Imagerie Adaptative Diagnostique et Interventionnelle

BACKGROUND: Cytoreductive nephrectomy has been the standard of care in metastatic renal-cell carcinoma for 20 years, supported by randomized trials and large, retrospective studies. However, the efficacy of targeted therapies has challenged this standard. We assessed the role of nephrectomy in patients with metastatic renal-cell carcinoma who were receiving targeted therapies. METHODS: In this phase 3 trial, we randomly assigned, in a 1:1 ratio, patients with confirmed metastatic clear-cell renal-cell carcinoma at presentation who were suitable candidates for nephrectomy to undergo nephrectomy and then receive sunitinib (standard therapy) or to receive sunitinib alone. Randomization was stratified according to prognostic risk (intermediate or poor) in the Memorial Sloan Kettering Cancer Center prognostic model. Patients received sunitinib at a dose of 50 mg daily in cycles of 28 days on and 14 days off every 6 weeks. The primary end point was overall survival. RESULTS: A total of 450 patients were enrolled from September 2009 to September 2017. At this planned interim analysis, the median follow-up was 50.9 months, with 326 deaths observed. The results in the sunitinib-alone group were noninferior to those in the nephrectomy-sunitinib group with regard to overall survival (stratified hazard ratio for death, 0.89; 95% confidence interval, 0.71 to 1.10; upper boundary of the 95% confidence interval for noninferiority, ≤1.20). The median overall survival was 18.4 months in the sunitinib-alone group and 13.9 months in the nephrectomy-sunitinib group. No significant differences in response rate or progression-free survival were observed. Adverse events were as anticipated in each group. CONCLUSIONS: Sunitinib alone was not inferior to nephrectomy followed by sunitinib in patients with metastatic renal-cell carcinoma who were classified as having intermediate-risk or poor-risk disease. (Funded by Assistance Publique-Hôpitaux de Paris and others; CARMENA ClinicalTrials.gov number, NCT00930033 .).

Abstract We consider the rheological behaviour of felsic magma in the zone of partial melting and during subsequent crystallization. We also introduce and combine concepts (mushy zone, percolation theory, granular flow, shear localization) derived from the non-geological literature and apply them to field observations on migmatites and granites. Segregation and transportation of felsic magmas is commonly observed in association with non-coaxial deformation, suggesting that gravity forces have limited influence during magma segregation. Solid to liquid and liquid to solid transitions are shown to be rheologically different, which infirms the concept of a unique rheological critical melt percentage for both transitions. Four stages are examined, which depend on the melt fraction present. (1) A minimum of 8% melt by volume must first be produced to overcome the liquid percolation threshold (LPT) above which melt pockets can connect, thus allowing local magma displacement. Transport of the liquid phase is amplified by deformation toward dilatant sinks and is restricted to a very local scale. This corresponds to partially molten domains illustrated by incipient migmatites. (2) When more melt (20–25%) is present, a melt escape threshold (MET) allows segregation and transport of the melt and part of the residual solid phase, over large distances. This corresponds to segregation and transfer of magma towards the upper crust. (3) Segregation of magma also occurs during granite emplacement and crystallization. In a flowing magma containing few particles (≤20%), particles rotate independently within the flow, defining a fabric. As soon as sufficient crystals are formed, they interact to construct a rigid skeleton. Such a random loose packed framework involves ∼55% solids and corresponds to the rigid percolation threshold (RPT). Above the RPT, clusters of particles can sustain stress, and the liquid fraction can still flow. The only remaining possibilities for rearranging particles are local shear zones, often within the intrusion rim, which, as a consequence, develops dilatancy. This stage of segregation during crystallization is totally different from that of magma segregation during incipient melting. (4) Finally, the system becomes totally locked when random close packing is reached, at ∼72–75% solidification; this is the particle locking threshold (PLT). The introduction of four thresholds must be viewed in the context of a two-fold division of the cycle that generates igneous rocks, first involving a transition from solid to liquid (i.e. partial melting) and then a transition from liquid to solid (i.e. crystallization). Neither transition is simply the reverse of the other. In the case of melting, pockets of melt have to be connected to afford a path to escaping magma. This is a bond-percolation, in the sense of physical percoloation theory. In the case of crystallization, randomly distributed solid particles mechanically interact, and contacts between them can propagate forces. Building a crystal framework is a site-percolation, for which the threshold is higher than that of bond-percolation. For each transition two thresholds are applicable. The present approach, which basically differs from that based on a unique critical melt fraction, expands and clarifies the idea of a first and a second percolation threshold. One threshold in each transition (LPT and RPT, respectively) corresponds to a percolation threshold in the sense of physical percolation theory. Its value is independent of external forces, but relies on the type and abundance of minerals forming the matrix within which melt connectivity is developing. The exact value of the second threshold (MET or PLT) will vary according to external forces, such as deformation and the particle shape.

