[A 20-year experience in surgical treatment of steno-occlusive lesion of craniocervical arteries at the Burdenko Neurosurgical Center]

INTRODUCTION

Surgical treatment of cerebral ischemia at the Burdenko Neurosurgical Center for the period from 1999 to 2019 is analyzed in the paper. The details of the treatment strategy in patients with steno-occlusive lesion of craniocervical arteries followed by cerebral ischemia developed over 20 years are discussed in the article. We have analyzed the features of surgical interventions on the major craniocervical arteries in a neurosurgical clinic and the results of this treatment.

OBJECTIVE

To demonstrate management of various lesions of major cerebral arteries in modern neurosurgical vascular hospital.

MATERIAL AND METHODS

In total, there were 3098 interventions on the major cerebral arteries in 2527 patients for this period. Mean age of patients ranged from 1.5 to 91 years (58±14 years). Interventions included open reconstructions of the carotid arteries (2031 surgeries), reconstructions of the vertebrobasilar arteries (135 surgeries), brain revascularization (658 surgeries), excision of the tumors of neurovascular bundle on the neck compressing carotid arteries (51 interventions). Endovascular interventions were performed in 223 cases and consisted of angioplasty and stenting of the extracranial segments of craniocervical arteries (185 surgeries), stenting of the intracranial arteries (30 surgeries) and endovascular thrombextraction (8 cases). Staged surgeries were performed in 541 patients (22.3%).

RESULTS

Favorable outcomes were obtained in 87.6% of cases, satisfactory results - in 9% of patients. Clinical deterioration due to long-term postoperative complications and recurrent strokes occurred in 2.9% of cases. Postoperative morbidity rate was 4.6%, persistent neurological deficit developed in 2.6% of cases. Mortality rate was 0.5%.

CONCLUSION

Surgical treatment of stenotic and occlusive lesion of the major cerebral arteries is an interdisciplinary problem. Solution of this issue is closely associated with technological progress, new discoveries in normal and pathological physiology, as well as clinical researches. Individualized choice of surgical approach is one the main modern trends of neurosurgical approach to this problem. At the same time, own surgical experience is the most important factor determining the results of arterial reconstructions.

[Clinical and MRI predictors of coma duration, intensive care and outcome of traumatic brain injury]

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.

[Positron emission tomography with 11C-methionine in primary brain tumor diagnosis]

OBJECTIVE

To investigate the variations in ¹¹C-methionine uptake in the intact brain tissue and in glial brain tumors of different types.

MATERIAL AND METHODS

Forty patients (21 men, 19 women) with gliomas, Grade I-IV, underwent ¹¹C-methionine PET-CT and contrast-enhanced MRI. Standardized uptake value (SUV), tumor-to-normal (T/N) ratios and tumor volume were analyzed.

RESULTS

The high inter-subject variability was detected in the intact brain tissue (SUV in the frontal lobe (FL) varies from 0.47 to 1.73). Amino acid metabolism was more active in women than in men (FL SUV 1.32±0.22 and 1.05±0.24, respectively). T/N ratio better differentiates gliomas by the degree of anaplasia compared to SUV. Gliomas of Grade III (T/N=2.64±0.98) were significantly different (p<0.05) from those of Grade IV (T/N=3.83±0.75). The lowest level of methionine uptake was detected in diffuse astrocytomas (T/N=1.52±0.57), which was lower than with anaplastic astrocytomas (T/N=2.34±0.77, p<0.05).

CONCLUSIONS

¹¹C-methionine PET-CT was informative in the high/low degree of malignancy differentiation (T/N 1.66±0.71 for Grade I-II and 3.18±1.06 for Grade III-IV, p<0.05). The method was also useful in separating astrocytomas of Grade II and III. The considerable variation of SUV in the intact brain tissue as well as the difference in uptake between selected areas of the brain were revealed.

