[MR-guided non-invasive typing of brain gliomas using machine learning]. / Pervye rezul'taty neinvazivnogo tipirovaniya gliom golovnogo mozga po dannym magnitno-rezonansnoi tomografii s pomoshch'yu mashinnogo obucheniya.

Gliomas are the most common neuroepithelial brain tumors. The modern classification of tumors of central nervous system and treatment approaches are based on tissue and molecular features of a particular neoplasm. Today, histological and molecular genetic typing of tumors can only be carried out through invasive procedures. In this regard, non-invasive preoperative diagnosis in neurooncology is appreclated. One of the perspective areas is artificial intelligence applied for neuroimaging to identify significant patterns associated with histological and molecular profiles of tumors and not obvlous for a specialist. OBJECTIVE: To evaluate diagnostic accuracy of deep learning methods for glioma typing according to the 2007 WHO classification based on preoperative magnetic resonance imaging (MRI) data. MATERIAL AND METHODS: The study included MR scans of patients with glial tumors undergoing neurosurgical treatment at the Burdenko National Medical Research Center for Neurosurgery. All patients underwent preoperative contrast-enhanced MRI. 2D and 3D MR scans were used for learning of artificial neural networks with two architectures (Resnest200e and DenseNet, respectively) in classifying tumors into 4 categories (WHO grades I-IV). Learning was provided on 80% of random examinations. Classification quality metrics were evaluated in other 20% of examinations (validation and test samples). RESULTS: Analysis included 707 contrast-enhanced T1 welghted images. 3D classification based on DenseNet model showed the best result in predicting WHO tumor grade (accuracy 83%, AUC 0.95). Other authors reported similar results for other methods. CONCLUSION: The first results of our study confirmed the fundamental possibility of grading axial contrast-enhanced T1 images according to the 2007 WHO classes using deep learning models.

[Artificial intelligence technologies in clinical neurooncology]. / Tekhnologii iskusstvennogo intellekta v klinicheskoi neiroonkologii.

Neurooncology in the 21st century is a complex discipline integrating achievements of fundamental and applied neurosciences. Complex processes and data in clinical neurooncology determine the necessity for advanced methods of mathematical modeling and predictive analytics to obtain new scientific knowledge. Such methods are currently being developed in computer science (artificial intelligence). This review is devoted to potential and range of possible applications of artificial intelligence technologies in neurooncology with a special emphasis on glial tumors. Our conclusions may be valid for other areas of clinical medicine.

3D pseudo-continuous arterial spin labeling-MRI (3D PCASL-MRI) in the differential diagnosis between glioblastomas and primary central nervous system lymphomas.

PURPOSE: The aim of the study was to compare the parameters of blood flow in glioblastomas and primary central nervous system lymphomas (PCNSLs), measured by pseudo-continuous arterial spin labeling MRI (3D PCASL), and to determine the informativeness of this method in the differential diagnosis between these lesions. METHODS: The study included MRI data of 139 patients with PCNSL (n = 21) and glioblastomas (n = 118), performed in the Burdenko Neurosurgical Center. No patients received chemotherapy, hormone therapy, or radiation therapy prior to MRI. On the 3D PCASL perfusion map, the absolute and normalized values of tumor blood flow were calculated in the glioblastoma and PCNSL groups (maxTBFmean and nTBF). RESULTS: MaxTBFmean and nTBF in the glioblastoma group were significantly higher than those in the PCNSL group: 168.9 ml/100 g/min versus 65.6 and 9.3 versus 3.7, respectively (p < 0.001). Arterial spin labeling perfusion had high sensitivity (86% for maxTBFmean, 95% for nTBF) and specificity (77% for maxTBFmean, 73% for nTBF) in the differential diagnosis between PCNSL and glioblastomas. Blood flow thresholds were 98.9 ml/100 g/min using absolute blood flow values and 6.1 using normalized values, AUC > 0.88. CONCLUSION: The inclusion of 3D PCASL in the standard MRI protocol can increase the specificity of the differential diagnosis between glioblastomas and PCNSL.

3D pCASL-perfusion in preoperative assessment of brain gliomas in large cohort of patients.