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

BACKGROUND: CT perfusion (CTP) and diffusion or perfusion MRI might assist patient selection for endovascular thrombectomy. We aimed to establish whether imaging assessments of irreversibly injured ischaemic core and potentially salvageable penumbra volumes were associated with functional outcome and whether they interacted with the treatment effect of endovascular thrombectomy on functional outcome. METHODS: /s. Critically hypoperfused tissue was estimated as the volume of tissue with a CTP time to maximum longer than 6 s. Mismatch volume (ie, the estimated penumbral volume) was calculated as critically hypoperfused tissue volume minus ischaemic core volume. The association of ischaemic core and penumbral volumes with 90-day mRS score was analysed with multivariable logistic regression (functional independence, defined as mRS score 0-2) and ordinal logistic regression (functional improvement by at least one mRS category) in all patients and in a subset of those with more than 50% endovascular reperfusion, adjusted for baseline prognostic variables. The meta-analysis was prospectively designed by the HERMES executive committee, but not registered. FINDINGS: =0·94). Mismatch volume, examined only in the CTP group because of the small numbers of patients who had perfusion MRI, was not associated with either functional independence or functional improvement. In patients with CTP with more than 50% endovascular reperfusion (n=186), age, ischaemic core volume, and imaging-to-reperfusion time were independently associated with functional improvement. Risk of bias between studies was generally low. INTERPRETATION: Estimated ischaemic core volume was independently associated with functional independence and functional improvement but did not modify the treatment benefit of endovascular thrombectomy over standard medical therapy for improved functional outcome. Combining ischaemic core volume with age and expected imaging-to-reperfusion time will improve assessment of prognosis and might inform endovascular thrombectomy treatment decisions. FUNDING: Medtronic.

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: =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.

Knowledge of whole heart anatomy is a prerequisite for many clinical applications. Whole heart segmentation (WHS), which delineates substructures of the heart, can be very valuable for modeling and analysis of the anatomy and functions of the heart. However, automating this segmentation can be challenging due to the large variation of the heart shape, and different image qualities of the clinical data. To achieve this goal, an initial set of training data is generally needed for constructing priors or for training. Furthermore, it is difficult to perform comparisons between different methods, largely due to differences in the datasets and evaluation metrics used. This manuscript presents the methodologies and evaluation results for the WHS algorithms selected from the submissions to the Multi-Modality Whole Heart Segmentation (MM-WHS) challenge, in conjunction with MICCAI 2017. The challenge provided 120 three-dimensional cardiac images covering the whole heart, including 60 CT and 60 MRI volumes, all acquired in clinical environments with manual delineation. Ten algorithms for CT data and eleven algorithms for MRI data, submitted from twelve groups, have been evaluated. The results showed that the performance of CT WHS was generally better than that of MRI WHS. The segmentation of the substructures for different categories of patients could present different levels of challenge due to the difference in imaging and variations of heart shapes. The deep learning (DL)-based methods demonstrated great potential, though several of them reported poor results in the blinded evaluation. Their performance could vary greatly across different network structures and training strategies. The conventional algorithms, mainly based on multi-atlas segmentation, demonstrated good performance, though the accuracy and computational efficiency could be limited. The challenge, including provision of the annotated training data and the blinded evaluation for submitted algorithms on the test data, continues as an ongoing benchmarking resource via its homepage (www.sdspeople.fudan.edu.cn/zhuangxiahai/0/mmwhs/).