[Resting-state fMRI in preoperative non-invasive mapping in patients with left hemisphere glioma]

Maximum resection and preservation of neurological function are main principles in surgery of brain tumors, especially glial neoplasms with diffuse growth. Therefore, exact localizing of eloquent brain areas is an important component in surgical planning ensuring optimal resection with minimal postoperative neurological deficit. Functional MRI is used to localize eloquent brain areas adjacent to the tumor. This paper is an initial stage in analysis of resting-state fMRI in assessment of functional changes of neuronal activity caused by brain gliomas of different localization. We report two patients with glial tumors localized within the precentral gyrus of the left hemisphere and near speech area. Considering data of task-based and resting-state fMRI, as well as direct cortical stimulation, we propose a methodology for assessing the overlap of activations obtained by these methods.

[Modern standards for magnetic resonance imaging of the brain tumors]

Neuroimaging is essential in survey of patients with brain tumors. An important objectives of neuroimaging are highly reliable non-invasive diagnosis, treatment planning and evaluation of treatment outcomes. Magnetic resonance imaging (MRI) is one of the modern neuroimaging methods. This technique ensures analysis of structural cerebral changes, vascular and metabolic characteristics of brain tumors. It is necessary to standardize imaging parameters and unify protocols and methods considering a widespread use of MRI for brain tumors. In our practice, we use our own experience, world literature data and evidence-based international guidelines on the diagnosis of various brain diseases. The purpose of this review is to study the modern principles of magnetic resonance imaging in adults with brain tumors in neurosurgical practice.

[Theranostics for glioblastoma with monoclonal antibodies to the epidermal growth factor receptor]

A review is devoted to analysis of the prospects of theranostics for multiform glioblastoma with monoclonal antibodies to the epidermal growth factor receptor (EGFR). Treatment of various malignancies demonstrated high potential of the use of EGFR. However, in case of glioblastoma, the effectiveness of monoclonal antibodies to EGFR is constrained by the absence of informative criteria for assessing the effectiveness of diagnosis and treatment of disease.

[Convulsive syndrome as a manifestation of acute cerebral damage due to paradoxical air embolism in neurosurgical patients. Series of clinical cases and literature review]

Introduction

Paradoxical air embolism (PAE) is a rare potentially fatal complication followed by entering of air emboli from the right cardiac chambers and pulmonary artery to large circulation circle.

Objective

To analyze five patients who underwent neurosurgical intervention complicated by PAE and early postoperative convulsive syndrome.

Material and methods

There were five patients who developed early postoperative convulsive syndrome after previous neurosurgery in sitting position complicated by PAE. Convulsive syndrome required intensive care at the ICU. MRI confirmed ischemic foci de novo outside the zone of surgical intervention in all cases. All patients underwent video-EEG monitoring in order to select anticonvulsant therapy and evaluate its effectiveness. The authors were able to match the epileptogenic focus in the cerebral cortex with MRI data. Available literature data devoted to the problem of convulsive syndrome after neurosurgery complicated by PAE were analyzed.

Results

The focus of epileptiform activity coincided with one of the foci of hyperintense MR signal in all cases.

Conclusion

Video-EEG monitoring is advisable in patients with impaired consciousness who underwent neurosurgery complicated by PAE.

[microsurgery 'burr hole' for intracranial tumors and mesial temporal lobe epilepsy]

PURPOSE

In recent years, neurosurgery has been characterized by a clear tendency towards the development of minimally invasive and less traumatic surgical approaches. To minimize the degree of injury to the brain tissue, we have proposed burr hole-based microsurgical approaches.

MATERIAL AND METHODS

In the period between February 2016 and February 2019, more than 500 microsurgical interventions were performed through a 14 mm burr hole using a technique that we called burr-hole microneurosurgery; to date, 200 of these have been analyzed. The age of patients varied from 16 to 79 years (median, 38 years). Female patients predominated - 1.6:1. Surgery for intracranial lesions with various locations was performed in 176 cases; in the remaining 24 cases, patients with hippocampal sclerosis underwent selective amygdalohippocampectomy.