The aim of the study was to evaluate the role of pseudocontinuous arterial spin labeling perfusion (pCASL-perfusion) in preoperative assessment of cerebral glioma grades. The study group consisted of 253 patients, aged 7-78 years with supratentorial gliomas (65 low-grade gliomas (LGG), 188 high-grade gliomas (HGG)). We used 3D pCASL-perfusion for each patient in order to calculate the tumor blood flow (TBF). We obtained maximal tumor blood flow (maxTBF) in small regions of interest (30 ± 10 mm2) and then normalized absolute maximum tumor blood flow (nTBF) to that of the contralateral normal-appearing white matter of the centrum semiovale. MaxTBF and nTBF values significantly differed between HGG and LGG groups (p < 0.001), as well as between patient groups separated by the grades (grade II vs. grade III) (p < 0.001). Moreover, we performed ROC-analysis which demonstrated high sensitivity and specificity in differentiating between HGG and LGG. We found significant differences for maxTBF and nTBF between grade III and IV gliomas, however, ROC-analysis showed low sensitivity and specificity. We did not observe a significant difference in TBF for astrocytomas and oligodendrogliomas. Our study demonstrates that 3D pCASL-perfusion as an effective diagnostic tool for preoperative differentiation of glioma grades.

Artificial Intelligence in Neurosurgery: a Systematic Review Using Topic Modeling. Part I: Major Research Areas.

In recent years, the number of scientific publications on artificial intelligence (AI), primarily on machine learning, with respect to neurosurgery, has increased. The aim of the study was to conduct a systematic literature review and identify the main areas of AI applications in neurosurgery. METHODS: Using the PubMed search engine, we found and analyzed 327 original articles published in 1996-2019. The key words specific to each topic were identified using topic modeling algorithms LDA and ARTM, which are part of the AI-based natural language processing. RESULTS: Five main areas of neurosurgery, in which research into AI methods are underway, have been identified: neuro-oncology, functional neurosurgery, vascular neurosurgery, spinal neurosurgery, and surgery of traumatic brain injury. Specifics of these studies are characterized. CONCLUSION: The information presented in this review can be instrumental in planning new research projects in neurosurgery.

Artificial Intelligence Technologies in Neurosurgery: a Systematic Literature Review Using Topic Modeling. Part II: Research Objectives and Perspectives.

The current increase in the number of publications on the use of artificial intelligence (AI) technologies in neurosurgery indicates a new trend in clinical neuroscience. The aim of the study was to conduct a systematic literature review to highlight the main directions and trends in the use of AI in neurosurgery. METHODS: Using the PubMed search engine, 327 original journal articles published from 1996 to July 2019 and related to the use of AI technologies in neurosurgery, were selected. The typical issues addressed by using AI were identified for each area of neurosurgery. RESULTS: The typical AI applications within each of the five main areas of neurosurgery (neuro-oncology, functional, vascular, spinal neurosurgery, and traumatic brain injury) were defined. CONCLUSION: The article highlights the main areas and trends in the up-to-date AI research in neurosurgery, which might be helpful in planning new scientific projects.

[Early predictive biomarkers of posttraumatic epilepsy]. / Rannie prediktivnye biomarkery posttravmaticheskoi epilepsii.

Traumatic brain injury (TBI) affects about 50 million people in the world every year. Posttraumatic epilepsy (PTE) is a significant complication of TBI of any severity. PTE occurs in 20% of patients with TBI. Treatment of patients with PTE is particularly difficult due to obvious tendency towards drug resistance. Currently, there are no validated predictive biomarkers for PTE. Development of a system of validated predictive markers would improve PTE prediction quality and therapeutic approach for these patients. This review is devoted to the current data on the most perspective predictive biomarkers of PTE for clinical practice.

Terahertz dielectric spectroscopy of human brain gliomas and intact tissues ex vivo: double-Debye and double-overdamped-oscillator models of dielectric response.

