[Perifocal edema and glymphatic system dysfunction: quantitative assessment based on diffusion tensor magnetic resonance imaging]. / Peritumoroznyi otek i disfunktsiya glimfaticheskoi sistemy golovnogo mozga: kolichestvennaya otsenka na osnove diffuzionno-tenzornoi MRT.

BACKGROUND: Pathogenesis of peritumoral cerebral edema is unclear and potentially associated with glymphatic system dysfunction. Diffusion tensor MRI (DT-MRI) with analysis of ALPS (Analysis along the Perivascular Space) index may be valuable for assessment of edema. This approach visualizes fluid flow along perivascular spaces of deep cerebral veins. OBJECTIVE: To assess glymphatic system function in supratentorial tumors and healthy volunteers using DT-MRI. MATERIAL AND METHODS: There were 52 patients (59% men) aged 43 (28-64) years with supratentorial tumors (meningioma - 20, grade 3-4 glioma - 15, metastases - 9, lymphoma - 8). Tumors and perifocal edema did not involve deep cerebral veins. The control group included 6 healthy volunteers aged 34-66 years. MRI protocol (Signa HDxt, 3 T) contained standard T1, T2, T2FLAIR, DWI and post-contrast T1 (3D BRAVO). DT-MRI had the following parameters: TR=10 000 ms, TEmin=102 ms, FOV=240 mm, isotropic voxel size 3×3×3 mm3, 60 directions of diffusion gradients. Measurements were carried out at b-factor 0 and 1000 s/mm2. Analysis was carried out in the ReadyView software. RESULTS: Right- and left-sided ALPS indices were similar in the control group (p=0.917). Perifocal edema (regardless of histological type of tumor) in the ipsilateral hemisphere was accompanied by significantly lower ALPS index (p<0.005), while these values in contralateral (intact) hemisphere were similar in both groups (p=0.7). CONCLUSION: We found significantly lower ALPS index in deep parts of the affected hemisphere in patients with perifocal edema. These data can indicate the role of glymphatic system dysfunction in pathogenesis of this pathology.

[Factors influencing peritumoral edema in meningiomas: CT- and MRI-based quantitative assessment]. / Peritumoroznyi otek pri meningiomakh i faktory, vliyayushchie na ego formirovanie: kolichestvennaya otsenka na osnove KT i MRT.

Background. Meningiomas may be accompanied by peritumoral edema. Incidence and pathogenesis of edema are nor clearly established. Prevalence and severity of edema vary significantly in patients with meningiomas similar in various parameters. OBJECTIVE: To assess peritumoral edema in intracranial meningiomas and factors influencing incidence and severity of this process. MATERIAL AND METHODS: There were 126 patients (69% women) aged 19-76 years (median 53), who were diagnosed with 142 meningiomas. Patients underwent surgery (n=111) and radiotherapy (n=15) in 2016-2018. The MRI protocol included T1, T2, T2-FLAIR, DWI and post-contrast T1-weighted images in three projections, diffusion tensor MRI in 27 cases and MR spectroscopy in 21 patients. RESULTS: Peritumoral edema was detected in 46% (n=66) of cases including 21 (31%) patients with severe edema. The ALPS index was 1.510±0.1931 in meningiomas without edema and 1.308±0.19 in those with edema (p=0.014). There was positive correlation between edema, dimensions and uneven contours of meningioma, as well as negative correlation with CSF cleft sign. Blood flow velocity was higher in atypical and anaplastic meningiomas with edema (p=0.03). Other signs (localization, histological variant, malignancy grade, characteristics of MR signal, peaks of the main metabolites, diffusion and perfusion parameters of tumor) did not significantly affect peritumoral edema in patients with meningiomas (p>0.05). CONCLUSION: Diffusion tensor tomography with ALPS index revealed significant effect of glymphatic system dysfunction on peritumoral edema. Large meningioma with uneven contours increased the risk of peritumoral edema, while CSF cleft sign reduced this risk. Other factors did not affect cerebral edema in meningiomas.