RESULTS

Various surgical approaches were used: transcortical approach in 81 (40.5%) cases; retro-sigmoid approach in 38 (19%); sub-temporal approach in 32 (16%); infratentorial supracerebellar approach in 25 (12.5%); interhemispheric approach in 17 (8.5%); telovelar approach in 5 (2.5%); trans-eyebrow approach in 2 cases. The resection degree was evaluated in 167 patients with planned maximum tumor resection. Resection was total and almost total in 145 (87%) patients, subtotal in 15 (9%), and partial in 7 (4%). The surgery duration varied from 35 to 300 min (mean, 80 min). The extubation time after surgery ranged from 5 min to 5 days (mean, 70 min). In 195 (97.5%) cases, patients were verticalized within the first 3 days after surgery.

CONCLUSION

The proposed burr hole technique enables successful surgery in patients with various intracranial pathologies, using a smaller trepanation window compared to that in keyhole surgery. The proposed burr hole technique minimizes injury to the brain substance, significantly reduces patient's exposure to anesthesia, and decreases the entire duration of surgery.

[Intraoperative vascular fluorescence in cerebral glioblastomas and vascular histological features]

5-ALA intraoperative fluorescence is widely used in surgery of brain tumors for intraoperative demarcation of boundaries and more total resection because 5-ALA metabolites are not accumulated in the intact brain and vascular tissues. Given this fact, it was hypothesized that fluorescence of vessels in the immediate vicinity of a brain tumor may indicate their infiltration by tumor cells as a potential pathway for their dissemination and as a factor for continued tumor growth after surgery and adjuvant therapy.

PURPOSE

Identification of fluorescent vessels located near cerebral gliomas, with a histological description of their structure, relationships with the tumor, and potential invasion of the walls by tumor cells.

MATERIAL AND METHODS

A prospective cohort study included 14 patients with malignant supratentorial gliomas, aged 20 to 78 years. Five patients were operated on due to continued tumor growth. Two hours before surgery, all patients received 5-ALA orally. During surgery, a microscope (Carl Zeiss OPMI Pentero, Germany) with a fluorescent module (BLUE-400) was used. In all cases, molecular-genetic and immunohistochemical examinations of the tumor material were performed. During surgery, fluorescent vessels, after evaluating their functional significance, were also resected for histological examination.

RESULTS

Glioblastoma and anaplastic astrocytoma were verified in 10 and 4 patients, respectively. In 4 out of 10 glioblastoma cases, vessels with homogeneous or fragmentary fluorescent walls were detected in the tumor bed after resection of most of the tumor; in patients with anaplastic astrocytomas, vascular fluorescence was not observed. In the four vascular samples with intraoperatively detected wall fluorescence, tumor invasion into the vascular layers was revealed in all cases. These patients underwent an immunohistochemical examination with monoclonal antibodies to the glial GFAP marker, which clearly identified areas of ingrowth of tumor cells into the vascular wall.

CONCLUSION

5-ALA intraoperative fluorescence is a fundamentally new approach in the rapid diagnosis of tumor-infiltrated blood vessels. Invasion of tumor cells to intact vessels may be a mechanism of tumor progression and dissemination. Additional resection of fluorescent vessels may affect the radicalness of surgical treatment, but requires a mandatory assessment of their functional significance.

[Multicystic transformation of the post-radiation necrosis zone of the brain. A case report and literature review]

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.

[Modern trends in diagnosis and surgical treatment of moyamoya disease]

This review is devoted to moyamoya disease. It is a rare chronic steno-occlusive cerebrovascular disease. However, moyamoya disease is increasingly diagnosed by neurosurgeons in our country. Unlike atherosclerotic lesions of cerebral arteries, pathogenesis and course of this disease are much more complex and variable. Therefore, specialists often have certain difficulties in diagnosis, management and treatment of these patients. To date, a large number of surgical interventions have been proposed for the treatment of moyamoya disease. Revascularization approaches include direct procedures (extra-intracranial microanastomoses), indirect methods (synangioses) and combined revascularization. The purpose of the review is to systematize current literature data on the pathogenesis, diagnosis, clinical patterns and surgical treatment of patients with moyamoya disease. results Outcomes of surgical revascularization and the role of its various components in combined approach are under particular attention.