Terahertz (THz) technology offers novel opportunities in the intraoperative neurodiagnosis. Recently, the significant progress was achieved in the study of brain gliomas and intact tissues, highlighting a potential for THz technology in the intraoperative delineation of tumor margins. However, a lack of physical models describing the THz dielectric permittivity of healthy and pathological brain tissues restrains the further progress in this field. In the present work, the ex vivo THz dielectric response of human brain tissues was analyzed using relaxation models of complex dielectric permittivity. Dielectric response of tissues was parametrized by a pair of the Debye relaxators and a pair of the overdamped-oscillators - namely, the double-Debye (DD) and double-overdamped-oscillator (DO) models. Both models accurately reproduce the experimental curves for the intact tissues and the WHO Grades I-IV gliomas. While the DD model is more common for THz biophotonics, the DO model is more physically rigorous, since it satisfies the sum rule. In this way, the DO model and the sum rule were, then, applied to estimate the content of water in intact tissues and gliomas ex vivo. The observed results agreed well with the earlier-reported data, justifying water as a main endogenous label of brain tumors in the THz range. The developed models can be used to describe completely the THz-wave - human brain tissues interactions in the frameworks of classical electrodynamics, being quite important for further research and developments in THz neurodiagnosis of tumors.

[Analysis of phosphatidylcholines alterations in human glioblastoma multiform tissues ex vivo]. / Analiz izmenenii sostava fosfatidilkholinov v glioblastomakh cheloveka ex vivo.

Significant metabolism alteration is accompanying the cell malignization process. Energy metabolism disturbance leads to the activation of de novo synthesis and beta-oxidation processes of lipids and fatty acids in a cancer cell, which becomes an indicator of pathological processes inside the cell. The majority of studies dealing with lipid metabolism alterations in glial tumors are performed using the cell lines in vitro or animal models. However, such conditions do not entirely represent the physiological conditions of cell growth or possible cells natural variability. This work presents the results of the data obtained by applying ambient mass spectrometry to human glioblastoma multiform tissues. By analyzing a relatively large cohort of primary and secondary glioblastoma samples, we identify the alterations in cells lipid composition, which accompanied the development of grade IV brain tumors. We demonstrate that primary glioblastomas, as well as ones developed from astrocytomas, are enriched with mono- and diunsaturated phosphatidylcholines (PC 26:1, 30:2, 32:1, 32:2, 34:1, 34:2). Simultaneously, the saturated and polyunsaturated phosphatidylcholines and phosphatidylethanolamines decrease. These alterations are obviously linked to the availability of the polyunsaturated fatty acids and activation of the de novo lipid synthesis and beta-oxidation pathways under the anaerobic conditions in the tumor core.

[Influence of cerebral hyperthermia on intracranial pressure and autoregulation of cerebral circulation in patients with acute brain injury]. / Vliyanie tserebral'noi gipertermii na vnutricherepnoe davlenie i autoregulyatsiyu mozgovogo krovotoka u patsientov s ostroi tserebral'noi patologiei.

Background. Hyperthermia is a common symptom in ICU patients with brain injury. OBJECTIVE: To study the effect of hyperthermia on intracranial pressure (ICP) and cerebral autoregulation (Prx). MATERIAL AND METHODS: There were 8 patients with acute brain injury, signs of brain edema and intracranial hypertension. Cerebral autoregulation was assessed by using of PRx. ICP, CPP, BP, PRx were measured before and during hyperthermia. We have analyzed 33 episodes of cerebral hyperthermia over 38.30 C. Statistica 10.0 (StatSoft) was used for statistical analysis. RESULTS: Only ICP was significantly increased by 6 [3; 11] mm Hg (p<0.01). In patients with initially normal ICP, hyperthermia resulted increase of ICP in 48% of cases (median 24 [22; 28] mm Hg). In patients with baseline intracranial hypertension, progression of hypertension was noted in 100% cases (median 31 [27; 32] mm Hg) (p<0.01). Hyperthermia resulted intracranial hypertension regardless brain autoregulation status. CONCLUSION: Cerebral hyperthermia in patients with initially normal ICP results intracranial hypertension in 48% of cases. In case of elevated ICP, further progression of intracranial hypertension occurs in 100% of cases. Cerebral hyperthermia is followed by ICP elevation in both intact and impaired cerebral autoregulation.

