Publications by authors named "Konovalov A"

Unlabelled: Augmented reality (AR) is a promising area in microsurgical treatment of cerebrovascular pathologies that can significantly facilitate preoperative planning and intraoperative understanding of anatomy.

Objective: To describe AR-assisted neuronavigation in microsurgical treatment of intracranial aneurysms, arteriovenous malformations and cavernomas; to evaluate accuracy and applicability of AR-assisted neuronavigation.

Material And Methods: The study involved 22 patients with cerebral aneurysms, arteriovenous and cavernous malformations.

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Unlabelled: Craniopharyngioma is a benign tumor in adults and children characterized by local invasion of surrounding brain structures. HARDI-CSD tractography is one of the modern MR methods for comprehensive visualization of functionally significant conduction pathways.

Objective: To determine the possibility of visualizing some structures of chiasmatic-sellar region and third ventricle (hypothalamic-pituitary tract (pituitary stalk), optic pathways, fornix, mammillothalamic tract) using HARDI-CSD tractography in patients with suprasellar craniopharyngiomas, especially after failed CT and standard MRI of these structures.

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Unlabelled: Despite the progress in understanding the pathogenesis of diffuse brainstem tumors, treatment of these neoplasms is usually empirical and conducted without morphological and molecular verification. Liquid biopsy is a minimally invasive technique providing data on tumor biology without standard biopsy. This method is based on analysis of cell-free nucleic acids (predominantly, extracellular DNA) in biological fluids with detection of specific mutations.

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Current study presents an advanced method for improving the visualization of subsurface blood vessels using laser speckle contrast imaging (LSCI), enhanced through principal component analysis (PCA) filtering. By combining LSCI and laser speckle entropy imaging with PCA filtering, the method effectively separates static and dynamic components of the speckle signal, significantly improving the accuracy of blood flow assessments, even in the presence of static scattering layers located above and below the vessel. Experiments conducted on optical phantoms, with the vessel depths ranging from 0.

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Unlabelled: Tumor tissue samples are necessary for histological diagnosis. Biopsy is associated with certain difficulties, especially in neuro-oncology. An alternative approach (liquid biopsy) is currently being developed.

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It is well known that the number of true truffles in the wild is decreasing. The aim of the study was to develop an effective, simple and affordable method of asci disruption to release black truffle spores. It was shown that the spore release can be achieved by different ways, such as mechanical or biological destruction.

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Article Synopsis
  • Craniopharyngiomas (CP) are benign tumors located near key brain structures, and their surgical removal depends on their specific anatomical positioning.
  • A literature review identified 21 studies analyzing the topographic and anatomical classifications of CP, focusing on relationships to critical areas like the hypothalamic-pituitary axis and third ventricle.
  • Understanding these classifications is essential for determining the appropriate surgical methods and improving diagnostic techniques, particularly through advanced imaging like high-resolution MRI.
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Article Synopsis
  • Craniopharyngioma (CP) is a benign tumor located mainly in the brain's chiasmatic-sellar region, with two main types: adamantinoma-like (ACP) and papillomatous (PCP), the latter mostly affecting adults.
  • The study aimed to determine the disease-free survival in adults with newly diagnosed CP based on the quality of tumor removal and the effectiveness of irradiation, using data from 398 patients over a decade.
  • Results showed that total tumor resection significantly lowers recurrence risk, while stereotactic irradiation after incomplete resection also yields favorable outcomes, with PCPs being less aggressive and less likely to recur after complete removal.
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Pollution by active ingredients is one of the most significant and widespread forms of pollution on Earth. Medicines can have a negative impact on ecosystems, and contamination can have unpredictable consequences. An urgent and unexplored task is to study the Lake Baikal ecosystem and its organisms for the presence of trace concentrations of active pharmaceutical ingredients.

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Mesoporous hydroxyapatite (HA) is widely used in various applications, such as the biomedical field, as a catalytic, as a sensor, and many others. The aim of this work was to obtain HA powders by means of chemical precipitation in a medium containing a polymer-polyvinyl alcohol or polyvinylpyrrolidone (PVP)-with concentrations ranging from 0 to 10%. The HA powders were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic emission spectroscopy with inductively coupled plasma, electron paramagnetic resonance, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

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Background: Optimization of the dose the patient receives during scanning is an important problem in modern medical X-ray computed tomography (CT). One of the basic ways to its solution is to reduce the number of views. Compressed sensing theory helped promote the development of a new class of effective reconstruction algorithms for limited data CT.

