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  • 1
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    4D-CT angiography versus 3D-rotational angiography as the imaging modality for computational fluid dynamics of cerebral aneurysms
    BMJ ; 2020
    In:  Journal of NeuroInterventional Surgery Vol. 12, No. 6 ( 2020-06), p. 626-630
    Details
    In: Journal of NeuroInterventional Surgery, BMJ, Vol. 12, No. 6 ( 2020-06), p. 626-630
    Abstract: Computational fluid dynamics (CFD) can provide valuable information regarding intracranial hemodynamics. Patient-specific models can be segmented from various imaging modalities, which may influence the geometric output and thus hemodynamic results. This study aims to compare CFD results from aneurysm models segmented from three-dimensional rotational angiography (3D-RA) versus novel four-dimensional CT angiography (4D-CTA). Methods Fourteen patients with 16 cerebral aneurysms underwent novel 4D-CTA followed by 3D-RA. Endoluminal geometries were segmented from each modality using an identical workflow, blinded to the other modality, to produce 28 'original' models. Each was then minimally edited a second time to match length of branches, producing 28 additional 'matched' models. CFD simulations were performed using estimated flow rates for 'original' models (representing real-world experience) and patient-specific flow rates from 4D-CTA for 'matched' models (to control for influence of modality alone). Results Overall, geometric and hemodynamic results were consistent between models segmented from 3D-RA and 4D-CTA, with correlations improving after matching to control for operator-introduced variability. Despite smaller 4D-CTA parent artery diameters (3.49±0.97 mm vs 3.78±0.92 mm for 3D-RA; p=0.005) and sac volumes (157 (37–750 mm 3 ) vs 173 (53–770 mm 3 ) for 3D-RA; p=0.0002), sac averages of time-averaged wall shear stress (TAWSS), oscillatory shear (OSI), and high frequency fluctuations (measured by spectral power index, SPI) were well correlated between 3D-RA and 4D-CTA 'matched' control models (TAWSS, R 2 =0.91; OSI, R 2 =0.79; SPI, R 2 =0.90). Conclusions Our study shows that CFD performed using 4D-CTA models produces reliable geometric and hemodynamic information in the intracranial circulation. 4D-CTA may be considered as a follow-up imaging tool for hemodynamic assessment of cerebral aneurysms.
    Type of Medium: Online Resource
    ISSN: 1759-8478 , 1759-8486
    URL: Article
    DOI: 10.1136/neurintsurg-2019-015389
    Language: English
    Publisher: BMJ
    Publication Date: 2020
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  • 2
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    Robotic-assisted intracranial aneurysm treatment: 1 year follow-up imaging and clinical outcomes
    BMJ ; 2022
    In:  Journal of NeuroInterventional Surgery Vol. 14, No. 12 ( 2022-12), p. 1229-1233
    Details
    In: Journal of NeuroInterventional Surgery, BMJ, Vol. 14, No. 12 ( 2022-12), p. 1229-1233
    Abstract: The use of robotics in medicine may enable increased technical accuracy, reduced procedural time and radiation exposure, and remote completion of procedures. We have previously described the first-in-human, robotic-assisted cerebral aneurysm treatment using the CorPath GRX Robotic System. In this report we discuss our early experiences and outcomes using this robotic device for endovascular treatment of intracranial aneurysms using stent-assisted coil embolization and flow diversion. Methods The patient and disease characteristics, procedural details, and follow-up imaging and clinical outcomes of consecutive patients undergoing robotically-assisted intracranial aneurysm embolization between November 2019 and February 2020 are presented. Results Six patients underwent robotically-assisted embolization of intracranial aneurysms. Four of the patients were treated with a neck-bridging stent (with or without coiling) and two patients were treated with a flow-diverting stent. Two patients were treated in the subacute period of subarachnoid hemorrhage and four patients were treated electively. All of the procedures could be completed robotically and there was no need for unplanned manual intervention. The technical success rate of the procedures was 100%. There was no morbidity or mortality associated with the procedures. One year follow-up imaging showed that four aneurysms were completely obliterated (Raymond-Roy Occlusion Classification (RROC) class I) and the remaining two were occluded with a residual neck (RROC class II). Conclusions The Corpath GRX Robotic System demonstrated a precise control over the microcatheter, wire and stent during aneurysm treatment. Robotic neuro-procedures seem to be safe and effective and demonstrate stable occlusion results in the midterm follow-up.
