Publications by authors named "Gounis M"

Objective: Image-guided diagnosis and treatment of lung lesions is an active area of research. With the growing number of solutions proposed, there is also a growing need to establish a standard for the evaluation of these solutions. Thus, realistic phantom and preclinical environments must be established.

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  • Current localized intravascular treatments usually involve solid implants or therapeutic injections, which can spread beyond the target area.* -
  • This new technique uses fluids and their surface tension to specifically target and treat brain aneurysms by positioning a separate fluid phase at the aneurysm's neck.* -
  • The method has been validated through computer simulations and experiments, showing successful localized delivery and treatment without affecting surrounding areas, making it a promising option for cardiovascular treatments.*
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Neurological disorders pose a challenge for targeted therapy due to restricted access of therapeutic agents to the central nervous system (CNS). Current methods are limited by procedure-related risks, invasiveness, and insufficient CNS biodistribution. A novel percutaneous transvenous technology, currently in clinical trials for communicating hydrocephalus, offers a minimally invasive approach by providing endovascular access to the cerebrospinal fluid-filled cerebellopontine angle (CPA) cistern.

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Neurofibromatosis type 1 (NF1) is a human genetic disorder caused by variants in the NF1 gene. Plexiform neurofibromas, one of many NF1 manifestations, are benign peripheral nerve sheath tumors occurring in up to 50% of NF1 patients. A substantial fraction of NF1 pathogenetic variants are nonsense mutations, which result in the synthesis of truncated non-functional NF1 protein (neurofibromin).

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  • * In a controlled experiment, ten dogs underwent a procedure to block blood flow to the brain temporarily and were divided into two groups: one receiving selective brain cooling and the other receiving no treatment.
  • * Results indicated that while overall survival rates were similar, the cooled group experienced significantly slower progression of brain tissue damage after blood flow restoration compared to the control group.
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X-ray attenuating contrast agents for imaging thrombi directly during endovascular thrombectomy (EVT) are urgently needed for shortening the wait time for treatment and for reducing the chances of blood clot fragmentation. Neutrophil extracellular traps (NETs) are a product of an innate immune system response by which neutrophils release decondensed chromatin strands decorated with granule and cytosolic proteins, including neutrophil elastase and citrullinated histone H3 (CitH3). NETs are frequently found within fibrous thrombi in pathology and represent a promising target for thrombi-specific imaging agents due to their common occurrence in human cerebrovascular thrombi.

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Background: Multiple studies and meta-analyses have described the technical and clinical outcomes in large cohorts of aneurysm patients treated with flow diverters (FDs). Variations in evaluation methodology complicate making comparisons among studies, hinder understanding of the device behavior, and pose an obstacle in the assessment of further advances in FD therapy.

Methods: A multidisciplinary panel of neurointerventionalists, imaging experts, and neuroradiologists convened with the goal of establishing consensus recommendations for the standardization of image analyses in FD studies.

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Endovascular interventions are increasingly becoming the preferred approach for treating strokes and cerebral artery diseases. These procedures rely on sophisticated angiographical imaging guidance, which encounters challenges because of limited contrast and spatial resolution. Achieving a more precise visualization of the underlying arterial pathology and neurovascular implants is crucial for accurate procedural decision-making.

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  • Brain aneurysms (IAs) are dangerous and can cause serious health problems, but doctors have many ways to treat them, and there’s still debate about the best method.!
  • A group of experts met to discuss new research, treatment options, and the use of technology like artificial intelligence to better manage brain aneurysms and predict their risks.!
  • The experts agreed that collecting more data and using advanced imaging techniques could help improve patient care, especially in big hospitals with the right specialists.!
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Background: Middle meningeal artery (MMA) embolization is a promising intervention as a stand-alone or adjunct treatment to surgery in patients with chronic subdural hematomas. There are currently no large animal models for selective access and embolization of the MMA for preclinical evaluation of this endovascular modality. Our objective was to introduce a novel in vivo model of selective MMA embolization in swine.

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Background: The aim of this study was to evaluate the overall rates of braid changes associated with flow diverter (FD) treatment for intracranial aneurysms (IAs). Additionally, we sought to provide an overview of the currently reported definitions related to these complications.

Methods: A systematic search was conducted from the inception of relevant literature up to April 2023, encompassing six databases.