[Falcine chondrosarcoma (case report and literature review)]. / Redkoe nablyudenie fal'ks-khondrosarkomy (klinicheskii primer i obzor literatury).

Chondrosarcoma is a rare malignancy composed of transformed cells of cartilage. This cancer is characterized by slow growth. Almost 75% of intracranial chondrosarcomas are observed on the skull base and grow from bone synchondrosis. Other rarer localizations of tumor are cerebral falx, tentorium cerebelli, vascular plexuses of the ventricles, fourth ventricle, convexital surface of the brain, etc. In this manuscript, we report treatment of patient with falcine chondrosarcoma.

Capability of physically reasonable OCT-based differentiation between intact brain tissues, human brain gliomas of different WHO grades, and glioma model 101.8 from rats.

Optical coherence tomography (OCT) of the ex vivo rat and human brain tissue samples is performed. The set of samples comprises intact white and gray matter, as well as human brain gliomas of the World Health Organization (WHO) Grades I-IV and glioma model 101.8 from rats. Analysis of OCT signals is aimed at comparing the physically reasonable properties of tissues, and determining the attenuation coefficient, parameter related to effective refractive index, and their standard deviations. Data analysis is based on the linear discriminant analysis and estimation of their dispersion in a four-dimensional principal component space. The results demonstrate the distinct contrast between intact tissues and low-grade gliomas and moderate contrast between intact tissues and high-grade gliomas. Particularly, the mean values of attenuation coefficient are 7.56±0.91, 3.96±0.98, and 5.71±1.49 mm-1 for human white matter, glioma Grade I, and glioblastoma, respectively. The significant variability of optical properties of high Grades and essential differences between rat and human brain tissues are observed. The dispersion of properties enlarges with increase of the glioma WHO Grade, which can be attributed to the growing heterogeneity of pathological brain tissues. The results of this study reveal the advantages and drawbacks of OCT for the intraoperative diagnosis of brain gliomas and compare its abilities separately for different grades of malignancy. The perspective of OCT to differentiate low-grade gliomas is highlighted by the low performance of the existing intraoperational methods and instruments.

[Comparative analysis of mono- and bipolar pyramidal tract mapping in patients with supratentorial tumors adjacent to motor areas: comparison of data at 64 stimulation points]. / Sravnitel'nyi analiz potochechnogo mono- i bipolyarnogo kartirovaniya piramidnogo trakta u patsientov s supratentorial'nymi opukholyami, prilezhashchimi k motornym zonam golovnogo mozga: sravnenie dannykh v 64 tochkakh stimulyatsii.

OBJECTIVE: To compare monopolar and bipolar mapping in point-by-point fashion by using of threshold amperage, frequency of positive motor responses and the number of muscles involved in response. MATERIAL AND METHODS: A prospective non-randomized study included 14 patients with supratentorial tumors who underwent surgery in 2018-2019. All neoplasms were localized within 2 cm from the motor cortex and pyramidal tract. Age of patients ranged from 25 to 74 years. There were 9 women and 5 men. Eight patients had malignant glioma (grade III - 4, grade IV - 4), 6 patients - meningioma. Motor functions were assessed in all patients before and after surgery (1, 7 days and 3 months later) by using of a 5-point scale. In addition to routine neurophysiological monitoring, comparative mono- and bipolar mapping of the pyramidal tract within the bed of excised tumor was carried out at the end of surgery. The points of motor responses were marked. Comparative analysis of mono- and bipolar stimulation at identical points included threshold amperage, frequency of positive motor responses and the number of muscles involved in response (leg, forearm, hand, facial muscles). Brain MRI was performed in early postoperative period for assessment of resection quality. RESULTS: There were 64 points of motor responses in 14 patients. The number of these points ranged from 2 to 8 per a patient (mean 5 points). Motor responses were recorded in 57 points during monopolar and bipolar stimulation, in other 7 points - only during monopolar stimulation. Amperage of monopolar stimulation was 3-15 mA, bipolar stimulation - 2.5-25 mA. Threshold amperage (7.37 mA for monopolar stimulation and 8.88 mA for bipolar stimulation; p=0.12), frequency of positive motor responses and the number of muscles involved in response (p=0.1 and p=0.73) were similar. Seven (50%) patients had neurological deterioration in early postoperative period (4 patients with glial tumors and 3 patients with meningiomas). At the same time, only 2 patients (14.3%) had persistent neurological deficit (both patients with infiltrative meningioma). According to postoperative MRI in T1+C mode, resection volume was 100% in 1 patient with contrast-enhanced glioma and 94% in another one. According to FLAIR MRI data, resection volume exceeded 70% in 2 patients with non-enhancing glioma and less than 70% in 2 patients. Meningioma resection volume was estimated according to postoperative T1+C MRI data and made up over 90% in 4 patients. CONCLUSION: Monopolar stimulation is a reliable method of pyramidal tract identification in supratentorial brain tumor surgery.