    Type of Medium: Online Resource
    ISSN: 1759-8478 , 1759-8486
    URL: Article
    DOI: 10.1136/neurintsurg-2021-017865
    Language: English
    Publisher: BMJ
    Publication Date: 2022
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  • 3
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    Torrents of torment: turbulence as a mechanism of pulsatile tinnitus secondary to venous stenosis revealed by high-fidelity computational fluid dynamics
    BMJ ; 2021
    In:  Journal of NeuroInterventional Surgery Vol. 13, No. 8 ( 2021-08), p. 732-737
    Details
    In: Journal of NeuroInterventional Surgery, BMJ, Vol. 13, No. 8 ( 2021-08), p. 732-737
    Abstract: Pulsatile tinnitus (PT) is a debilitating condition that can be caused by a vascular abnormality, such as an arterial or venous lesion. Although treatment of PT-related venous lesions has been shown to successfully cure patients of the associated ‘tormenting’ rhythmical sound, much controversy still exists regarding their role in the etiology of PT. Methods A patient presented with a history of worsening, unilateral PT. A partial venous sinus obstruction related to the large arachnoid granulation was detected on the right side, and subsequently stented at the right transverse sinus. High-fidelity computational fluid dynamics (CFD) was performed on a 3D model digitally segmented from the pre-stent venogram, with assumed pulsatile flow rates. A post-stent CFD model was also constructed from this. Data-driven sonification was performed on the CFD velocity data, blinded to the patient’s self-reported sounds. Results The patient reported that the PT was completely resolved after stenting, and has had no recurrence of the symptoms after more than 2 years. CFD simulation revealed highly disturbed, turbulent-like flow at the sigmoid sinus close to auditory structures, producing a sonified audio signal that reproduced the subjective sonance of the patient’s PT. No turbulence or sounds were evident at the stenosis, or anywhere in the post-stent model. Conclusions For the first time, turbulence generated distal to a venous stenosis is shown to be a cause of PT. High-fidelity CFD may be useful for identifying patients with such ‘torrents’ of flow, to help guide treatment decision-making.
    Type of Medium: Online Resource
    ISSN: 1759-8478 , 1759-8486
    URL: Article
    DOI: 10.1136/neurintsurg-2020-016636
    Language: English
    Publisher: BMJ
    Publication Date: 2021
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  • 4
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    Biomodex patient-specific brain aneurysm models: the value of simulation for first in-human experiences using new devices and robotics
    BMJ ; 2021
    In:  Journal of NeuroInterventional Surgery Vol. 13, No. 3 ( 2021-03), p. 272-277
    Details
    In: Journal of NeuroInterventional Surgery, BMJ, Vol. 13, No. 3 ( 2021-03), p. 272-277
    Abstract: With the recent advent of advanced technologies in the field, treatment of neurovascular diseases using endovascular techniques is rapidly evolving. Here we describe our experience with pre-surgical simulation using the Biomodex EVIAS patient-specific 3D-printed models to plan aneurysm treatment using endovascular robotics and novel flow diverter devices. Methods Pre-procedural rehearsals with 3D-printed patient-specific models of eight cases harboring brain aneurysms were performed before the first in-human experiences. To assess the reliability of the experimental model, the characteristics of the aneurysms were compared between the patient and 3D models. The rehearsals were used to define the patient treatment plan, including technique, device sizing, and operative working projections. Results The study included eight patients with their respective EVIAS 3D aneurysm models. Pre-operative simulation was performed for the first in-human robotic-assisted neurovascular interventions (n=2) and new generation flow-diverter stents (n=6). Aneurysms were located in both the anterior (n=5) and posterior (n=3) circulation and were on average 11.0±6.5 mm in size. We found reliable reproduction of the aneurysm features and similar dimensions of the parent vessel anatomy between the 3D models and patient anatomy. Information learned from pre-surgical in vitro simulation are described in detail, including an improved patient treatment plan, which contributed to successful first in-world procedures with no intraprocedural complications. Conclusions Pre-procedural rehearsal using patient-specific 3D models provides precise procedure planning, which can potentially lead to greater operator confidence, decreased radiation dose and improvements in patient safety, particularly in first in-human experiences.