[Machine learning for resting state fMRI-based preoperative mapping: comparison with task-based fMRI and direct cortical stimulation]. / Primenenie mashinnogo obucheniya dlya predoperatsionnogo kartirovaniya po dannym funktsional'noi magnitno-rezonansnoi tomografii pokoya: sravnenie so stimul-zavisimoi funktsional'noi magnitno-rezonansnoi tomografiei i pryamoi elektricheskoi stimulyatsiei kory.

OBJECTIVE: To develop a system for preoperative prediction of individual activations of motor and speech areas in patients with brain gliomas using resting state fMRI (rsfMRI), task-based fMRI (tb-fMRI), direct cortical stimulation and machine learning methods. MATERIAL AND METHODS: Thirty-three patients with gliomas (19 females and 14 males aged 19 - 540) underwent DCS-assisted resection of tumor (19 ones with lesion of motor zones and 14 patients with lesions of speech areas). Awake craniotomy was performed in 14 cases. Preoperative mapping was performed according to special MRI protocol (T1, tb-fMRI, rs-fMRI).Machine learning system was built on open source data from The Human Connectome Project. MR data of 200 healthy subjects from this database were used for system pre-training. Further, this system was trained on the data of our patients with gliomas. RESULTS: In DCS, we obtained 332 stimulations including 173 with positive response. According to comparison of functional activations between rs-fMRI and tb-fMRI, there were more positive DCS responses predicted by rs-fMRI (132 vs 112). Non-response stimulation sites (negative) prevailed in tb-fMRI activations (69 vs 44). CONCLUSION: The developed method with machine learning based on resting state fMRI showed greater sensitivity compared to classical task-based fMRI after verification with DCS: 0.72 versus 0.66 (p<0.05) for identifying the speech zones and 0.79 versus 0.62 (p<0.05) for motor areas.

[Comparison of resting state and task-based functional MRI in preoperative mapping in patients with brain gliomas]. / Sravnenie funktsional'noi magnitno-rezonansnoi tomografii v sostoyanii pokoya i stimul-zavisimoi funktsional'noi magnitno-rezonansnoi tomografii v predoperatsionnom kartirovanii u patsientov s gliomami golovnogo mozga.

OBJECTIVE: To analyze and compare the results of cerebral cortex mapping with task-based (tb-fMRI) and resting-state functional MRI in patients with glioma of eloquent cortical areas. MATERIAL AND METHODS: There were 55 patients (24 men and 31 women aged 24 - 74 years, median 39) with glial tumors. In 26 patients, the tumor was located in motor areas. Twenty-nine patients had lesions of Broca and Wernicke's areas. All patients underwent preoperative tb-fMRI and rs-fMRI. Then, resection of tumor was carried out in all cases. RESULTS: Comparison of fMRI and rs-fMRI activation maps was assessed by calculating the Dice coefficient for inclusive speech and motor cortex masks and exclusive masks without brainstem, cerebellum, subcortical nuclei. Inclusive Dice coefficient for motor cortex ranged from 0.11 to 0.50, for speech cortex - from 0.006 to 0.240 (p<0.05). In case of exclusive masks, this value ranged from 0.15 to 0.55 for motor cortex and from 0.004 to 0.205 for speech cortex (p<0.05). CONCLUSION: When comparing the results of cortical mapping in patients with glial tumors, the use of hemispheric exclusive and inclusive masks did not significantly increase activation maps matching. Probably, low degree of correspondence was associated with different genesis of activations, as well as with high variability of speech cortex.

[Periventricular changes following hydrocephalus: quantitative MR-based assessment of tissue characteristics]. / Periventrikulyarnye izmeneniya pri gidrotsefalii: kolichestvennaya otsenka tkanevykh kharakteristik metodom magnitno-rezonansnoi tomografii.