[Pseudoprogression of intracranial pilocytic astrocytomas and other low-grade gliomas. Literature review and case report]

Tumor pseudoprogression is characterized by temporary tumor enlargement following radiotherapy with subsequent stabilization or regression without additional treatment. This phenomenon has been comprehensively described in patients with malignant gliomas. However, this phenomenon has not been sufficiently studied in patients with low-grade gliomas including pilocytic astrocytomas. In recent years, more and more researches devoted to this problem have appeared in the literature. It seems relevant to conduct a meta-analysis of these data in the modern literature.

[Combination of double and indirect two-sided revascularization of the brain in the treatment of moyamoya disease]

An adult patient with progressive chronic cerebral ischemia associated with moyamoya disease who underwent combined revascularization of both cerebral hemispheres in step-by-step fashion is reported in the article. The feature of this case is a large volume of revascularization procedures with double-barrel extra-intracranial anastomoses combined with indirect synangioses. This surgical approach ensured early postoperative development of extensive collateral network and complete compensation of impaired cerebral circulation. Particular attention is paid to description and discussion of preoperative diagnosis, the choice of surgical treatment, as well as the features of surgical technique. The advantages and disadvantages of this approach are discussed in comparison with literature data.

[Diffusion kurtosis imaging in diffuse axonal injury]

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.

Proton 3D MR spectroscopy in the diagnosis of glial brain tumors

The purpose of this study was an assessment of the proton 3D MR spectroscopy efficacy in diagnosis of primary glial brain tumors.Material and methods. Sixty three patients aged from 20 to 60 years with primary glial brain tumors of varying degrees of malignancy were examined. The ratios of main metabolites indices were evaluated with following comparison with the metabolites obtained in gray and white matter of the opposite hemisphere.The ratios of main metabolites: Cho/Cr, NAA/Cr, Cho/NAA showed significant (p <0.005) differences in the groups of patients with low and high grade gliomas.Results. The obtained data proved the efficacy of the proton 3D MR-spectroscopy in predicting of the glial brain tumors malignancy.

[Phosphorus (P) magnetic resonance spectroscopy for evaluation of brain tissue metabolism and measuring non-invasive pH. A study involving 23 volunteers. Part 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.

[Orbital hemangiomas: capabilities of modern neuroradiological diagnostics]

MATERIAL AND METHODS

In the period from 2010 to 2016. 14 patients with cavernous hemangioma (CH) and 2 patients with capillary hemangioma (CapH) of the orbit were examined. The age of CH patients varied from 17 to 67 years (median, 53 years); 8 females and 6 males. The age of CapH patients was 35 and 54 years. All patients underwent surgery with subsequent histological verification. CT-perfusion was performed in 10 CH patients and 2 CapH patients according to a developed low-dose protocol (80 kV, 200 mAs, t_scan=40 s) with allowance for a target localizer (80 kV, 120 mAs) and at a maximum radiation dose of not more than 4.0 mZv. Neoplasm microcirculation was quantitatively assessed by calculating hemodynamic parameters: blood flow velocity (BFV), blood volume (BV), and mean transit time (MTT). MRI without and with contrast enhancement was performed in 11 CH patients and 2 CapH patients according to the ophthalmologic protocol (Signa GE, 3.0 T) accepted at the Institute: without contrast enhancement - T1, T2, and T2-FLAIR modes, T1 and T2 with a Fat Sat technique at a scan thickness of 3 mm, and DWI MRI; contrast enhancement - T1 (three projections) mode, including the Fat Sat technique. SWAN (n=2) and non-contrast MR perfusion ASL (n=3) were also used. Diffusion-weighted images (DWI) were processed with calculation of the apparent diffusion coefficient (ACD).