[The role of lipids in the classification of astrocytoma and glioblastoma using MS tumor profiling]. / Rol' lipidov pri klassifikatsii astrotsitomy i glioblastomy pri pomoshchi mass-spektrometricheskogo profilirovaniia opukholei.

Express MS identification of biological tissues has become a much more accessible research method due to the application of direct specimen ionization at atmospheric pressure. In contrast to traditional methods of analysis employing GC-MS methods for determining the molecular composition of the analyzed objects it eliminates the influence of mutual ion suppression. Despite significant progress in the field of direct MS of biological tissues, the question of mass spectrometric profile attribution to a certain type of tissue still remains open. The use of modern machine learning methods and protocols (e.g., "random forests") enables us to trace possible relationships between the components of the sample MS profile and the result of brain tumor tissue classification (astrocytoma or glioblastoma). It has been shown that the most pronounced differences in the mass spectrometric profiles of these tumors are due to their lipid composition. Detection of statistically significant differences in lipid profiles of astrocytoma and glioblastoma may be used to perform an express test during surgery and inform the neurosurgeon what type of malignant tissue he is working with. The ability to accurately determine the boundaries of the neoplastic growth significantly improves the quality of both surgical intervention and postoperative rehabilitation, as well as the duration and quality of life of patients.

[Clinical and MRI predictors of coma duration, intensive care and outcome of traumatic brain injury]. / Klinicheskie i magnitno-rezonansnye tomograficheskie prediktory dlitel'nosti komy, ob"ema intensivnoi terapii i iskhodov pri cherepno-mozgovoi travme.

OBJECTIVE: This research is aimed to study the clinical and MRI predictors of coma duration, the intensity of critical care, and outcome of traumatic brain injury (TBI). MATERIAL AND METHODS: The data from 309 patients with TBI of varying severity were included in the analysis, of whom 257 (86.7%) were treated in the intensive care unit (ICU), including 196 (63.4%) patients admitted in a comatose state lasting longer than 1 day. All patients underwent brain MRI within 21 days after the injury. MRI findings were classified according to MRI grading scale of brain damage level and localization proposed previously. RESULTS: The proposed MRI grading significantly correlated with the Glasgow coma (GCS, r=-0.67; p<0.0001) and Glasgow outcome (0.69; p<0.001) scores in the entire group. In a subgroup of comatose patients (GCS<9) it correlated with coma duration (r=0.52; p<0.0001). Spearman correlation analysis showed a significant relationship between the MRI classification and a number of parameters: ICU length of stay (r=0.62; p<0.0001), the duration of artificial ventilation (r=0.47; p<0.0001), the rate of artificial ventilation, sedatives, analgesics, mannitol, hypertonic saline and vasopressors usage (p<0.01). These data confirm the relationship between higher grades of MRI classification (deep brain damage) and the need for the escalation of intensive care main components. CONCLUSION: Our results support the hypothesis that the levels and localization of brain damage, estimated by the proposed MRI grading scale, might be predictors of coma duration, intensity and duration of intensive care, and TBI outcomes. A prognosis based on clinical and neuroimaging data comparison can be valuable for planning and efficient use of the hospital beds and ICU resources, for optimizing the patient flow and timing of patient transfer to neurorehabilitation facilities.