    Type of Medium: Online Resource
    ISSN: 1759-8478 , 1759-8486
    URL: Article
    DOI: 10.1136/neurintsurg-2020-015990
    Language: English
    Publisher: BMJ
    Publication Date: 2021
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  • 5
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    Feasibility of robot-assisted neuroendovascular procedures
    Journal of Neurosurgery Publishing Group (JNSPG) ; 2022
    In:  Journal of Neurosurgery Vol. 136, No. 4 ( 2022-04-01), p. 992-1004
    Details
    In: Journal of Neurosurgery, Journal of Neurosurgery Publishing Group (JNSPG), Vol. 136, No. 4 ( 2022-04-01), p. 992-1004
    Abstract: Geographic factors prevent equitable access to urgent advanced neuroendovascular treatments. Robotic technologies may enable remote endovascular procedures in the future. The authors performed a translational, benchtop-to-clinical study to evaluate the in vitro and clinical feasibility of the CorPath GRX Robotic System for robot-assisted endovascular neurointerventional procedures. METHODS A series of bench studies was conducted using patient-specific 3D-printed models to test the system’s compatibility with standard neurointerventional devices, including microcatheters, microwires, coils, intrasaccular devices, and stents. Optimal baseline setups for various procedures were determined. The models were further used to rehearse clinical cases. Subsequent to these investigations, a prospective series of 6 patients was treated using robotic assistance for complex, wide-necked intracranial saccular aneurysms between November 2019 and February 2020. The technical success, incidence of periprocedural complications, and need for conversion to manual procedures were evaluated. RESULTS The ideal robotic setup for treatment of both anterior and posterior circulation aneurysms was determined to consist of an 80-cm guide catheter with a 115-cm-long intermediate catheter, a microcatheter between 150 and 170 cm in length, and a microwire with a minimum length of 300 cm. All coils, intrasaccular devices, and stents tested were compatible with the system and could be advanced or retracted safely and placed accurately. All 6 clinical procedures were technically successful, with all intracranial steps being performed robotically with no conversions to manual intervention or failures of the robotic system. There were no procedure-related complications or adverse clinical outcomes. CONCLUSIONS This study demonstrates the feasibility of robot-assisted neurointerventional procedures. The authors’ results represent an important step toward enabling remote neuroendovascular care and geographic equalization of advanced endovascular treatments through so-called telestroke intervention.
    Type of Medium: Online Resource
    ISSN: 0022-3085 , 1933-0693
    URL: Article
    DOI: 10.3171/2021.1.JNS203617
    RVK:
    XA 10000
    RVK:
    XA 55270
    Language: Unknown
    Publisher: Journal of Neurosurgery Publishing Group (JNSPG)
    Publication Date: 2022
    detail.hit.zdb_id: 2026156-1
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  • 6
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    Novel flat-panel cone-beam CT compared to multi-detector CT for assessment of acute ischemic stroke: A prospective study
    Elsevier BV ; 2021
    In:  European Journal of Radiology Vol. 138 ( 2021-05), p. 109645-
    Details
    In: European Journal of Radiology, Elsevier BV, Vol. 138 ( 2021-05), p. 109645-
    Type of Medium: Online Resource
    ISSN: 0720-048X
    URL: Article
    DOI: 10.1016/j.ejrad.2021.109645
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
    detail.hit.zdb_id: 2005350-2
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  • 7
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    Abstract 141: Artificial Intelligence to Improve the Detection and Triage of Cerebral Aneurysms
    Ovid Technologies (Wolters Kluwer Health) ; 2020
    In:  Stroke Vol. 51, No. Suppl_1 ( 2020-02)
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 51, No. Suppl_1 ( 2020-02)