An automated algorithm to assess electrocardiogram (ECG) quality for both normal and abnormal rhythms is presented for false arrhythmia alarm suppression of intensive care unit (ICU) monitors. A particular focus is given to the quality assessment of a wide variety of arrhythmias. Data from three databases were used: the Physionet Challenge 2011 dataset, the MIT-BIH arrhythmia database, and the MIMIC II database. The quality of more than 33 000 single-lead 10 s ECG segments were manually assessed and another 12 000 bad-quality single-lead ECG segments were generated using the Physionet noise stress test database. Signal quality indices (SQIs) were derived from the ECGs segments and used as the inputs to a support vector machine classifier with a Gaussian kernel. This classifier was trained to estimate the quality of an ECG segment. Classification accuracies of up to 99% on the training and test set were obtained for normal sinus rhythm and up to 95% for arrhythmias, although performance varied greatly depending on the type of rhythm. Additionally, the association between 4050 ICU alarms from the MIMIC II database and the signal quality, as evaluated by the classifier, was studied. Results suggest that the SQIs should be rhythm specific and that the classifier should be trained for each rhythm call independently. This would require a substantially increased set of labeled data in order to train an accurate algorithm.

UNLABELLED: Differences in the performance of cadmium-zinc-telluride (CZT) cameras or collimation systems that have recently been commercialized for myocardial SPECT remain unclear. In the present study, the performance of 3 of these systems was compared by a comprehensive analysis of phantom and human SPECT images. METHODS: We evaluated the Discovery NM 530c and DSPECT CZT cameras, as well as the Symbia Anger camera equipped with an astigmatic (IQ x SPECT) or parallel-hole (conventional SPECT) collimator. Physical performance was compared on reconstructed SPECT images from a phantom and from comparable groups of healthy subjects. RESULTS: Classifications were as follows, in order of performance. For count sensitivity on cardiac phantom images (counts x s(-1) x MBq(-1)), DSPECT had a sensitivity of 850; Discovery NM 530c, 460; IQ x SPECT, 390; and conventional SPECT, 130. This classification was similar to that of myocardial counts normalized to injected activities from human images (respective mean values, in counts x s(-1) x MBq(-1): 11.4 ± 2.6, 5.6 ± 1.4, 2.7 ± 0.7, and 0.6 ± 0.1). For central spatial resolution: Discovery NM 530c was 6.7 mm; DSPECT, 8.6 mm; IQ x SPECT, 15.0 mm; and conventional SPECT, 15.3 mm, also in accordance with the analysis of the sharpness of myocardial contours on human images (in cm(-1): 1.02 ± 0.17, 0.92 ± 0.11, 0.64 ± 0.12, and 0.65 ± 0.06, respectively). For contrast-to-noise ratio on the phantom: Discovery NM 530c had a ratio of 4.6; DSPECT, 4.1; IQ x SPECT, 3.9; and conventional SPECT, 3.5, similar to ratios documented on human images (5.2 ± 1.0, 4.5 ± 0.5, 3.9 ± 0.6, and 3.4 ± 0.3, respectively). CONCLUSION: The performance of CZT cameras is dramatically higher than that of Anger cameras, even for human SPECT images. However, CZT cameras differ in that spatial resolution and contrast-to-noise ratio are better with the Discovery NM 530c, whereas count sensitivity is markedly higher with the DSPECT.