[Multicystic transformation of the post-radiation necrosis zone of the brain. A case report and literature review]. / Mul'tikistoznaya transformatsiya zony postluchevogo nekroza golovnogo mozga. Klinicheskoe nablyudenie i obzor literatury.

Post-radiation cyst of the brain is a rare complication that often arises many years after irradiation for head and neck neoplasms. The majority of the articles devoted to this problem are small samples or case reports. Nevertheless, the overall number of these patients is steadily increasing. The feature of post-radiation cysts is gradual enlargement followed by general cerebral and focal symptoms and ineffectiveness of therapy. Some patients with clinically significant post-radiation cysts can require surgical treatment. Insertion of Ommaya reservoir may be preferred in these patients. In some cases, this method is ineffective and more complex surgeries may be required. The objectives of this report were to analyze literature data and describe the patient with multiple recurrent brain cysts after previous irradiation for frontotemporal skin melanoma. Twenty-seven publications were analyzed for the period from 1997 to 2018. According to the literature, the incidence of post-radiation cysts varies from 0.4% to 28%, timing of occurrence - from 2 months to 27 years. These values significantly depend on the underlying disease. We report a 27-year-old patient who admitted to the Burdenko Neurosurgery Center with focal and general cerebral symptoms after irradiation for skin melanoma of the right frontotemporal region. These symptoms were caused by cystic lesion of the right temporal and frontal lobes. Surgical treatment consisted in insertion of 2 Ommaya reservoirs. This approach ensured complete regression of the cyst in the right temporal lobe and mild decrease of the cyst in the right frontal lobe.

[The prognostic value of mri-classification of traumatic brain lesions level and localization depending on neuroimaging timing]. / Prognosticheskoe znachenie MRT-klassifikatsii urovnei i lokalizatsii travmaticheskogo povrezhdeniia mozga v zavisimosti ot srokov obsledovaniia patsientov.

OBJECTIVE: The aim of this study was to estimate the prognostic value of magnetic resonance imaging (MRI) classification of traumatic brain lesion localization and levels in patients with a brain injury of various severity in a few days to three weeks after the injury. MATERIAL AND METHODS: The cohort of 278 patients with traumatic brain injury (TBI) of various severity aged 8-74 y.o. (average -31.4±13.8, median - 29 (21.3; 37.0) was included in the analysis. The severity of TBI at admission varied from 3 to 15 Glasgow coma scores (GCS) (average - 8±4, median - 7 (5; 12). The main indications and conditions for MRI were: inconsistency between computed tomography (CT) data and neurological status, the necessity to clarify the location and type of brain damage, the absence of metal implants, the stabilization of the patient's vital functions, etc. MRI was performed during the first three weeks after the injury using T1, T2, T2-FLAIR, DWI, T2*GRE, SWAN sequences. The damage to the brain was classified according to 8 grades depending on the lesion levels (cortical-subcortical level, corpus callosum, basal ganglia and/or thalamus, and/or internal, and/or external capsules, uni- or bilateral brain stem injury at a different level). Outcomes were assessed by the Glasgow outcome scale (GOS) 6 months after injury. RESULTS: The significant correlations were found for the entire cohort between MRI grading and TBI severity (by GCS) and outcome (by GOS) of the injury (R=-0.66; p<0.0001; R=-0.69; p<0.0001, respectively). A high accuracy (77%), sensitivity (77%) and specificity (76%) of the proposed MRI classification in predicting injury outcomes (AUC=0.85) were confirmed using the logistic regression and ROC analysis. The assessment of MRI-classification prognostic value in subgroups of patients examined during the first, second, and third weeks after injury showed significant correlations between the GCS and the GOS as well as between MRI-grading and GCS, and GOS in all three subgroups. In the subgroup of patients examined during the first 14 days after the injury, the correlation coefficients were higher compared with those obtained in a subgroup examined 15-21 days after the injury. The highest correlations between MRI grading, TBI severity, and the outcome were found in the subgroup of patients who underwent MRI in the first three days after the injury (n=58). CONCLUSION: The proposed MRI classification of traumatic brain lesion levels and localization based on the use of different MR sequences reliably correlated with the clinical estimate of TBI severity by GCS and the outcomes by GOS in patients examined during the first three weeks after injury. The strongest correlation was observed for patients examined during the first three days after the injury.