OBJECTIVE: To study tissue characteristics of periventricular white matter in patients with open hydrocephalus using DWI MRI and their correlations with CSF flow parameters. MATERIAL AND METHODS: MRI was performed in 55 patients (35 women and 20 men) with open normal pressure hydrocephalus, as well as 16 patients with malignant occlusive hydrocephalus and interstitial edema (control group). We determined the correlations between severity of hydrocephalus, periventricular lesions and CSF flow parameters considering MR data. Dimensions of ventricular system were assessed using the Evans' index, periventricular changes - using visual four-level scale with calculation of apparent diffusion coefficient (ADC) and fractional anisotropy coefficient (FA). RESULTS: Among patients with open hydrocephalus, ACD range for periventricular white matter was 1.57±0.15·10-3 mm2/s in subgroup of patients without periventricular changes (n=29) and 1.62±0.11×10-3 mm2/s in patients with periventricular changes (n=26). In the control group, mean ADC was 1.76±0.18·10-3 mm2/s (p<0.05). In patients with open hydrocephalus, FA coefficient in the areas of periventricular changes was 0.70-0.80, in case of occlusive hydrocephalus - 0.68-0.82. There was a significant relationship between the Evans' index and CSF pulsation velocity amplitude, Evans' index and stroke volume, Evans' index and cerebral aqueduct cross-sectional area in patients with open hydrocephalus. Periventricular changes were pronounced in patients with open hydrocephalus and Evans' index > 0.4 (p<0.05). CONCLUSION: According to MR data, periventricular changes in patients with open hydrocephalus differ from true periventricular interstitial edema following occlusive hydrocephalus. Severity of periventricular changes in patients with open hydrocephalus depends on patient age and width of the ventricles, but does not correlate with CSF flow parameters. In our opinion, periventricular changes are associated with dysfunction of glymphatic system. Further research is required to study the functioning of glymphatic system and related processes.

[Endoscopic transnasal approach in surgical treatment of petrous temporal bone cholesteatoma extending towards the clivus. Three clinical observations and literature review]. / Endoskopicheskii transnazal'nyi dostup v khirurgicheskom lechenii kholesteatom piramidy visochnoi kosti, rasprostranyayushchikhsya v oblast' skata. Tri klinicheskikh nablyudeniya i obzor literatury.

Petrous temporal bone Cholesteatoma is widely described in the literature and accounts for up to 9% of all neoplasms of this localization. These cholesteatomas rarely spread towards the clivus. Isolated clival cholesteatomas are described only as single cases. There is currently no consensus on the choice of surgical approach for resection of similar neoplasms. OBJECTIVE: To demonstrate the possibilities of endoscopic transnasal approach in surgery for clival and petrous cholesteatoma. MATERIAL AND METHODS: This article presents 3 clinical cases: 2 patients with apical cholesteatoma of petrous part of temporal bone extending to the clivus and 1 patient with massive petrous temporal bone cholesteatoma extending towards the clivus according to the classification of Sanna M. All patients underwent endoscopic transnasal surgery. RESULTS AND CONCLUSION: In our opinion, endoscopic transnasal approach is optimal for resection of similar neoplasms. Total and subtotal resection was performed in 2 and 1 case, respectively. However, there are certain limitations of this approach in accessing the most lateral parts of the neoplasm. Nevertheless, endoscopic transnasal approach ensures resection of petrous temporal bone cholesteatoma extending to the clivus without the risk of damage to acoustic-facial cranial nerves. It is especially significant in patients without their baseline dysfunction.

Feasibility of generalised diffusion kurtosis imaging approach for brain glioma grading.