BACKGROUND: An accurate estimation of the risk of life-threatening (LT) ventricular tachyarrhythmia (VTA) in patients with LMNA mutations is crucial to select candidates for implantable cardioverter-defibrillator implantation. METHODS: We included 839 adult patients with LMNA mutations, including 660 from a French nationwide registry in the development sample, and 179 from other countries, referred to 5 tertiary centers for cardiomyopathies, in the validation sample. LTVTA was defined as (1) sudden cardiac death or (2) implantable cardioverter defibrillator-treated or hemodynamically unstable VTA. The prognostic model was derived using the Fine-Gray regression model. The net reclassification was compared with current clinical practice guidelines. The results are presented as means (SD) or medians [interquartile range]. RESULTS: We included 444 patients, 40.6 (14.1) years of age, in the derivation sample and 145 patients, 38.2 (15.0) years, in the validation sample, of whom 86 (19.3%) and 34 (23.4%) experienced LTVTA over 3.6 [1.0-7.2] and 5.1 [2.0-9.3] years of follow-up, respectively. Predictors of LTVTA in the derivation sample were: male sex, nonmissense LMNA mutation, first degree and higher atrioventricular block, nonsustained ventricular tachycardia, and left ventricular ejection fraction (https://lmna-risk-vta.fr). In the derivation sample, C-index (95% CI) of the model was 0.776 (0.711-0.842), and the calibration slope 0.827. In the external validation sample, the C-index was 0.800 (0.642-0.959), and the calibration slope was 1.082 (95% CI, 0.643-1.522). A 5-year estimated risk threshold ≥7% predicted 96.2% of LTVTA and net reclassified 28.8% of patients with LTVTA in comparison with the guidelines-based approach. CONCLUSIONS: In comparison with the current standard of care, this risk prediction model for LTVTA in laminopathies significantly facilitated the choice of candidates for implantable cardioverter defibrillators. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03058185.

AIMS: Increased left ventricular wall thickness (LVWT) is a common finding in cardiology. It is not known how often hereditary transthyretin-related familial amyloid cardiomyopathy (mTTR-FAC) is responsible for LVWT. Several therapeutic modalities for mTTR-FAC are currently in clinical trials; thus, it is important to establish the prevalence of TTR mutations (mTTR) and the clinical characteristics of the patients with mTTR-FAC. METHODS AND RESULTS: In a prospective multicentre, cross-sectional study, the TTR gene was sequenced in 298 consecutive patients diagnosed with increased LVWT in primary cardiology clinics in France. Among the included patients, median (25-75th percentiles) age was 62 [50;74]; 74% were men; 23% were of African origin; and 36% were in NYHA Class III-IV. Median LVWT was 18 (16-21) mm. Seventeen (5.7%; 95% confidence interval [CI]: [3.4;9.0]) patients had mTTR of whom 15 (5.0%; 95% CI [2.9;8.2]) had mTTR-FAC. The most frequent mutations were V142I (n = 8), V50M (n = 2), and I127V (n = 2). All mTTR-FAC patients were older than 63 years with a median age of 74 [69;79]. Of the 15 patients with mTTR-FAC, 8 were of African descent while 7 were of European descent. In the African descendants, mTTR-FAC median age was 74 [72;79] vs. 55 [46;65] years in non-mTTR-FAC (P < 0.001). In an adjusted multivariate model, African origin, neuropathy, carpal tunnel syndrome, electrocardiogram (ECG) low voltage, and late gadolinium enhancement (LGE) at cardiac-magnetic resonance imaging were all independently associated with mTTR-FAC. CONCLUSION: Five per cent of patients diagnosed with hypertrophic cardiomyopathy have mTTR-FAC. Mutated transthyretin genetic screening is warranted in elderly subjects with increased LVWT, particularly, those of African descent with neuropathy, carpal tunnel syndrome, ECG low voltage, or LGE.