RESULTS

In all CH patients, CT-perfusion revealed low perfusion parameters of blood flow: BV_CH=0.86±0.37 mL/100 g, BFV_CH= 4.89±2.01 mL/100 g/min with a high mean transit time MTT_CH=10.13±3.05 s compared to the same parameters of blood flow in the normal white matter: CBV_NormWM=1.63±2.22 mL/100 g, CBFV_NormWM=9.72±3.13 mL/100 g/min, and MTT_NormWM=6.76±2.78 s. In CapH cases, significantly increased blood flow velocity and volume values and a low MTT value in the tumor were observed: BV_CapH=10.30±4.10 mL/100 g, BFV_CapH=119.72±53.13 mL/100 g/min, and MTT_CapH=4.35±1.79 s. In the case of orbital hemangiomas, optimal MRI modes were T1 and T2 with the Fat Sat technique, a scan thickness of 3 mm, and intravenous contrast enhancement. The revealed pattern of contrast agent accumulation by CH, initially in the central part and then in the periphery, may be a useful radiographic sign in the differential diagnosis with other orbital tumors.

CONCLUSION

Modern CT- and MRI-based diagnostics of orbital hemangiomas provides not only the exact location, size, and spread of the lesion but also reveals the characteristic structural features of these tumors, and the use of perfusion techniques visualizes hemodynamics of the tumors. CT-perfusion-based hemodynamic parameters of cavernous hemangiomas typical of this type of hemangiomas may be used in the differential diagnosis with other tumors of this location. The use of contrast enhancement and the Fat Sat technique with a scan thickness of not more than 3 mm is optimal for MRI diagnostics of orbital hemangiomas.

[3D proton MR spectroscopy of the gray and white brain matter. A study of 15 volunteers]

One of the important problems of modern diagnostics of brain diseases is detection of early lesions, which determines the choice of patient management and the disease outcome. The introduction of magnetic resonance imaging in practice has significantly improved the quality of diagnosis. Multivoxel proton magnetic resonance spectroscopy is an additional and clarifying technique enabling non-invasive examination of changes in brain metabolism in tumors as well as simultaneous acquisition of information on metabolism in surrounding tissues and in the intact brain matter. Along with single voxel MR spectroscopy (SV MRS) and 2D MRS (CSI Chemical Shift Imaging), 3D proton MRS (MRSI) has been increasingly used in clinical practice, which enables single-run acquisition of data on the metabolite composition for the entire volume of interest.

OBJECTIVE

To assess the possibility of using multivoxel 3D proton MRS in healthy volunteers without organic brain pathology.

MATERIAL AND METHODS

In this study, 15 volunteers without organic brain pathology were examined using the 3D ¹H-MRS.

CONCLUSION

3D proton MRS has proven to be an effective technique in studying the brain metabolism. One short-term series of examinations provided information on intact brain metabolism at different anatomical levels, which enabled their comparison both in spectral data and in parametric maps of the major metabolite distribution.

[The prognostic value of mri-classification of traumatic brain lesions level and localization depending on neuroimaging timing]