    Abstract: Cerebral Aneurysms (CAs) may occur in 5-10% of the population. They can be often missed because they require a very methodological diagnostic approach. We developed an algorithm using artificial intelligence to assist and supervise and detect CAs. Methods: We developed an automated algorithm to detect CAs. The algorithm is based on 3D convolutional neural network modeled as a U-net. We included all saccular CAs from 2014 to 2016 from a single center. Normal and pathological datasets were prepared and annotated in 3D using an in-house developed platform. To assess the accuracy and to optimize the model, we assessed preliminary results using a validation dataset. After the algorithm was trained, a dataset was used to evaluate final IA detection and aneurysm measurements. The accuracy of the algorithm was derived using ROC curves and Pearson correlation tests. Results: We used 528 CTAs with 674 aneurysms at the following locations: ACA (3%), ACA/ACOM (26.1%), ICA/MCA (26.3%), MCA (29.4%), PCA/PCOM (2.3%), Basilar (6.6%), Vertebral (2.3%) and other (3.7%). Training datasets consisted of 189 CA scans. We plotted ROC curves and achieved an AUC of 0.85 for unruptured and 0.88 for ruptured CAs. We improved the model performance by increasing the training dataset employing various methods of data augmentation to leverage the data to its fullest. The final model tested was performed in 528 CTAs using 5-fold cross-validation and an additional set of 2400 normal CTAs. There was a significant improvement compared to the initial assessment, with an AUC of 0.93 for unruptured and 0.94 for ruptured. The algorithm detected larger aneurysms more accurately, reaching an AUC of 0.97 and a 91.5% specificity at 90% sensitivity for aneurysms larger than 7mm. Also, the algorithm accurately detected CAs in the following locations: basilar(AUC of 0.97) and MCA/ACOM (AUC of 0.94). The volume measurement (mm3) by the model compared to the annotated one achieved a Pearson correlation of 99.36. Conclusion: The Viz.ai aneurysm algorithm was able to detect and measure ruptured and unruptured CAs in consecutive CTAs. The model has demonstrated that a deep learning AI algorithm can achieve clinically useful levels of accuracy for clinical decision support.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.51.suppl_1.141
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2020
    detail.hit.zdb_id: 1467823-8
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  • 8
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    Robust cerebrovascular blood velocity and flow rate estimation from 4D‐ CTA
    Wiley ; 2019
    In:  Medical Physics Vol. 46, No. 5 ( 2019-05), p. 2126-2136
    Details
    In: Medical Physics, Wiley, Vol. 46, No. 5 ( 2019-05), p. 2126-2136
    Abstract: Blood velocity and flow rate information may be helpful for a wide variety of applications, but it often requires separate acquisitions. The dynamic information combined with the high spatial resolution of four‐dimensional computed tomography angiography (4D‐CTA) offers the possibility to quantify blood flow simultaneous to vascular anatomy. Methods A 4D‐ CTA clinical protocol with a novel dedicated postprocessing were validated in vitro in a patient‐specific model, and tested in a pilot study of six patients. Blood flow was assessed in both internal carotid ( ICA s) and vertebral ( VA s) arteries by analyzing spatial displacement of contrast agent in the form of time‐intensity curves ( TIC s). Unlike previous approaches, it does not require any a priori assumptions about TIC shape, but rather computes mean velocity and flow rates from the spatial displacement of the TIC s along the automatically segmented vessels. Results In vitro experiments showed good agreement between 4D‐ CTA and flowmeter measurements under steady and pulsatile flow conditions. In vivo measurements exhibited large interpatient variability of the TIC shapes, from which blood flow rates could nevertheless be successfully measured in all patients and investigated vessels. On average, measured flow rates were 3.2 ± 0.7 ml/s (in ICA s) and 1.3 ± 0.8 ml/s (in VA s) consistent with previous reference standards. Contrary to our novel approach, which considered the full TIC shape, application of previous time‐to‐peak analyses based on idealized TIC shapes showed limited reliability. Conclusions We demonstrate the high potential of 4D‐ CTA for assessing blood velocity and flow rate in addition to anatomical evaluation. The wide variety of TIC shapes encountered in vivo highlights the importance of an adaptive TIC analysis as proposed in the present work.