BACKGROUND: : Most ecologic studies of environmental equity show that groups with lower socioeconomic status (SES) are more likely to be exposed to higher air pollution levels than groups of higher SES. However, these studies rarely consider spatial autocorrelation in the data. We investigated the associations between traffic-related air pollution and SES on a small-area level in Strasbourg (France) and assessed the impact of spatial autocorrelation on the results. METHODS: : We used a deprivation index, constructed from census data, to estimate SES at the block level. Average ambient nitrogen dioxide (NO2) levels during year 2000, modeled at the block level by a dispersion model, served as a marker of traffic exhaust. We estimated the association between exposure to NO2 and the deprivation index by using an ordinary least squares model and a simultaneous autoregressive model that controls for the spatial autocorrelation of data. RESULTS: : The association between the deprivation index and NO2 levels was positive and nonlinear with both regression models; the midlevel deprivation areas were the most exposed. Control of spatial autocorrelation strongly reduced the strength of the association but clearly improved the model's goodness-of-fit; the most pronounced reduction was observed for the midlevel deprivation areas (regression coefficients decreased by 67%). CONCLUSIONS: : This study confirms the need to take spatial autocorrelation into account in ecologic studies and shows that failure to do so may lead to biased and unreliable estimates and thus to erroneous conclusions. This may be especially important in studying the role of air pollution on social inequalities in health.

Built on top of the Geant4 toolkit, GATE is collaboratively developed for more than 15 years to design Monte Carlo simulations of nuclear-based imaging systems. It is, in particular, used by researchers and industrials to design, optimize, understand and create innovative emission tomography systems. In this paper, we reviewed the recent developments that have been proposed to simulate modern detectors and provide a comprehensive report on imaging systems that have been simulated and evaluated in GATE. Additionally, some methodological developments that are not specific for imaging but that can improve detector modeling and provide computation time gains, such as Variance Reduction Techniques and Artificial Intelligence integration, are described and discussed.

Acute appendicitis (AA) is a common abdominal emergency with a lifetime prevalence of about 7 %. As the clinical diagnosis of AA remains a challenge to emergency physicians and surgeons, imaging modalities have gained major importance in the diagnostic work-up of patients with suspected AA in order to keep both the negative appendectomy rate and the perforation rate low. Introduced in 1986, graded-compression ultrasound (US) has well-established direct and indirect signs for diagnosing AA. In our opinion, US should be the first-line imaging modality, as graded-compression US has excellent specificity both in the paediatric and adult patient populations. As US sensitivity is limited, and non-diagnostic US examinations with non-visualization of the appendix are more a rule than an exception, diagnostic strategies and algorithms after non-diagnostic US should focus on clinical reassessment and complementary imaging with MRI/CT if indicated. Accordingly, both ionizing radiation to our patients and cost of pre-therapeutic diagnosis of AA will be low, with low negative appendectomy and perforation rates. Main Messages • Ultrasound (US) should be the first imaging modality for diagnosing acute appendicitis (AA). • Primary US for AA diagnosis will decrease ionizing radiation and cost. • Sensitivity of US to diagnose AA is lower than of CT/MRI. • Non-visualization of the appendix should lead to clinical reassessment. • Complementary MRI or CT may be performed if diagnosis remains unclear.

Compressed sensing (CS) has been demonstrated to accelerate MRI acquisitions by reconstructing sparse images of good quality from highly undersampled data. Motion during MR scans can cause inconsistencies in k‐space data, resulting in strong motion artifacts in the reconstructed images. For CS to be useful in these applications, motion correction techniques need to be combined with the undersampled reconstruction. Recently, joint motion correction and CS approaches have been proposed to partially correct for effects of motion. However, the main limitation of these approaches is that they can only correct for affine deformations. In this work, we propose a novel motion corrected CS framework for free‐breathing dynamic cardiac MRI that incorporates a general motion correction formulation directly into the CS reconstruction. This framework can correct for arbitrary affine or nonrigid motion in the CS reconstructed cardiac images, while simultaneously benefiting from highly accelerated MR acquisition. The application of this approach is demonstrated both in simulations and in vivo data for 2D respiratory self‐gated free‐breathing cardiac CINE MRI, using a golden angle radial acquisition. Results show that this approach allows for the reconstruction of respiratory motion corrected cardiac CINE images with similar quality to breath‐held acquisitions. Magn Reson Med 70:504–516, 2013. © 2012 Wiley Periodicals, Inc.