PURPOSE: An accurate differentiation of brain glioma grade constitutes an important clinical issue. Powerful non-invasive approach based on diffusion MRI has already demonstrated its feasibility in glioma grade stratification. However, the conventional diffusion tensor (DTI) and kurtosis imaging (DKI) demonstrated moderate sensitivity and performance in glioma grading. In the present work, we apply generalised DKI (gDKI) approach in order to assess its diagnostic accuracy and potential application in glioma grading. METHODS: Diffusion scalar metrics were obtained from 50 patients with different glioma grades confirmed by histological tests following biopsy or surgery. All patients were divided into two groups with low- and high-grade gliomas as grade II versus grades III and IV, respectively. For a comparison, trained radiologists segmented the brain tissue into three regions with solid tumour, oedema, and normal appearing white matter. For each region, we estimated the conventional and gDKI metrics including DTI maps. RESULTS: We found high correlations between DKI and gDKI metrics in high-grade glioma. Further, gDKI metrics enabled introduction of a complementary measure for glioma differentiation based on correlations between the conventional and generalised approaches. Both conventional and generalised DKI metrics showed quantitative maps of tumour heterogeneity and oedema behaviour. gDKI approach demonstrated largely similar sensitivity and specificity in low-high glioma differentiation as in the case of conventional DKI method. CONCLUSION: The generalised diffusion kurtosis imaging enables differentiation of low- and high-grade gliomas at the same level as the conventional DKI. Additionally, gDKI exhibited higher sensitivity to tumour heterogeneity and tissue contrast between tumour and healthy tissue and, thus, may contribute as a complementary source of information on tumour differentiation.

[Breast cancer metastasis into a giant hormone-inactive pituitary adenoma adenoma. (Clinical case and literature review)]. / Metastaz raka molochnoi zhelezy v gigantskuiu gormonal'no-neaktivnuiu adenomu gipofiza. (Klinicheskoe nabliudenie i obzor literatury).

Brain metastases of various types of cancer are diagnosed in 8-10% of all cancer patients. In the world literature, only 30 cases of cancer metastasis to the pituitary adenoma are described. This article presents yet another observation of a patient with breast cancer metastasis into the hormone-inactive pituitary adenoma at the Burdenko neurosurgical center, Russia The patient underwent endoscopic endonasal transsphenoid removal of the neoplasm. During microscopy and immunohistochemical studies of the biopsy, two types of tissue (pituitary adenoma and cancer metastasis) with different Ki-67 treated surgically (1% and over 40%) were found.

[Transsphenoid extirpation of pituitary adenomas in patients with McCune-Albright syndrome (two cases from practice and literature review)]. / Transsfenoidal'noe udalenie adenom gipofiza u patsientov s sindromom MakK'iuna-Olbraita (dva sluchaia iz praktiki i obzor literatury).

INTRODUCTION: McCune-Albright Syndrome is a rare genetic disease characterized by the formation of fibrous osteodysplasia foci of various localization, including the bones of skull base. Having a gross lesion of the main bone body and the simultaneous formation of the pituitary adenoma, its transnasal removal becomes very difficult. MATERIAL AND METHODS: Two clinical observations are presented where at patients with the classic manifestation of McCune-Albright syndrome we were able to successfully remove somatotropinomas with endoextrasellar growth. In both cases the presence of visual disorder was the indication for surgery. RESULTS: Despite pronounced deviations in the anatomy of the skull base bones in both cases we managed to access the Turkish saddle. Removal of the pituitary tumor did not differ from standard surgery. Improved vision after surgery was observed in two patients. Tumors were removed subtotally and clinical and biochemical remission of acromegaly was not achieved. In both cases, the tumors had morphological signs of atypia. Patients continued to receive therapy with somatostatin analogues and radiation. CONCLUSION: The possibility of performing transnasal surgery in this category of patients using specific instruments and intraoperative navigation is shown.

[Correlation of intracranial pressure and diameter of the sheath of the optic nerve by computed tomography in severe traumatic brain injury]. / Korreliatsiia vnutricherepnogo davleniia i diametra obolochki zritel'nogo nerva po dannym komp'iuternoi tomografii pri tiazheloi cherepno-mozgovoi travme.

