Arterial spin labeling (ASL) allows the assessment of tissue perfusion and has advantages such as non-invasiveness and the ability to repeat examinations multiple times. This enables dynamic monitoring without contrast administration. This technique requires additional pre- and post-processing, complicating result acquisition. A promising trend is the assessment of brain perfusion changes for diagnosing ischemic stroke. Aim of the study was to evaluate a comprehensive dynamic perfusion change in the brain in patients in the early post-stroke recovery period and conditionally healthy volunteers by the ASL. Material and Methods. A prospective observation of two groups was performed. The control group included 20 conditionally healthy volunteers aged from 18 to 25 years (21.8 ± 2.65 years) (mean ± standard error of the mean), the study group ‒ 20 patients with verified ischemic stroke aged from 40 to 70 years (59.4 ± 9.2 years) on days 1–3, 7–10, and three months after disease onset. Perfusion indicators of gray and white matter of the lobes of the cerebral hemispheres (parietal, occipital, frontal, temporal) in visually intact areas of the brain were integrally evaluated. Perfusion values were also calculated in ipsilateral and contralateral regions of interest relative to the stroke focus. Results and discussion. The stroke focus shows a nonlinear dynamic of changes, starting from 19.86 ± 5.69 ml/100 g/ min on days 1–3, increasing to 27.57 ± 4.86 ml/100 g/min on days 7–10, and decreasing to 14.48 ± 3.66 ml/100 g/min by the 3–4 month, remaining low compared to visually intact areas and the control group. Perfusion in the visually intact area of the ipsilateral hemisphere in relation to the stroke focus is significantly (p < 0.05) reduced by 4–5 % on days 1–3 and 7–10 compared to other regions of interest. Meanwhile, there is a gradual increase in perfusion values in all analyzed regions from the first to the third examination. Conclusions. The ASL method allows for the quantitative assessment of the dynamics of cerebral perfusion in the early recovery period, with a significant (p < 0.001) reduction in tissue blood flow in the ischemic focus relative to the analyzed regions of interest and the control group. The intact area in the ipsilateral hemisphere in relation to the stroke focus shows dynamic growth from hypoperfusion to normoperfusion, which is related to the involvement of the brain as a whole organ.

Modern methods of neuroimaging make it possible to develop approaches for assessing intracranial pressure as a replacement for the “gold standard” of invasive monitoring. Aim of the study was to investigate the possibility of using magnetic resonance (MR) characteristics to assess the increase in intracranial pressure in patients with secondary intracranial hypertension. Material and methods. Group 1 – 40 patients with brain tumors, group 2 – 15 patients with communicating hydrocephalus, control group – 36 individuals. The patients underwent MRI with measurement and evaluation of the optic nerve sheath diameter (ONSD), the optochiasmal cistern and the pituitary gland vertical sizes, and tortuosity of the ON. Patients of the 2nd group underwent a phase-contrast MRI with an assessment of the velocity and volumetric characteristics of blood and cerebrospinal fluid flows with the calculation of the intracranial compliance index (ICC). Using the FreeSurfer program, the brain volumes were estimated. Results and discussion. A statistically significant increase in ONSD was found in the groups of patients compared with the control group (by 24 %, p < 0.05), decrease in the vertical size of the pituitary gland and an increase in the vertical size of the optochiasmal cistern (p < 0.05), as well as ICC lowering in group 2 (by 1.7 times, p < 0.05). Tortuosity of ON in group 1 was observed more often than in other groups. A statistically significant positive correlation between ONSD and brain volumes in group 1 (r = 0.55, p < 0.05) and a negative correlation between brain volumes and ICC in group 2 (r = –0.86, p < 0.05) has been found. Conclusions. Based on the presented results, we believe that the combined use of qualitative and quantitative MRI criteria can expand the diagnostic capabilities of non-invasive assessment of increased intracranial pressure.

Current research in the field of neuroimaging is focused on the possibilities of using data from various diffusion MR models: diffusion tensor visualization (DTI), diffusion-curtosis visualization (DKI), diffusion-spectral visualization (DSI), generalized q-sample visualization (GQI), Q-ball visualization (QBI) in the assessment reorganization of the brain. The purpose of this study is to compare the results of dynamic observation of post–stroke brain reorganization by diffusion MR models (DTI, DKI). Material and methods. Dynamic MR examination of the brain of 129 patients was performed on a Ingenia 3.0 T (Philips, Netherlands) on 1–3 days, 7–10 days, 3–4 months after the manifestation of stroke according to a routine protocol (DWI-EPI, FLAIR-SPIR, T2-WI, T1W-TFE) with DTI method. The stroke was verified and DTI, GQI, and DKI maps were built. Results and discussion It was showed that the fractional anisotropy (FA) of DTI significantly changed from 1–3 days to 7–10 days in the stroke area; the mean, axial and radial diffusions increased in the affected area over the three studies. For DKI model – the curtosis FA significantly changed in the lesion area by 3–4 months; the mean curtosis decreased by the second observation in the stroke area, axial curtosis decreased in the same area throughout all studies; radial kurtosis significantly increased in the affected area throughout the study. The results confirm the world data and also indicate that diffusion metrics can interpret the neuroplasticity of the brain in various diseases, however, this requires further study. The applied diffusion models indicated the reorganization of the ischemic area and the intact contralateral area. The use of diffusion models for the dynamic assessment is a promising direction in the study of the neuroplasticity mechanisms.

