Time to Go Augmented in Vascular Interventional Neuroradiology?

International audienceThis editorial paper reports on our experience in introducing augmented reality (AR) in interventional neuroradiology environments. Our expectations about the next AR tools, in particular for more advanced visualization, are also put forward. For practical reasons, the references will be restricted to our contributions. For further information, the last recommendations concerning the medical management of aneurysm induced hemorrhages can be found in [connolly12

The Use of 3D Xray angiographic Images for Volume Determination of Cerebral Arteriovenous Malformations

Colloque avec actes et comité de lecture. internationale.International audienceThe radiotherapic treatment of cerebral arterious malformations (AVM) requires an accurate estimation of the AVM shape. This estimation is classically obtained from the delineation of the AVM in several 2D angiographic views. In this paper, a clinical study of the inter-observer variability in the AVM detection is first performed. It proves that the estimated volume varies a lot between observers. For these reasons, we propose a framework for AVM delineation which makes use of 2D and 3D angiographic images: the initial estimate obtained with 2D angiographic images is then refined within the 3D volume using deformable models. Results are presented demonstrating shape delineation on various AVMs

Model of a Vascular C-Arm for 3D Augmented Fluoroscopy in Interventional Radiology

International audienceThis paper deals with the modeling of a vascular C-arm to generate 3D augmented fuoroscopic images in an interventional radiology context. A methodology based on the use of a multi-image calibration is proposed to assess the physical behavior of the C-arm. From the knowledge of the main characteristics of the C-arm, realistic models of the acquisition geometry are proposed. Their accuracy was evaluated and experiments showed that the C-arm geometry can be predicted with a mean 2D reprojection error of 0.5 mm. The interest of 3D augmented uoroscopy is also assessed on a clinical case

Evaluation of a computer-based simulation for the endovascular treatment of intracranial aneurysms

International audiencePurpose: Endovascular treatment (EVT) of intracranial aneurysms requires highly trained physicians and careful pre-therapeutic evaluation of the aneurysm morphology. A realistic interventional neuroradiology simulator would provide procedural and skill training for either educational purpose or pre-therapeutic simulation in complex cases. This work aims at evaluating the clinical realism of a computer-based simulator for the EVT of aneurysms. Material and Methods: A prototype computer-based EVT simulation system was developed and implemented. A silicon vascular phantom (Elastrat, Geneva, Switzerland) as well as two patient data sets were used for the evaluation. A coil adapted to the aneurysm was deployed under fluoroscopy. Then, a simulation was done with the same, as well as larger and smaller coils under the same viewing incidence and was visually assessed and compared to fluoroscopic images. The maximum of coil pressure onto the aneurysm sac was recorded during all simulations. Results: In all cases, simulation with the correct coil showed a realistic coil behaviour and aneurysm filling. As expected, full and stable coiling of the aneurysm was impossible to simulate with too small coils. Protrusions outside the sac were observed with too large coils. In this latter case, the pressure onto the aneurysm wall dramatically increased as compared with the correct coil. Conclusion: A preliminary evaluation of a computer-based EVT simulation system was made on both phantom and patient data. Our report emphasizes the clinical realism of the simulated deployment of coils, in particular with regard to potential hazards related to an inadequate choice of coil

Une stratégie efficace de préparation des données pour la détection des anévrismes cérébraux en IRM 3D-TOF par deep learning

National audienceLa détection des anévrismes intracrâniens non rompus en IRM 3D-TOF représente une véritable difficulté en pratique clinique. Bien que l'utilisation récente des réseaux de neurones convolutifs (CNN) dans ce domaine ait apporté des résultats prometteurs, une des problématiques fondamentales reste celle du déséquilibre majeur des classes (rareté des anévrismes en termes de voxel par rapport au reste du volume). Jusqu’à présent, les méthodologies décrites dans la littérature se sont concentrées sur les architectures des réseaux. Ce travail aborde la préparation des données en amont

Radiosurgical planning of brain arteriovenous malformations (AVMS): A user interface for the delineation of 3D target from 2D angiographic projections

International audienceA precise delination of the target is a critical part of radiosurgical treatment planning of brain AVMs. This target delineation is performed by drawing the contours of the nidus, the active part of the AVM, on calibrated (using a stereotactic frame) digital subtraction angiography (DSA) projections assuming that DSA remains the imaging gold standard. This manual delineation is a difficult and time consuming task. Inconsistency between the delineations performed in the different views, usually AP and lateral, may led to a wrong target and so on to a poor anatomical result. The aims of this study are 1) to describe an original and helpful user interface to delineate a 3D target by drawing its contours on multiple 2D projections from DSA; 2) to validate the interest of this interface

A methodology for validating a 3D imaging modality for brain AVM delineation: Application to 3DRA.

International audienceA general methodology is described to validate a 3D imaging modality with respect to 2D digital subtracted angiography (DSA) for brain AVMs (BAVM) delineation. It relies on the assessment of the statistical compatibility of the radiosurgical target delineated in 3D with its delineations in 2D. This methodology is demonstrated through a preliminary evaluation of rotational 3D angiography (3DRA). Generally speaking, BAVM delineation cannot be performed on 3DRA alone. However, in our study, 3DRA showed similar performances to DSA for rather easy cases, and even better for 3 patients. Conversely, 3 problematic cases are identified and discussed

Intra- and inter-observer variability in the angiographic delineation of brain arterio-venous malformations (AVMs)

Colloque avec actes et comité de lecture. internationale.International audienceThe purpose of this study is to determine the intra- and inter-observer variability in the manual delineation of the boundaries of brain arterio-venous malformations (AVMs) on digital subtracted angiograms. Such delineation is used to define the target volume in stereotactic radiotherapy