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Currently, there is a unanimous opinion that the first line of the treatment of insular gliomas is microsurgical removal. At the same time, surgery of insular glial tumors remains a challenge because of the complex anatomy of the insular region. Among the most crucial anatomical structures are branches of the middle cerebral artery (MCA), lenticulostriate arteries (LSAs), and corticospinal tract.

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Background: Patients with intracranial aneurysms often have comorbidities that require them to take acetylsalicylic acid (ASA). In recent years, many patients with aneurysms have been prescribed ASA to prevent aneurysm enlargement. ASA is also prescribed to patients with intracranial aneurysms in preparation for surgical revascularization.

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Humans are known to be capable of inferring hidden preferences and beliefs of their conspecifics when observing their decisions. While observational learning based on choices has been explored extensively, the question of how response times (RT) impact our learning of others' social preferences has received little attention. Yet, while observing choices alone can inform us about the direction of preference, they reveal little about the strength of this preference.

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Background: Treatment of patients with prolonged and permanent disturbance of consciousness is still an extremely difficult problem. Nowadays, management is based on pathophysiological and molecular mechanisms of impaired consciousness. Several electrophysiological and pharmacological methods were proposed to restore consciousness in appropriate patients.

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Background: Contrast enhancement of intracranial aneurysm wall during MRI with targeted visualization of vascular wall correlates with previous aneurysm rupture and, according to some data, may be a predictor of further rupture of unruptured aneurysms.

Objective: To analyze possible causes of aneurysm contrast enhancement considering morphological data of aneurysm walls.

Material And Methods: The study included 44 patients with intracranial aneurysms who underwent preoperative MRI between November 2020 and September 2022.

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Unlabelled: Microsurgeries are common for complex aneurysms of the middle cerebral artery (MCA).

Objective: To evaluate the incidence and types of venous cerebral disorders after microsurgeries for complex MCA aneurysms.

Material And Methods: A retrospective study included 285 patients with complex MCA aneurysms between 2009 and 2020.

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Modern neuroimaging methods do not completely rule out false diagnoses of intracranial aneurysms which can lead to an unwarranted operation associated with risks of complications. However, surgical interventions for falsely diagnosed aneurysms are quite rare. The purpose of this study is to demonstrate two clinical cases of false-positive aneurysms and a systematic review of the literature dedicated to the incidence and etiology of false-positive aneurysms, identifying risk factors associated with false-positive aneurysms.

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Aspirin is widely used for primary or secondary prevention of ischemic events. At the same time, chronic aspirin consumption can affect blood clot formation during surgical intervention and increase intraoperative blood loss This is especially important for high-risk surgery, including neurosurgery. Current European Society of Cardiology guidelines recommend aspirin interruption for at least 7 d before neurosurgical intervention, but this suggestion is not supported by clinical evidence.

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Primary brainstem gliomas are still poorly studied in neurooncology. This concept includes tumors with different histological and genetic features, as well as variable clinical course and outcomes. Nevertheless, treatment implies radiotherapy without a clear idea of morphological substrate of disease in 80% of cases.

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Objective: To evaluate mechanical strength of three methods of polymethyl methacrylate skull implant fixation in two experimental models.

Material And Methods: The first experiment was performed on a plastic model that was as close as possible to bone in structural characteristics. The second experiment was performed on a biological specimen (a ram's head).

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Purpose: To report our experience with patient specific implants for one-step orbit reconstruction following hyperostotic SWM removal and to describe the evolution of the technique through three surgical cases. Methods: Three cases of one-step SWM removal and orbit reconstruction are described. All cases are given consecutively to describe the evolution of the technique.

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The use of various blood flow control methods in neurovascular interventions is crucial for reducing postoperative complications. Neurosurgeons worldwide use different methods, such as contact Dopplerography, intraoperative indocyanine videoangiography (ICG) video angiography, fluorescein angiography, flowmetry, intraoperative angiography, and direct angiography. However, there is no noninvasive method that can assess the presence of blood flow in the vessels of the brain without the introduction of fluorescent substances throughout the intervention.

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Using an 185-kg NaI[Tl] array, COHERENT has measured the inclusive electron-neutrino charged-current cross section on ^{127}I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source at Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤50  MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of 9.

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Background: Chordoid glioma is a rare slow-growing tumor of the central nervous system. Available world experience includes no more than 200 cases (lesion of the third ventricle in absolute majority of cases). Recognition and treatment of chordoid glioma are currently difficult problems due to small incidence of this disease.

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