The research was aimed at analyzing modern algorithms for diagnosing lesions in multiple sclerosis on MRI images. Multiple sclerosis is a severe disease of the central nervous system and ranks first among the causes of disability in patients of young working age. In connection with the development of computer vision and machine learning technologies, the relevance of using these technologies for medical diagnostics is growing. Such approaches are necessary for the effective development and implementation of diagnostic systems using artificial intelligence. Modern algorithms and models for lesion segmentation were selected and implemented. Material and methods. The paper presents CV features of diagnosing multiple sclerosis on MRI images, existing data sets: ISBI-2015, MSSEG-2016, MSSEG-2021; existing algorithms and models for lesion segmentation: U-Net, nnU-Net, TransUnet, TransBTS, UNETR, Swin UNETR. Results and discussion. The architectures and models of nnU-Net, UNETR, Swin UNETR were trained and compared at ISBI2015 with various parameters and loss functions. Four MRI sequences were used: T2-WI, T2-FLAIR, PD, MPRAGE. Lesion segmentation was approved by certified experienced neuroradiologists. Conclusions. The approaches described in the paper including data processing, model training, and results analysis, focused on the selection and development of high-quality computer vision algorithms for identifying multiple sclerosis lesions in MRI images. Identification and segmentation of demyelination foci is a necessary step for diagnosing the disease, as well as for calculating and interpreting more meaningful indicators of disease severity and progression.

Introduction. Multiple sclerosis is a chronic immune-mediated disease of the central nervous system with disseminated foci of demyelination and progressive neurodegeneration; it is the most common demyelinating disease and the leading cause of disability of neurological patients of a young age, characterized by a wave-like course with alternating periods of remission and relapse. Currently, there is a discussion about the participation of vascular changes in the formation of neurological disorders and about the possibility of correction of therapeutic approaches in connection with the revealed microcirculatory disorders. Perfusion MRI allows you to evaluate hemodynamics at the capillary level in vivo. Purpose. To evaluate perfusion changes in foci of demyelination in multiple sclerosis using the method of dynamic susceptibility contrast (DSC). Materials and methods. The MR study was carried out on a super-high-angle MR-scanner «Ingenia» («Philips») 3 Tesla. The study included 30 healthy volunteers and 80 patients with demyelinating disease from 18 to 48 years old (average age was 34,6±8,02 years).Quantitative and qualitative assessment of perfusion indices in foci of demyelination was carried out. Results. In the active foci of demyelination, an increase in the speed and volume of cerebral blood flow is noted, the most pronounced changes in patients with clinically isolated syndrome. Inactive foci, marked hypoperfusion is noted. Discussion. Evaluation of cerebral perfusion allows a new look at the role of the vascular component in the formation of focal inflammatory changes in the brain in multiple sclerosis, which can determine a new direction of pathogenetic treatment. Conclusion. Perfusion data complements routine MRI and provides a comprehensive assessment of the neurovascular system.

Purpose — to study the possibilities of clinical application of MR-myelography techniques in static and dynamic modes in patients with various neurological and neurosurgical pathologies accompanied by CSF dynamics disorders. On the Philips 1.5 and 3.0 T MRI scanners, an extended protocol for examination of patients with cerebrospinal fluid disorders was presented. The protocol includes, in addition to routine sequences (T1-, T2-WI, FLAIR), thin-slice MP-myelography in a static mode (CSF-DRIVE, 3DMYUR) with soft tissues signal suppression. Also, a cinema-technique of MR myelography (CSF-PCA) in the optimal projection and a phase-contrast method with a quantitative assessment of the cerebrospinal fluid flow at the pathology level and at adjacent levels were performed. The assessment of the diagnostic significance of the proposed research protocol was carried out. The extended study protocol was applied in patients with idiopathic normotensive hydrocephalus, obstructive hydrocephalus, Chiari malformation type I, in patients with syringomyelia at the level of the cervical spinal cord and showed high efficiency in assessing of cerebrospinal fluid dynamics in patients with a neurological and neurosurgical profile. The use of extended approach allows to more fully evaluate the state of the cerebrospinal fluid system, the patency of the cerebrospinal fluid (the presence of additional septa / membranes, partial / complete stenosis and narrowing), as well as preand postoperative morpho-functional changes.