Impact of Emergent Cervical Carotid Stenting in Tandem Occlusion Strokes Treated by Thrombectomy: A Review of the TITAN Collaboration

Introduction: Endovascular therapy has been shown to be an effective and safe treatment for tandem occlusion. The endovascular therapeutic strategies for tandem occlusions strokes have not been adequately evaluated and the best approach is still controversial. The TITAN (Thrombectomy in TANdem occlusions) registry was a result of a collaborative effort to identify the best therapeutic approach for acute ischemic stroke due to tandem lesion. In this review, we aim to summarize the main findings of the TITAN study and discuss the challenges of treatment for tandem occlusion in the era of endovascular thrombectomy.Methods: A review of the data from the multicenter international observational and non-randomized TITAN registry was performed. The TITAN registry included acute ischemic stroke patients with tandem lesions (proximal intracranial occlusion and cervical carotid artery occlusion or stenosis>90%) who were treated with thrombectomy with or without carotid artery stenting.Results: Prior intravenous thrombolysis and emergent cervical carotid stenting were associated with higher reperfusion (mTICI 2b-3 and mTICI 3) rates at the end of the intervention. Poor outcome did not occur more frequently after stenting than after conservative treatment of the cervical carotid lesion. Emergent carotid stenting with antithrombotic agents and intracranial thrombectomy yielded higher reperfusion rate and good outcome (90 day mRS 0–2) compared to other strategies (carotid artery stenting and thrombectomy without antithrombotic, angioplasty and thrombectomy, or thrombectomy alone). Pretreatment intravenous thrombolysis was not associated with increased risk of hemorrhagic complications. Likewise, periprocedural unfractionated heparin did not modify the efficacy and safety results. Etiology of carotid artery lesion (atherosclerosis vs. dissection) did not emerge as predictor of outcome or recanalization.Conclusion: Emergent stenting of the cervical carotid lesion with antithrombotic agents in conjunction to thrombectomy appears to be the best treatment strategy for acute ischemic strokes with tandem lesions. These findings will be further investigated in the ongoing randomized controlled TITAN trial

Imaging features and safety and efficacy of endovascular stroke treatment: a meta-analysis of individual patient-level data

Background: Evidence regarding whether imaging can be used effectively to select patients for endovascular thrombectomy (EVT) is scarce. We aimed to investigate the association between baseline imaging features and safety and efficacy of EVT in acute ischaemic stroke caused by anterior large-vessel occlusion. Methods: In this meta-analysis of individual patient-level data, the HERMES collaboration identified in PubMed seven randomised trials in endovascular stroke that compared EVT with standard medical therapy, published between Jan 1, 2010, and Oct 31, 2017. Only trials that required vessel imaging to identify patients with proximal anterior circulation ischaemic stroke and that used predominantly stent retrievers or second-generation neurothrombectomy devices in the EVT group were included. Risk of bias was assessed with the Cochrane handbook methodology. Central investigators, masked to clinical information other than stroke side, categorised baseline imaging features of ischaemic change with the Alberta Stroke Program Early CT Score (ASPECTS) or according to involvement of more than 33% of middle cerebral artery territory, and by thrombus volume, hyperdensity, and collateral status. The primary endpoint was neurological functional disability scored on the modified Rankin Scale (mRS) score at 90 days after randomisation. Safety outcomes included symptomatic intracranial haemorrhage, parenchymal haematoma type 2 within 5 days of randomisation, and mortality within 90 days. For the primary analysis, we used mixed-methods ordinal logistic regression adjusted for age, sex, National Institutes of Health Stroke Scale score at admission, intravenous alteplase, and time from onset to randomisation, and we used interaction terms to test whether imaging categorisation at baseline modifies the association between treatment and outcome. This meta-analysis was prospectively designed by the HERMES executive committee but has not been registered. Findings: Among 1764 pooled patients, 871 were allocated to the EVT group and 893 to the control group. Risk of bias was low except in the THRACE study, which used unblinded assessment of outcomes 90 days after randomisation and MRI predominantly as the primary baseline imaging tool. The overall treatment effect favoured EVT (adjusted common odds ratio [cOR] for a shift towards better outcome on the mRS 2·00, 95% CI 1·69–2·38; p<0·0001). EVT achieved better outcomes at 90 days than standard medical therapy alone across a broad range of baseline imaging categories. Mortality at 90 days (14·7% vs 17·3%, p=0·15), symptomatic intracranial haemorrhage (3·8% vs 3·5%, p=0·90), and parenchymal haematoma type 2 (5·6% vs 4·8%, p=0·52) did not differ between the EVT and control groups. No treatment effect modification by baseline imaging features was noted for mortality at 90 days and parenchymal haematoma type 2. Among patients with ASPECTS 0–4, symptomatic intracranial haemorrhage was seen in ten (19%) of 52 patients in the EVT group versus three (5%) of 66 patients in the control group (adjusted cOR 3·94, 95% CI 0·94–16·49; pinteraction=0·025), and among patients with more than 33% involvement of middle cerebral artery territory, symptomatic intracranial haemorrhage was observed in 15 (14%) of 108 patients in the EVT group versus four (4%) of 113 patients in the control group (4·17, 1·30–13·44, pinteraction=0·012). Interpretation: EVT achieves better outcomes at 90 days than standard medical therapy across a broad range of baseline imaging categories, including infarcts affecting more than 33% of middle cerebral artery territory or ASPECTS less than 6, although in these patients the risk of symptomatic intracranial haemorrhage was higher in the EVT group than the control group. This analysis provides preliminary evidence for potential use of EVT in patients with large infarcts at baseline. Funding: Medtronic