BACKGROUND: Noninvasive techniques to evaluate intracranial pressure (ICP) are important for everyday practice in intensive care and neurosurgery departments. CT data can be used to evaluate the optic nerve sheath diameter (ONSD) and, indirectly, the ICP value. The ONSD value is an additional criterion in deciding on invasive monitoring of ICP. AIM: To analyze a correlation between CT-based ONSD and the results of invasive measurements of ICP in patients with severe traumatic brain injury. MATERIAL AND METHODS: The study evaluated 41 patients with severe traumatic brain injury within the first 48 h after injury. Invasive monitoring of ICP (Codman & Shurtlett, MA, USA) was performed during 7±1.7 days. ONSD was measured using axial CT scans (CereTom, Neurologica Danvers, MA, USA) with a slice thickness of 2.5 mm. The ONSD value was measured at a distance of 3 mm from the posterior eyeball contour. The patients were allocated in a group with normal ICP (10 patients) and a group with high ICP (31 patients). ONSD served as an ICP classifier. The data were processed using ROC analysis. RESULTS: According to the CT data, the optimal threshold ONSD value was 6.35 mm in patients in the acute TBI period. The sensitivity was 0.93 (95% СI 0.84-1.00), the specificity was 0.80 (95% СI 0.50-1.00), and AUC was 0.87 (95% СI 0.69-1.00). CONCLUSION: We found a correlation between the CT-based ONSD and the median ICP (R=0.32, p<0.05). An ONSD value of 6.35 mm and more is one of the signs of previous or existing ICP.

[The algorithm for surgical treatment of skull base tumors invading the craniovertebral junction].

UNLABELLED: Surgical treatment of skull base tumors invading the craniovertebral junction is a complex medical problem due to a high rate of adverse postoperative outcomes in these patients. AIM: The study aim was to optimize surgical treatment in patients with skull base tumors invading the craniovertebral junction. MATERIAL AND METHODS: A comparative analysis of 2 groups of patients was performed. The study group included 28 patients with skull base and craniovertebral junction chordomas who underwent single-stage surgery, including posterior occipitospondylodesis and tumour resection using the transoral and combined transoral and transnasal approaches, in the period between 2000 and 2015. The control group included 21 patients with the same pathology who underwent microsurgery using the transoral approach without occipitospondylodesis in the period between 1990 and 2009. RESULTS: Most of the patients in both groups were operated on at late disease stages when they presented with gross clinical signs. The use of single-stage occipitospondylodesis and transoral skull base tumor removal significantly (compared to the control group) extends indications for surgical treatment of skull base tumors, which were previously considered unresectable, and provides better results. CONCLUSION: New surgical techniques significantly increase the completeness of tumor resection, decrease the rate of postoperative complications, accelerate the rehabilitation process, and improve the patient's quality of life.

[3D-TOF MR-angiography with high spatial resolution for surgical planning in insular lobe gliomas].

UNLABELLED: Despite the obvious progress in modern neurosurgery, surgery for glial tumors of the insular lobe is often associated with a high risk of postoperative neurological deficit, which is primarily caused by damage to perforating arteries of the M1 segment of the middle cerebral artery. OBJECTIVE: The work is aimed at evaluating the effectiveness of high resolution time-of-flight (3D-TOF) MR angiography in imaging of medial and lateral lenticulostriate arteries and determining their relationship to tumor edge in patients with gliomas of the insula. MATERIAL AND METHODS: 3D-TOF MR angiography data were analyzed in 20 patients with primarily diagnosed cerebral gliomas involving the insula. All patients underwent non-contrast enhanced 3D-TOF MR angiography. In 6 cases, 3D-TOF MRA was performed before and after contrast enhancement. RESULTS: 3D-TOF angiography before intravenous contrast injection was capable of visualizing the medial lenticulostriate arteries in 19 patients (95% of all cases) and lateral lenticulostriate arteries in 18 patients (90% of all cases). Contrast-enhanced 3D-TOF angiography allows for better visualization of both the proximal and distal segments of lenticulostriate arteries. Three variants of relationship between the tumor and lenticulostriate arteries were identified. Variant I: the tumor grew over the arteries without their displacement in 2 cases (10% of the total number of observations); variant II: the tumor caused medial displacement of arteries without growing over them in 11 cases (55% of the total number of observations); variant III: the tumor partially grew over and displaced arteries in 2 cases (10%). In 25% of cases (5 patients), tumor was poorly visualized on 3D-TOF MR angiograms because their signal characteristics did not differ from those of the medulla (tumor tissue was T1 isointense). As a result, it was impossible to determine the relationship between the tumor and lenticulostriate arteries. CONCLUSION: High spatial resolution time-of-flight MR angiography can be recommended for preoperative imaging of lenticulostriate arteries to plan the extent of neurosurgical resection in patients with glial tumors of the insular lobe.

