cortical thickness and volume. Since the distortion correction is an automatic feature of the MR scanner, it should be stated by each study that applies volumetric analysis which images were used. [ABSTRACT FROM AUTHOR]

Objective: Intracerebral hemorrhage (ICH) has a high mortality and long-term morbidity and thus has a significant overall health–economic impact. Outcomes are especially poor if the exact onset is unknown, but reliable imaging-based methods for onset estimation have not been established. We hypothesized that onset prediction of patients with ICH using artificial intelligence (AI) may be more accurate than human readers. Material and Methods: A total of 7421 computed tomography (CT) datasets between January 2007–July 2021 from the University Hospital Basel with confirmed ICH were extracted and an ICH-segmentation algorithm as well as two classifiers (one with radiomics, one with convolutional neural networks) for onset estimation were trained. The classifiers were trained based on the gold standard of 644 datasets with a known onset of >1 and <48 h. The results of the classifiers were compared to the ratings of two radiologists. Results: Both the AI-based classifiers and the radiologists had poor discrimination of the known onsets, with a mean absolute error (MAE) of 9.77 h (95% CI (confidence interval) = 8.52–11.03) for the convolutional neural network (CNN), 9.96 h (8.68–11.32) for the radiomics model, 13.38 h (11.21–15.74) for rater 1 and 11.21 h (9.61–12.90) for rater 2, respectively. The results of the CNN and radiomics model were both not significantly different to the mean of the known onsets (p = 0.705 and p = 0.423). Conclusions: In our study, the discriminatory power of AI-based classifiers and human readers for onset estimation of patients with ICH was poor. This indicates that accurate AI-based onset estimation of patients with ICH based only on CT-data may be unlikely to change clinical decision making in the near future. Perhaps multimodal AI-based approaches could improve ICH onset prediction and should be considered in future studies. [ABSTRACT FROM AUTHOR]

Objectives: Flat-panel CT (FPCT) allows cross-sectional parenchymal, vascular and perfusion imaging within the angiography suite, which could greatly facilitate acute stroke management. We hypothesized that FPCT offers equal diagnostic accuracy compared to multi-detector CT (MDCT) as a primary tool to exclude intracranial hemorrhage. Methods: 22 patients with intracranial hematomas who had both MDCT and FPCT performed within 24 hours were retrospectively identified. Patients with visible change in hematoma size or configuration were excluded. Two raters independently segmented hemorrhagic lesions. Data sets and corresponding binary lesion maps were co-registered to compare hematoma volume. Diagnostic accuracy of FPCT to detect hemorrhage was calculated from voxel-wise analysis of lesion overlap compared to reference MDCT. Results: Mean hematoma size was similar between MDCT (16.2±8.9 ml) and FPCT (16.1±8.6 ml), with near perfect correlation of hematoma sizes between modalities (ρ = 0.95, p<0.001). Sensitivity and specificity of FPCT to detect hemorrhagic voxels was 61.6% and 99.8% for intraventricular hematomas and 67.7% and 99.5% for all other intracranial hematomas. Conclusions: In this small sample containing predominantly cases with subarachnoid hemorrhage, FPCT based assessment of hemorrhagic volume in brain yields acceptable accuracy compared to reference MDCT, albeit with a limited sensitivity on a voxel level. Further assessment and improvement of FPCT is necessary before it can be applied as a primary imaging modality to exclude intracranial hemorrhage in acute stroke patients. [ABSTRACT FROM AUTHOR]