We report a rare case of decompensated chronic internal hydrocephalus in an adult patient. A 35-year-old woman experienced acute intracranial hypertension in 3 weeks after relief of postoperative inflammation in the oral cavity (tooth extraction). MRI revealed severe internal hydrocephalus. Third ventriculostomy was followed by significant clinical improvement. However, postoperative survey and subsequent neuroimaging confirmed no reduction of ventricular system. Thus, decompensation of chronic hydrocephalus following dental intervention and subsequent oral inflammation was assumed. Impaired venous outflow from the brain and destabilization of CSF circulation can be considered as a pathogenetic mechanism.

The aim of this literature review is to consider the range of different integral characteristics and indices, by which it can be possible to evaluate impaired hemodynamics and cerebrospinal fluid dynamics in the central nervous system according to radiation introscopy, including ultrasound and phase-contrast magnetic resonance imaging. Consideration is given to various volume-velocity and temporal parameters and the possibility of using the described characteristics to study joint blood and cerebrospinal fluid flows. Emphasis is laid on the analysis of the information provided by each of the indices and by the possibility of its clinical application. This expanded study of the interaction of fluids in the central nervous system will be able to give a better insight into the mechanisms involved in maintaining homeostasis in the brain.

Цель исследования – проанализировать особенности изменений магистрального и перфузионного кровотока при патологической извитости внутренней сонной артерии (ВСА) методами фазово-контрастной и перфузионной МРТ. Материал и методы. Исследование проведено на МР-томографе 1,5 T с использованием рутинного протокола, фазово-контрастной и перфузионной МР-ангиографии. Оценивались очаговые сосудистые изменения головного мозга, показатели объемной, линейной пиковой скоростей кровотока по ВСА и значения перфузионных характеристик (CBF, CBV, MTT) в ее бассейне. Результаты. Определены значения скоростных характеристик кровотока при деформации ВСА, сопровождающиеся появлением МР-признаков сосудисто-мозговой недостаточности; выявлена взаимосвязь достоверного снижения показателя объемной скорости кровотока и нарастания выраженности дисциркуляторной очаговой патологии головного мозга в группе патологии. Выявлены корреляционные связи между значениями объемной скорости магистрального кровотока и регио- нарной скоростью тканевого кровотока (кора лобной доли R=0,35, кора теменной доли R=0,62, белое вещество лобной доли R=0,32, белое вещество теменной доли R=0,33), что позволяет сделать вывод об умеренной силе (p<0,05) корреляционных связей выбранных показателей кровотока в случае дисциркуляторных очагов головного мозга на фоне патологической извитости ВСА. Заключение. Корреляционные связи между капиллярным и магистральным кровотоком демонстрируют возможность использования таких показателей, как объемная скорость кровотока и CBF, для оценки магистральной и тканевой гемодинамики при определении значимости патологической извитости ВСА. HTML

The accuracies of measuring the velocity field using clinical and research magnetic resonance imagers are compared. The flow velocity of a fluid simulating blood in a carotid artery model connected to a programmable pump was measured. Using phase-contrast magnetic resonance tomography, the velocity distributions in the carotid artery model were obtained and compared with the analytical solution for viscous liquid flow in a cylindrical tube (Poiseuille flow). It is found that the accuracy of the velocity measurement does not depend on the field induction and spatial resolution of the imagers.

OBJECTIVE:to determine differences in cerebrospinal fluid (CSF) flow velocities in patients with varying degrees of communicating hydrocephalus (CH) versus a group of healthy volunteers without hydrodynamic disorders.MATERIAL AND METHODS:The investigation enrolled 27 CH patients (17 and 10 patients with an Evans index of 0.31 and 0.46, respectively) and 62 healthy volunteers. Average, volumetric, and peak flow velocities were determined at different intracranial levels.RESULTS:Analysis of differences between the mean values indicated that the patients with CH were observed to have progressive cranial cavity CSF outflow obstruction that depended on the degree of dilation of the ventricular system and, probably, on impaired CSF reabsorption. These changes can provide an explanation for the clinical symptoms present in the patients and also serve as diagnostic criteria.CONCLUSION:The investigation showed that phase-contrast magnetic resonance imaging might be used to estimate the quantitative indicators of CSF in health and in varying degrees of CH. The velocity characteristics of antegrade and retrograde CSF flows are significantly different in health and in disease, which may be relevant to neurologists and neurosurgeons when planning therapy and surgery options.