[SCT perfusion in the diagnosis of sellar and parasellar tumors].

UNLABELLED: The study is devoted to the use of a minimally invasive method of SCT perfusion for the differential diagnosis of sellar and pаrаsellar tumors. Given a wide differential diagnostic range of tumors occurring in this area, the tumor perfusion indicators were used as an auxiliary diagnostic criterion. MATERIAL AND METHODS: The study analyzed outcomes in 115 patients with various tumors of the sellar area who underwent surgery or biopsy for histological verification of the diagnosis. RESULTS: The statistically significant differences were obtained for certain groups of tumors based on the values of hemodynamic parameters (p<0.05) that enable, with a high confidence, making a conclusion on the histologic type of most tumors. CONCLUSION: These findings demonstrated that SCT perfusion is a highly informative method of the preoperative differential diagnosis of these tumors. The sensitivity and specificity of SCT perfusion in the study were 100% and 81.2%, respectively.

[Assessment of optic nerve decompression efficiency in resection of sellar region meningiomas via intradural subfrontal approach].

In this article we analyze results of the different variants of the optic nerve transcranial decompression in cases with different chiasmal region tumors. We operate 70 patient with different type meningioma (tuberculum sella, shenoid wings, anterior clinoid, optic canal), pituitary adenoma and one case with tuberculoma (we operate it thinking on meningioma, but histology was unexpected). Groups of the patients. Group1. 20 patients with pituitary adenoma with cavernous sinus invasion. It was our "pre-endoscopic" period when we frequently operated adenomas by transcranial approach. In this 20 patients we used intra-extradural Dolenc approach to cavernous sinus. In that cases we removed anterior clinoid process and decompressed optic canal. Here we use the results of surgery in this group for showing the possibility of using high speed drill for the optic canal decompression - for showing it safety. On our opinion this type of optic canal decompression is radical and safe but superfluous for the optic canal invasion by the meningioma. Group 2. 19 patients with meningioma. In that cases we partially unroofed optic canal by Kerrison and additionally we cut the falciform ligament. Group 3. 31 patients with meningioma. It's our "main" group. Here we made intradural wide unroofing the optic canal by high speed drill. Additionaly we cut the falciform ligament and open the dural sheet of the optic nerve. We propose this methodic like sufficient, safe and useful. In this cases we frequently saw the tumor spread inside the dural sheet of the optic nerve, without seeing it on the MRI. A lot of cases in this group was a recurrent after previous meningioma removal. Like a control groups we use two. Group 4. 11 cases with meningioma. In that cases we removed tumor from optic canal without any decompression. It was our archive group - we made this type of surgery before starting optic canal decompression. This group shows the risks of any manipulation with fixed optic nerves without optic canal decompression. Group 5. 31 case with meningioma. In this cases we saw the optic canal invasion by the tumor but we didn't try to decompress it. It was our archive group - we made this type of surgery before starting optic canal decompression. We use this group for found out the risks of canal decompression. This group shows the poor perspectives for the vision in optic canal invasion by the tumor without it decompression. We analyze the results of surgery on the day of discharge and on catamnesis - we decide that the optic nerves need time to recovery. We analyzed the results of surgery in patients with 3 types of the visual dysfunction: moderate (1.0-0.5), hard (0.5-0.1), decompensating (0.1-0). For showing the real risks and effectivety of any type of decompression and surgery without decompression we look for results in patients with decompensating of visual functions. For statistical analyses we use Fisher criteria which used in small series. We statistically showed that any attempts of tumor removal form the optic canal is more risky than decompression. Also we found a tendency that wide intradural decompresstion made by high speed drill with additional falciform ligament cutting and the dural sheet opening is more effective and safe than opening the optic canal by Kerrisson. This technique also could be used during the transcranial surgery for the other type of pathology particularly in cases with short optic nerves and prefixed chiasm - it gives the mobility for the nervesand decreased the nerve damaging.