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Oligonucleotide therapeutics offer great promise in the treatment of previously untreatable neurodegenerative disorders; however, there are some challenges to overcome in pre-clinical studies. (1) They carry a well-established dose-related acute neurotoxicity at the time of administration. (2) Repeated administration into the cerebrospinal fluid may be required for long-term therapeutic effect.

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Flow-diverting stents (FDs) for the treatment of cerebrovascular aneurysms are revolutionary. However, these devices require systemic dual antiplatelet therapy (DAPT) to reduce thromboembolic complications. Given the risk of ischemic complications as well as morbidity and contraindications associated with DAPT, demonstrating safety and efficacy for FDs either without DAPT or reducing the duration of DAPT is a priority.

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  • * Outcomes showed that 80% of aneurysms treated with SEAL Arc achieved complete occlusion, significantly higher than the 21% for WEB, alongside better neointimal coverage (86% vs. 49%).
  • * Histological results indicated that all aneurysms treated with SEAL Arc were completely healed, suggesting the device is a promising option for early aneurysm treatment.
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Background: Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes.

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  • Flow diversion is a common treatment for cerebral aneurysms but has notable downsides, including the need for dual antiplatelet therapy and slow healing of the aneurysm.
  • New surface modifications like the phosphorylcholine polymer aim to reduce blood clot risk, but concerns exist about potential delays in healing.
  • A study using different flow diverters in rabbits found no significant differences in tissue growth or healing between devices, indicating that the Shield modification does not negatively affect the integration process.
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Background: Flow diverters carry the risk of thromboembolic complications (TEC). We tested a coating with covalently bound heparin that activates antithrombin to address TEC by locally downregulating the coagulation cascade. We hypothesized that the neuroimaging evidence of TEC would be reduced by the coating.

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  • Predicting difficult clots during mechanical thrombectomy for acute stroke is challenging due to unclear definitions of what constitutes a "challenging clot."
  • Experts participated in a modified DELPHI technique survey to identify specific features of these clots, reaching consensus on several defining characteristics.
  • Eight key features that indicate a challenging clot include its color, stiffness, adherence, and resistance, highlighting the need for further research to improve identification before treatment.
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Background: Diagnosing and treating acute ischemic stroke patients within a narrow timeframe is challenging. Time needed to access the occluded vessel and initiate thrombectomy is dictated by the availability of information regarding vascular anatomy and trajectory. Absence of such information potentially impacts device selection, procedure success, and stroke outcomes.

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Background: Infarct volume measured from 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain slices is critical to stroke models. In this study, we developed an interactive, tunable, software that automatically computes whole-brain infarct metrics from serial TTC-stained brain sections.

Methods: Three rat ischemic stroke cohorts were used in this study (Total  = 91 rats; Cohort 1  = 21, Cohort 2  = 40, Cohort 3  = 30).

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(1) Background: Intracranial pressure (ICP) monitoring plays a key role in the treatment of patients in intensive care units, as well as during long-term surgeries and interventions. The gold standard is invasive measurement and monitoring via ventricular drainage or a parenchymal probe. In recent decades, numerous methods for non-invasive measurement have been evaluated but none have become established in routine clinical practice.

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Background: The first-pass complete recanalization by mechanical thrombectomy (MT) for the treatment of stroke remains limited due to the poor integration of the clot within current devices. Aspiration can help retrieval of the main clot but fails to prevent secondary embolism in the distal arterial territory. The dense meshes of extracellular DNA, recently described in stroke-related clots, might serve as an anchoring platform for MT devices.

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Background: Neurointerventionalists use in-vitro vascular models to train for worst-case scenarios and test new devices in a simulated use environment to predict clinical performance. According to the Food and Drug Administration (FDA), any neurovascular navigation device should be able to successfully navigate two 360-degree turns and two 180-degree turns at the distal portion of the anatomical model. Here, we present a device benchmarking vascular model that complies with FDA recommendations.

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Objectives: Inflammation plays a key role in driving brain aneurysmal instability and rupture, but clinical tools to noninvasively differentiate between inflamed and stable aneurysms are lacking. We hypothesize that imaging oxidative changes in the aneurysmal microenvironment driven by myeloid inflammatory cells may represent a noninvasive biomarker to evaluate rupture risk. In this study, we performed initial evaluation of the oxidatively activated probe Fe-PyC3A as a tool for magnetic resonance imaging (MRI) of inflammation in a rabbit model of saccular aneurysm.

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