To determine the difference in the velocity parameters of cerebrospinal fluid flow in patients with varying severity of communicating hydrocephalus compared to a group of healthy volunteers without hydrodynamic disorders. The study involved 35 subjects with communicating hydrocephalus (25 subjects with Evans index of 0.31; 10 subject with Evans index of 0.46) and 62 healthy volunteers. The mean, volume, and peak flow velocities were determined at the different intracranial levels. Also were made an assessment of gender and age differences. Analysis of the differences between the mean values showed the progressive inhibition of cerebrospinal fluid outflow from the cranial cavity [in moderate communicating hydrocephalus—at 1.5 times (p < 0.05), in severe communicating hydrocephalus at 2–2.5 times (p < 0.01)], depending on the severity of enlargement of the ventricular system and, most likely, related to inhibition of its reabsorption. These changes may explain the clinical symptoms of subjects and serve as diagnostic criteria. Also it was revealed a significant influence of the factor of age on speed characteristics of the cerebrospinal fluid flow (F = 5.3303, p = 0.0003, for mean velocity).

Poster: ECR 2015 / C-0424 / CSF flow quantification in patients with idiopathic intracranial hypertension (IHH) and hyperprolactinemia by data of phase contrast MRI by: O. Bogomyakova, N. Mesropyan, Y. Stankevich, L. Shraybman, A. Tulupov ; Novosibirsk/RU

Our study was designed to determine the effect of different forms of pathological tortuosity of the internal carotid arteries on the formation of hemodynamic flow profile. Using a 1.5 T magnetic resonance imaging (MRI) device, 50 healthy volunteers and 43 patients with pathological tortuosity of the internal carotid arteries were studied by applying routine MRI protocol and quantitative phase-contrast MR angiography. Changes in the peak, linear and volumetric blood flow rates as well as the cross-sectional areas of the vessel were measured during the cardiac cycle within the cervical and intracranial segments of the internal carotid arteries. 20 patients with pathological tortuosity of the internal carotid arteries were subjected to ultrasound study. In both, the control group and the group with pathological tortuosity, the shape of the curves that reflects the change in the linear blood flow rate as a function of the cardiac cycle, obtained with ultrasound and MRI, qualitatively coincides and does not depend on the tested segment of the artery and its path. The correlation coefficient was low between the peak blood flow rate obtained by ultrasound and MRI. The quantitative values of the blood flow rate, obtained in the control group and the group with pathological tortuosity, differed significantly in different segments of the internal carotid arteries. However, no significant differences were observed in blood flow rates between various forms of ICA tortuosity. The cross-sectional area was significantly higher in the case of pathological tortuosity of the internal carotid arteries as compared to the control group.

Poster: ECR 2015 / C-0535 / Asymmetry of cerebral venous outflow by: L. Savelyeva, Y. Stankevich, O. Bogomyakova, A. Tulupov ; Novosibirsk/RU

Poster: ECR 2014 / C-0345 / Method of functional magnetic resonance imaging in the evaluation of the effectiveness of the surgery of indirect revascularization of the brain. by: M. Rezakova, N. Nazarenko, Y. Stankevich, A. Savelov, A. Tulupov; Novosibirsk/RU

The purpose of this study is to characterize the cerebrospinal fluid (CSF) flow throughout the cardiac cycle in the conditions of Chiari I at intracranial and cervical levels. Magnetic resonance imaging studies were examined with phase-contrast magnetic resonance imaging retrospectively cardiac triggered (Quantitative Flow technique). 60 healthy volunteers (control group) and 12 patients with the anomaly of Chiari I (patient's group) were investigated. Mean velocity, mean flux and peak velocity values of CSF flow at the five levels (the Sylvian aqueduct, the fourth ventricle, the Magendie's foramen, subarachnoid space of the foramen occipital magnum and the cervical level) were defined. Analysis of differences between respective mean values of CSF flow has shown that CSF flow characteristics have the highest values in the Sylvian aqueduct and on the cervical level in both groups. Our findings show that mean velocity and mean flux of antegrade (from head to feet) flow have significantly higher values in comparison with the retrograde flow (from feet to head) through investigated structures, respectively (p < 0.01). Our findings show the importance of multi-level cerebrospinal fluid flow assessment and allow investigating this system as a single whole, with their relationships and interaction laws.

Poster: "ECR 2014 / C-1736 / Cerebral venous outflow in norm and in patients with cerebral venous thrombosis" by: "L. Savelyeva, Y. Stankevich, A. Tulupov; Novosibirsk/RU"

Poster: "ECR 2014 / C-0488 / CSF flow quantification in patients with communicating hydrocephalus using phase contrast MRI." by: "O. Bogomyakova, Y. Stankevich, L. Shraybman, A. Tulupov; Novosibirsk/RU"