[Experience of surgical management of trigeminal schwannomas that simultaneously spread to the middle and posterior cranial fossae].

INTRODUCTION: trigeminal schwannomas account for 0.07-0.36% of all intracranial tumors and 0.8-8% of all intracranial schwannomas. Different surgical approaches are used depending on the topographic anatomical variant of the tumor. Dumbbell-shaped tumors that spread both to the middle and posterior cranial fossae are the most challenging ones in terms of their resection. MATERIAL AND METHODS: Five patients with dumbbell-shaped trigeminal schwannomas were operated on at the Burdenko Neurosurgical Institute in 2011-2013. In four cases, tumor resection comprised two stages using the retrosigmoid suboccipital approach (RSA) and lateral extended transsphenoidal endoscopic approach (LETEA); in one case, the tumor was resected in a single session through the LETEA. If there were pronounced symptoms affecting the brainstem and/or cerebellum, tumor resection from the posterior cranial fossa through RSA was resected at the first stage (3 cases). If no symptoms were observed, tumor resection from the middle cranial fossa through LETEA was used as the first stage (2 cases). RESULTS: After two surgical stages, total, subtotal, and partial tumor resection was performed (one case each). Total tumor resection from the middle cranial fossa was achieved through LETEA in two cases. Aggravation of ipsilateral paresis of the craniocerebral nerve VI was observed after the surgery in two cases. No cases of nasal liquorrhea were observed after transnasal surgery. In one case, the cavernous segment of the internal carotid artery was damaged during LETEA, thus requiring endovascular occlusion of the damaged vessel to be performed. CONCLUSION: LETEA is an effective approach that allows resection of tumors from the middle cranial fossa and the cavernous sinus. Combined with RSA, this approach can be used for two-stage resection of dumbbell-shaped trigeminal schwannomas.

[The use of three-dimensional reconstruction in neuroroentgenology]. / Issledovanie trekhmernoi rekonstruktsii v neirorentgenologii.

The recent advent of spiral computed tomography (CT) and new fast impulse sequences in magnetic resonance imaging (MRI) into diagnostic practice has expanded the range of brain and spinal diseases detected by these techniques. This has also expanded the field of use of three-dimensional images obtained on the basis of mathematical algorithms for processing CT and MRI data. At present, not only neurotraumatology and maxillofacial surgery are the main areas in applying three-dimensional models. Spatial representation of bulky formations of the brain, their mutual location with the adjacent anatomic structures (with ventricles of the brain) may be useful in choosing a surgical access and in planning the scope of a surgical intervention. CT- and MR-angiographies that are now successfully used in diagnosing vascular pathology, providing high-solution angiograms not only can be competitive with direct angiography, but can replace this sophisticated study for vascular stenotic processes in the neck. Moreover, analyzing the internal surface of the vascular wall on the basis of virtual endoscopy may be useful in direct surgical and endovascular interventions. The purpose of this study was to pool long-term experience in using three-dimensional images in the qualitative improvement of diagnostic methods in examining neurosurgical patients and to define the most promising lines of their use in neurosurgery as a whole.