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 ASSESMENT OF BRAIN MICROSTRUCTURE. HEALTHY VOLUNTEERS MEASURMENTS

Aim:discover quantitative and qualitative variance of diffusion parameters in white and gray matter of healthyvolunteers brain. Discover correlation between diffusion and kurtosis parameters, find out if there is correlation between the parameters and aging microstructural changes.Materials and methods.14 healthy volunteers were investigated (9 men, 5 women; age from 21 to 55 years, mean 34). The volunteers were classified into two groups by age: 7 subjects who younger 35 (6 men and 1 woman, mean age 25) and 7 subjects who older 35 years (3 men and 4 women, mean age 44). We used 3.0 Tesla MRI (3.0T SignaHDxt, General Electric, USA) with 8 channel head coil, gradient strength 50 mT/m, slew rate 150 T/m/s. Diffusion imaging was based on echo planar “spin echo” sequence (SE EPI), TR = 10000 ms, TEmin = 102 ms, FOV = 240 mm, voxel size 3 × 3 × 3 mm3, 60 non-coplanar diffusion directions and three b-values: 0, 1000, 2500 s/mm2. Acquisition time of diffusion kurtosis imaging was 22 minutes. We excluded extracerebral areas on diffusion and kurtosis parametric maps using semi-automatic approach. After that, brain images were transformed to MNI152 space using affine method. Masks of 9 anatomical structures were applied to the transformed images. Diffusion and kurtosis values were measured in these structures.Results.Fractional anisotropy (FA) changed from 0.06 in lateral occipital cortex to 0.25 in cerebral white matter, kurtosis anisotropy (KA) changed from 0.03 to 0.14 in the same cerebral structures. Axial (AK), radial (RK) and mean kurtosis (MK) were minimal in superior frontal gyrus and maximal in cerebral white matter. AK changed from 0.55 to 0.72, RK changed from 0.62 to 1.05, MK from 0.59 to 0.88. Axial(AxEAD) and radial extra axonal water diffusion (RadEAD) were minimal in putamen and maximal in superior frontal gyrus. AxEAD was changing from 1.38 • 10–3 to 2.57 • 10–3, RadEAD from 1.03 • 10–3 to 2.34 • 10–3. Axonal water fraction (AWF) had minimal value 0,18 in superior frontal gyrus and maximal value 0.29 in cerebral white matter. Tortuosity (TORT) changed from 1.06 in lateral occipital cortex to 1.43 in cerebral white matter. There was significant difference between age groups in AWF, RK, RadEAD in putamen and in KA in superior temporal gyrus. Maximal correlation with age was in MK in superior temporal gyrus, anterior division. It was equal to 0.562.Conclusions:Diffusion kurtosis imaging is highly sensitive method of brain tissue microstructure assessment, which detects age-related changes.

[Dynamics of functional MRI and speech function in patients after resection of frontal and temporal lobe tumors]

RATIONALE

There are no studies on application of functional MRI (fMRI) for long-term monitoring of the condition of patients after resection of frontal and temporal lobe tumors.

PURPOSE

The study purpose was to correlate, using fMRI, reorganization of the speech system and dynamics of speech disorders in patients with left hemisphere gliomas before surgery and in the early and late postoperative periods.

MATERIAL AND METHODS

A total of 20 patients with left hemisphere gliomas were dynamically monitored using fMRI and comprehensive neuropsychological testing. The tumor was located in the frontal lobe in 12 patients and in the temporal lobe in 8 patients. Fifteen patients underwent primary surgery; 5 patients had repeated surgery. Sixteen patients had WHO Grade II and Grade III gliomas; the others had WHO Grade IV gliomas. Nineteen patients were examined preoperatively; 20 patients were examined at different times after surgery. Speech functions were assessed by a Luria's test; the dominant hand was determined using the Annette questionnaire; a family history of left-handedness was investigated. Functional MRI was performed on an HDtx 3.0 T scanner using BrainWavePA 2.0, Z software for fMRI data processing program for all calculations >7, p<0.001.

RESULTS

In patients with extensive tumors and recurrent tumors, activation of right-sided homologues of the speech areas cold be detected even before surgery; but in most patients, the activation was detected 3 months or more after surgery. Therefore, reorganization of the speech system took time. Activation of right-sided homologues of the speech areas remained in all patients for up to a year. Simultaneous activation of right-sided homologues of both speech areas, the Broca's and Wernicke's areas, was detected more often in patients with frontal lobe tumors than in those with temporal lobe tumors. No additional activation foci in the left hemisphere were found at the thresholds used to process fMRI data. Recovery of the speech function, to a certain degree, occurred in all patients, but no clear correlation with fMRI data was found.