Over the past decades, many studies have been published on the extraction of non-invasive foetal electrocardiogram (NI-FECG) from abdominal recordings. Most of these contributions claim to obtain excellent results in detecting foetal QRS (FQRS) complexes in terms of location. A small subset of authors have investigated the extraction of morphological features from the NI-FECG. However, due to the shortage of available public databases, the large variety of performance measures employed and the lack of open-source reference algorithms, most contributions cannot be meaningfully assessed. This article attempts to address these issues by presenting a standardised methodology for stress testing NI-FECG algorithms, including absolute data, as well as extraction and evaluation routines. To that end, a large database of realistic artificial signals was created, totaling 145.8 h of multichannel data and over one million FQRS complexes. An important characteristic of this dataset is the inclusion of several non-stationary events (e.g. foetal movements, uterine contractions and heart rate fluctuations) that are critical for evaluating extraction routines. To demonstrate our testing methodology, three classes of NI-FECG extraction algorithms were evaluated: blind source separation (BSS), template subtraction (TS) and adaptive methods (AM). Experiments were conducted to benchmark the performance of eight NI-FECG extraction algorithms on the artificial database focusing on: FQRS detection and morphological analysis (foetal QT and T/QRS ratio). The overall median FQRS detection accuracies (i.e. considering all non-stationary events) for the best performing methods in each group were 99.9% for BSS, 97.9% for AM and 96.0% for TS. Both FQRS detections and morphological parameters were shown to heavily depend on the extraction techniques and signal-to-noise ratio. Particularly, it is shown that their evaluation in the source domain, obtained after using a BSS technique, should be avoided. Data, extraction algorithms and evaluation routines were released as part of the fecgsyn toolbox on Physionet under an GNU GPL open-source license. This contribution provides a standard framework for benchmarking and regulatory testing of NI-FECG extraction algorithms.

OBJECTIVES: To explore the views of experts about the development and validation of a robotic surgery training curriculum, and how this should be implemented. MATERIALS AND METHODS: An international expert panel was invited to a structured session for discussion. The study was of a mixed design, including qualitative and quantitative components based on focus group interviews during the European Association of Urology (EAU) Robotic Urology Section (ERUS) (2012), EAU (2013) and ERUS (2013) meetings. After introduction to the aims, principles and current status of the curriculum development, group responses were elicited. After content analysis of recorded interviews generated themes were discussed at the second meeting, where consensus was achieved on each theme. This discussion also underwent content analysis, and was used to draft a curriculum proposal. At the third meeting, a quantitative questionnaire about this curriculum was disseminated to attendees to assess the level of agreement with the key points. RESULTS: In all, 150 min (19 pages) of the focus group discussion was transcribed (21 316 words). Themes were agreed by two raters (median agreement κ 0.89) and they included: need for a training curriculum (inter-rater agreement κ 0.85); identification of learning needs (κ 0.83); development of the curriculum contents (κ 0.81); an overview of available curricula (κ 0.79); settings for robotic surgery training ((κ 0.89); assessment and training of trainers (κ 0.92); requirements for certification and patient safety (κ 0.83); and need for a universally standardised curriculum (κ 0.78). A training curriculum was proposed based on the above discussions. CONCLUSION: This group proposes a multi-step curriculum for robotic training. Studies are in process to validate the effectiveness of the curriculum and to assess transfer of skills to the operating room.