[Diffusion kurtosis imaging in diffuse axonal injury]. / Izmeneniia parametrov diffuzionno-kurtozisnoi MRT u patsientov s diffuznym aksonal'nym povrezhdeniem.

Diffuse axonal injury (DAI) is one of the most severe traumatic brain injuries. The availability of neuroimaging biomarkers for monitoring expansion of traumatic brain injury in vivo is a topical issue. PURPOSE: To evaluate novel neuroimaging biomarkers for monitoring brain injury using diffusion kurtosis imaging (DKI) in patients with severe diffuse axonal injury. MATERIAL AND METHODS: DKI data of 12 patients with severe DAI (11 patients with a Glasgow Coma Scale (GCS) score of ≤ 8 and 1 patient with a GCS score of 9) and 8 healthy volunteers (control group) were compared. MRI examination was performed 5 to 19 days after injury; 7 of the 12 patients underwent repeated MRI examinations. We assessed the following parameters: mean, axial, and radial kurtosis (MK, AK, RK, respectively) and kurtosis anisotropy (KA) of the white and gray matter; fractional anisotropy (FA), axonal water fraction (AWF), axial and radial extra-axonal diffusion (AxEAD and RadEAD, respectively), and tortuosity (TORT) of the extra-axonal space) of the white matter. Regions of interest (ROIs) were set bilaterally in the centrum semiovale, genu and splenium of the corpus callosum, anterior and posterior limbs of the internal capsule, putamen, thalamus, midbrain, and pons. RESULTS: A significant reduction in KA (p<0.05) in most of ROIs set on the white matter was revealed. AK was increased (p<0.05) not only in the white matter but also in the putamen and thalamus. A significant reduction in MK with time was observed when the first and second DKI data were compared. AWF was reduced in the centrum semiovale and peduncles. The TORT parameter was decreased (p<0.05) in the majority of ROIs in the white matter, with the most pronounced changes occurring in the genu and splenium of the corpus callosum. CONCLUSION: DKI provides novel data about microstructural injury in DAI and improves our knowledge of brain trauma pathophysiology. DKI parameters should be considered as potential biomarkers of brain injury and potential predictors of the outcome.

[Phosphorus (P) magnetic resonance spectroscopy for evaluation of brain tissue metabolism and measuring non-invasive pH. A study involving 23 volunteers. Part I]. / Fosfornaia (R) MR-spektroskopiia v otsenke énergeticheskogo metabolizma mozgovoi tkani i neinvazivnom izmerenii pH. Issledovanie 23 dobrovol'tsev. Chast' I.

Evaluation of brain metabolism is an important part in examination of brain lesions. Phosphorus magnetic resonance spectroscopy opens up great opportunities for studying the energy metabolism and allows noninvasive examination of metabolic processes occurring both in healthy and in pathologic brain tissue by obtaining a spectrum of phosphorus-containing metabolites involved in the turnover of cell membrane phospholipids. The technique presented in this paper was used to conduct 31P MR spectroscopy and to estimate the ratio between the peaks of the main metabolites and intracellular pH of the healthy brain tissue of 23 volunteers in the age group under 30 years old in clinical settings. Based on the recorded stable phosphorus spectra of metabolites of the healthy brain tissue, the value of intracellular pH (6.963±0.044) and the ratio of the main PME/PDE peaks (1.17±0.20) were calculated. The database was created to subsequently analyze the metabolic changes in brain tissue spectra in norm and in pathology, as well as the intracellular pH variations that have diagnostic and prognostic value.

[Modern aspects of reconstructive surgery of skull defects]. / Sovremennye aspekty rekonstruktivnoi khirurgii defektov cherepa.

The aim of this study is to systematize the modern methods used for reconstruction of extensive and complex skull defects. Special attention is paid to computer technologies, including 3D imaging and CAD/CAM. Laser-based stereolithography is thoroughly reviewed among other additive technologies. We present our view of the problem associated with proper timing of cranioplasty and choice of materials for it. Complications of skull defect reconstruction are also discussed.