CONCLUSION

Complex fMRI and neuropsychological studies in 20 patients after resection of frontal and temporal lobe tumors revealed individual features of speech system reorganization within one year follow-up. Probably, activation of right-sided homologues of the speech areas in the presence of left hemisphere tumors depends not only on the severity of speech disorder but also reflects individual involvement of the right hemisphere in enabling speech function. This is confirmed by right-sided activation, according to the fMRI data, in right-sided patients without aphasia and, conversely, the lack of activation of right-sided homologues of the speech areas in several patients with severe postoperative speech disorders during the entire follow-up period.

[Chiasm and optic nerve glioma manifested as hemorrhage (two clinical cases and a literature review)]

The article presents two rare clinical cases of low-grade (WHO grade I-II) glioma of the anterior visual pathway structures, the chiasm and optic nerves, in adults. The feature of these cases was the benign nature of a chiasm and optic nerve glioma in adults as well as its presentation in the form of hemorrhage to the tumor and parenchymal and subarachnoid space, which to some extent complicated making the correct diagnosis. Removal of an intracerebral hematoma and open tumor biopsy were performed in one case, and removal of a hematoma and partial tumor resection followed by radiotherapy were performed in the other case.

[MR tractography in diagnosis and choice of a neurosurgical approach to basal ganglia tumors]

We describe two cases of surgical treatment of well-circumscribed basal ganglia tumors. The choice of a neurosurgical approach to a deep tumor was based on the MR tractography data and depended on the course and dislocation extent of the corticospinal tract. MR tractography provides information on the course and dislocation or destruction extent of the corticospinal tract running in the internal capsule and brainstem and clarifies the exact location of a tumor within the basal ganglia. This information promotes the choice of an optimal approach for radical resection of well-circumscribed tumor, leading to improvement in neurological symptoms and patient's quality of life.

[Non-contrast ASL perfusion in preoperative diagnosis of supratentorial gliomas]

The purpose of this study was to investigate the potential of pseudocontinuous arterial spin labeling perfusion (pCASL) in assessing the degree of malignancy of brain gliomas at the preoperative stage. MATERIAL AND METHODS: The study included 126 patients aged 12-75 years with supratentorial gliomas of different malignancy (35 low-grade gliomas and 91 high-grade gliomas). The maximum tumor blood flow (TBF) was measured, and the normalized tumor blood flow (nTBF) was calculated relative to the intact semiovale white matter of the contralateral hemisphere. The TBF and nTBF indicators differed significantly between low-grade and high-grade glioma groups (p<0.001). When using TBF and nTBF in the differential diagnosis of low-grade and high-grade gliomas, the area under the ROC curve was 0.96 in both cases. Our findings suggest that 3D pCASL perfusion is an effective technique for preoperative differential diagnosis of low-grade and high-grade gliomas. The study was supported by the Russian Foundation for Basic Research (grant #18-315-00384).

[Evaluation of vascular reactivity to overcome limitations of neurovascular uncoupling in BOLD fMRI of malignant brain tumors]

The sensitivity of fMRI in identification of eloquent cortical centers in the case of large infiltrative growing tumors and pronounced peritumoral edema may be reduced or significantly limited in some cases. The main cause is an attenuated Blood-Oxygen-Level-Dependent response (BOLD) caused by pathological vascular reactivity and subsequent neurovascular uncoupling of fMRI. In our study, we attempted to overcome these limitations and increase the sensitivity of this technique in identification of eloquent cortical areas adjacent to brain tumors by using vasoreactivity features of a breath-holding test and including these data in the BOLD analysis. Local vasoreactivity using a breath-holding paradigm with the same block design of both motor and speech tests was determined in 5 healthy volunteers and 3 patients in the preoperative period (two patients with high grade gliomas and one patient with single metastasis). A coherence-based model was developed for analysis of BOLD fMRI, which took into account altered hemodynamics in peritumoral zones. Obtained coherence maps demonstrated clinically more significant activation zones that were not seen with standard methods of fMRI processing. Thus, neurovascular uncoupling that is known to affect the accuracy of the BOLD fMRI response adjacent to brain tumors may be partially overcome by including an independent measurement of vasoreactivity using a breath-holding test in the BOLD analysis.