Importance: Mechanical thrombectomy using a stent retriever or contact aspiration is widely used for treatment of patients with acute ischemic stroke due to anterior circulation large vessel occlusion, but the additional benefit of combining contact aspiration with stent retriever is uncertain. Objective: To determine whether mechanical thrombectomy for treatment of anterior circulation large vessel occlusion stroke with initial contact aspiration and stent retriever combined results in better final angiographic outcome than with standard stent retriever alone. Design, Setting, and Participants: This trial was a multicenter randomized, open-label, blinded end point evaluation that enrolled 408 patients from October 16, 2017, to May 29, 2018, in 11 French comprehensive stroke centers, with a 12-month outcome follow-up. Patients with a large vessel occlusion in the anterior circulation were included up to 8 hours after symptom onset. The final date of follow-up was June, 19, 2019. Interventions: Patients were randomly assigned (1:1 allocation) to receive initial thrombectomy with contact aspiration and stent retriever combined (205) or stent retriever alone (203). Main Outcomes and Measures: The primary outcome was the rate of expanded Thrombolysis In Cerebral Infarction score of 2c or 3 (eTICI 2c/3; ie, scores indicate near-total and total reperfusion grades) at the end of the procedure. Results: Among the 408 patients who were randomized, 3 were excluded, and 405 (99.3%) patients (mean age, 73 years; 220 [54%] women and 185 [46%] men) were included in the primary analysis. The rate of eTICI 2c/3 at the end of the endovascular procedure was not significantly different between the 2 thrombectomy groups (64.5% [131 of 203 patients] for contact aspiration and stent retriever combined vs 57.9% [117 of 202 patients] for stent retriever alone; risk difference, 6.6% [95% CI, -3.0% to 16.2%]; adjusted odds ratio [OR], 1.33 [95% CI, 0.88 to 1.99]; P = .17). Of 14 prespecified secondary efficacy end points, 12 showed no significant difference. A higher rate of successful reperfusion was achieved in the contact aspiration combined with stent retriever group vs the stent retriever alone group (eTICI 2b50/2c/3, 86.2% vs 72.3%; adjusted OR, 2.54 [95% CI, 1.51 to 4.28]; P < .001) and of near-total or total reperfusion (eTICI 2c/3, 59.6% vs 49.5%; adjusted OR, 1.52 [95% CI, 1.02 to 2.27]; P = .04) after the assigned initial intervention alone. Conclusions and Relevance: Among patients with acute ischemic stroke due to large vessel occlusion, an initial thrombectomy technique consisting of contact aspiration and stent retriever combined, compared with stent retriever alone, did not significantly improve the rate of near-total or total reperfusion (eTICI 2c/3) at the end of the endovascular procedure, although the trial may have been underpowered to detect smaller differences between groups. Trial Registration: ClinicalTrials.gov Identifier: NCT03290885.

Background and Purpose: The efficiency of prehospital care chain response and the adequacy of hospital resources are challenged amid the coronavirus disease 2019 (COVID-19) outbreak, with suspected consequences for patients with ischemic stroke eligible for mechanical thrombectomy (MT). Methods: We conducted a prospective national-level data collection of patients treated with MT, ranging 45 days across epidemic containment measures instatement, and of patients treated during the same calendar period in 2019. The primary end point was the variation of patients receiving MT during the epidemic period. Secondary end points included care delays between onset, imaging, and groin puncture. To analyze the primary end point, we used a Poisson regression model. We then analyzed the correlation between the number of MTs and the number of COVID-19 cases hospitalizations, using the Pearson correlation coefficient (compared with the null value). Results: A total of 1513 patients were included at 32 centers, in all French administrative regions. There was a 21% significant decrease (0.79; [95%CI, 0.76–0.82]; P &lt;0.001) in MT case volumes during the epidemic period, and a significant increase in delays between imaging and groin puncture, overall (mean 144.9±SD 86.8 minutes versus 126.2±70.9; P &lt;0.001 in 2019) and in transferred patients (mean 182.6±SD 82.0 minutes versus 153.25±67; P &lt;0.001). After the instatement of strict epidemic mitigation measures, there was a significant negative correlation between the number of hospitalizations for COVID and the number of MT cases ( R 2 −0.51; P =0.04). Patients treated during the COVID outbreak were less likely to receive intravenous thrombolysis and to have unwitnessed strokes (both P &lt;0.05). Conclusions: Our study showed a significant decrease in patients treated with MTs during the first stages of the COVID epidemic in France and alarming indicators of lengthened care delays. These findings prompt immediate consideration of local and regional stroke networks preparedness in the varying contexts of COVID-19 pandemic evolution.