    Type of Medium: Online Resource
    ISSN: 0094-2405 , 2473-4209
    URL: Issue
    URL: Article
    DOI: 10.1002/mp.2019.46.issue-5
    DOI: 10.1002/mp.13454
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1466421-5
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  • 9
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    First-in-human, robotic-assisted neuroendovascular intervention
    BMJ ; 2020
    In:  Journal of NeuroInterventional Surgery Vol. 12, No. 4 ( 2020-04), p. 338-340
    Details
    In: Journal of NeuroInterventional Surgery, BMJ, Vol. 12, No. 4 ( 2020-04), p. 338-340
    Abstract: Robotic-assisted technology has been used as a tool to enhance open and minimally invasive surgeries as well as percutaneous coronary and peripheral vascular interventions. It offers many potential benefits, including increased procedural and technical accuracy as well as reduced radiation dose during fluoroscopic procedures. It also offers the potential for truly “remote” procedures. Despite these benefits, robotic technology has not yet been used in the neuroendovascular field, aside from diagnostic cerebral angiography. Here, we report the first robotic-assisted, therapeutic, neuroendovascular intervention performed in a human. This was a stent-assisted coiling procedure to treat a large basilar aneurysm. All intracranial steps, including stent placement and coil deployment, were performed with assistance from the CorPath 〈 sup 〉 © 〈 /sup 〉 GRX Robotic System (Corindus, a Siemens Healthineers Company, Waltham, MA, USA). This represents a major milestone in the treatment of neurovascular disease and opens the doors for the development of remote robotic neuroendovascular procedures.
    Type of Medium: Online Resource
    ISSN: 1759-8478 , 1759-8486
    URL: Article
    DOI: 10.1136/neurintsurg-2019-015671.rep
    Language: English
    Publisher: BMJ
    Publication Date: 2020
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  • 10
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    Comparison of intra-aneurysmal flow modification using optical flow imaging to evaluate the performance of Evolve and Pipeline flow diverting stents
    BMJ ; 2020
    In:  Journal of NeuroInterventional Surgery Vol. 12, No. 8 ( 2020-08), p. 814-817
    Details
    In: Journal of NeuroInterventional Surgery, BMJ, Vol. 12, No. 8 ( 2020-08), p. 814-817
    Abstract: Flow diverting stent (FDS) devices have revolutionized the treatment of large and complex brain aneurysms, but there is still room for improvement, particularly on the flow diversion properties and technical challenges associated with stent deployment. In this study we compared flow diversion properties between the new generation Surpass Evolve (Stryker) and the Pipeline Flex (Medtronic) devices by quantitatively evaluating intra-aneurysmal flow modification. Methods An in vitro experimental set-up was used, consisting of four patient-specific silicone models with internal carotid aneurysms and a circulating hemodynamic simulation system with pulsatile flow. The Evolve and Pipeline stents were deployed across the neck of each aneurysm model, in a randomized fashion, for a total of eight device deployments. A 60 frames/s digital subtraction angiography run was acquired before and after placement of each FDS. An optical flow-analysis method was used to measure intra-aneurysmal flow modification induced by the stent by calculating a mean aneurysm flow amplitude (MAFA) before and after stent placement and computing a ratio. Results Average MAFA ratio values calculated from pre- and post-stent placement were significantly lower after deployment of the Evolve (n=4, mean=0.62±0.09) compared with the Pipeline device (n=4, mean=0.71±0.06) (p=0.03). Conclusions Our in vitro results show that the Evolve stent had a superior flow diversion effect compared with the Pipeline stent, which—based on clinical evidence—suggest it may promote faster aneurysm occlusion rates in patients.
    Type of Medium: Online Resource
    ISSN: 1759-8478 , 1759-8486
    URL: Article
    DOI: 10.1136/neurintsurg-2019-015696
    Language: English
    Publisher: BMJ
    Publication Date: 2020
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