Importance: Clinical evidence of the potential treatment benefit of mechanical thrombectomy for posterior circulation distal, medium vessel occlusion (DMVO) is sparse. Objective: To investigate the frequency as well as the clinical and safety outcomes of mechanical thrombectomy for isolated posterior circulation DMVO stroke and to compare them with the outcomes of standard medical treatment with or without intravenous thrombolysis (IVT) in daily clinical practice. Design, Setting, and Participants: This multicenter case-control study analyzed patients who were treated for primary distal occlusion of the posterior cerebral artery (PCA) of the P2 or P3 segment. These patients received mechanical thrombectomy or standard medical treatment (with or without IVT) at 1 of 23 comprehensive stroke centers in Europe, the United States, and Asia between January 1, 2010, and June 30, 2020. All patients who met the inclusion criteria were matched using 1:1 propensity score matching. Interventions: Mechanical thrombectomy or standard medical treatment with or without IVT. Main Outcomes and Measures: Clinical end point was the improvement of National Institutes of Health Stroke Scale (NIHSS) scores at discharge from baseline. Safety end point was the occurrence of symptomatic intracranial hemorrhage and hemorrhagic complications were classified based on the Second European-Australasian Acute Stroke Study (ECASSII). Functional outcome was evaluated with the modified Rankin Scale (mRS) score at 90-day follow-up. Results: Of 243 patients from all participating centers who met the inclusion criteria, 184 patients were matched. Among these patients, the median (interquartile range [IQR]) age was 74 (62-81) years and 95 (51.6%) were female individuals. Posterior circulation DMVOs were located in the P2 segment of the PCA in 149 patients (81.0%) and in the P3 segment in 35 patients (19.0%). At discharge, the mean NIHSS score decrease was -2.4 points (95% CI, -3.2 to -1.6) in the standard medical treatment cohort and -3.9 points (95% CI, -5.4 to -2.5) in the mechanical thrombectomy cohort, with a mean difference of -1.5 points (95% CI, 3.2 to -0.8; P = .06). Significant treatment effects of mechanical thrombectomy were observed in the subgroup of patients who had higher NIHSS scores on admission of 10 points or higher (mean difference, -5.6; 95% CI, -10.9 to -0.2; P = .04) and in the subgroup of patients without IVT (mean difference, -3.0; 95% CI, -5.0 to -0.9; P = .005). Symptomatic intracranial hemorrhage occurred in 4 of 92 patients (4.3%) in each treatment cohort. Conclusions and Relevance: This study suggested that, although rarely performed at comprehensive stroke centers, mechanical thrombectomy for posterior circulation DMVO is a safe, and technically feasible treatment option for occlusions of the P2 or P3 segment of the PCA compared with standard medical treatment with or without IVT.

A reconstruction strategy is proposed for physiological motion correction, which overcomes many limitations of existing techniques. The method is based on a general framework allowing correction for arbitrary motion-nonrigid or affine, making it suitable for cardiac or abdominal imaging, in the context of multiple coil, arbitrarily sampled acquisition. A model is required to predict motion in the field of view at each sample time point, based on prior knowledge provided by external sensors. A theoretical study is carried out to analyze the influence of motion prediction errors. Small errors are shown to propagate linearly in that reconstruction algorithm, and thus induce a reconstruction residue that is bounded (stability). Furthermore, optimization of the motion model is proposed in order to minimize this residue. This leads to reformulating reconstruction as two inverse problems which are coupled: motion-compensated reconstruction (known motion) and model optimization (known image). A fixed-point multiresolution scheme is described for inverting these two coupled systems. This framework is shown to allow fully autocalibrated reconstructions, as coil sensitivities and motion model coefficients are determined directly from the corrupted raw data. The theory is validated with real cardiac and abdominal data from healthy volunteers, acquired in free-breathing.