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Nazarova Janna, scientific applicant Tashkent Postgraduate Medical Institute E-mail: nilu74@list.ru
CEREBRAL HEMODYNAMICS IN PATIENTS WITH CEREBRAL VENOUS DYSFUNCTION
Abstract. The experience of using different methods of magnetic resonance study of the arterial and venous parts of the vascular bed of the head and neck is analyzed, and the feasibility and possibility of simultaneous assessment of the state of the brain and the study of the anatomy of the cerebral bed are shown.
Keywords: chronic cerebrovascular accident, venous hemodynamics, magnetic resonance imaging, duplex scanning.
Disorders of cerebral circulation in arterial hyperonia (AH) are one of the most pressing problems of modern cardiology and neurology, remaining the subject of discussion to date. It is known that disorders of the venous circulation play an important role in the reactions of cerebral autoregulation [8; 10].
Thus, with increasing blood pressure, there is an increase in the diameter of the veins and an increase in the permeability of the blood-brain barrier [9; 11]. According to many authors, when using magnetic resonance imaging (MRI) techniques focused on the study of the venous bed, patients with hypertension revealed the following changes: expansion of the superficial cerebral veins, lack of a signal from the blood flow or reduction in the size of the transverse and sigmoid sinus, combined with expansion of the sizes of the sinuses of the same name from the opposite side etc. [1; 4; 7]. Further research in this direction may allow developing new approaches to the prevention and treatment of hypertensive encephalopathy.
The advantages of MRI are not limited to the visualization of anatomical structures. Functional MRI created on the basis of angiographic techniques allows to evaluate the change in the velocity of the venous flow. This compares the change in the intensity of the signal on the angiograms obtained at rest and under conditions leading to the activation of a specific department or region of the cerebral cortex [4; 7].
Interest in studying the characteristics of the cerebral venous circulation and attempts to assess its significance in the violation of cerebral circulation are determined, on the one hand, by the existing trend of increasing the number of patients suffering from vascular diseases, on the other hand, by the active development and implementation of modern visualization technologies [2; 3; 5; 6].
In the available specialized literature, we were not able to find systematic data on the value of magnetic resonance angiography in assessing the arterial and venous circulation of the brain, which served as the basis for conducting this study.
Purpose of the study. Justify the possibility of conducting and determine the features of the magnetic resonance venography in violation of cerebral arterial blood flow.
Materials and methods. In 87 patients with chronic cerebral ischemia (CCI) on the background of hypertension were examined, of whom 36 were women and 51 men aged from 46 to 72 years old (mean age 57.2 ± 11.3 years). The patients were divided into 2 groups: CBI Stage I - 33 patients, CBI II - 54. In the examined patients, the mean systolic blood pressure was 181. 7 ± 9.3 mm Hg. Art., average diastolic - 112.3 ± 17.6 mm hg. art. The average duration of hypertension was 9.2 ± 8.2 years (0.7-25 year). The control group consisted of 20 healthy individuals aged from 36 to 64 years old (mean age 49.1 ± 9.7 years).
All patients underwent standard neurological examination, brain MRI with venography (MRV) of the brachiocephalic veins and venous sinuses of the brain, duplex scanning (DS) in the modes of color Doppler mapping and pulsed Doppler of extra- and intra-cranial vessels.
MRI and MRI were performed on a Magnetom Verio 3 T and Magnetom Avanto 1.5 T from Siemens according to a generally accepted method. Brain scans were performed in axial, sagittal and coronary projections with slice thickness from 4 mm with T1 - TR programs - 450 ms, T2 - TR - 6000 ms, tirm TR - 600 ms, TI - 110 ms, contrast enhancement occurred upon injection of10-20 ml of a 5% magnneist solution (Schering). For MPA and MRI, a two-dimensional time-of-flight angiography (2DTOF) technique was used. Using fast T2-weighted programs, we evaluated the state of cerebrospinal fluid dynamics in sylvium aqueduct. To assess the CSF dynamics, the intensity of the signal from the pulsation of the cerebrospinal fluid in the sylvian aqueduct was compared with the intensity of the signal in the lateral ventricles at the same level.
Results and discussion. All patients complained of dull headaches, more pronounced in the morning. The pains were mostly of a diffuse nature, occipital localization and in most cases combined with pain in the neck. In 49(36%) patients, headaches were accompanied by a moderately pronounced "noise in the head".
32(36.8%) patients complained of pain in the cervical spine. Pain syndrome was more often characterized as chronic with periodic exacerbations. They noted the frequent connection of cervicalgia with headaches, a little less - with dizziness.
CEREBRAL HEMODYNAMICS IN PATIENTS WITH CEREBRAL VENOUS DYSFUNCTION
Along with the headache, the subjects noted difficulty
concentrating, absent-mindedness. 61(70.1%) patients complained of sleep disturbance (superficial sleep, headaches on waking, a decrease in the level of daytime wakefulness) and dizziness. Dizziness were mostly non-systemic in nature, there was instability when walking, incoordination, which are especially clear when performing small movements.
During neurological examination, vestibulo-atactic disorders in the form of instability during walking, staggering in the Romberg position, elements of dysmetry, indistinctness when performing knee-heel and paltse- nose test tests were most often encountered. The deficiency of oculomotor innervation, consisting in the weakening of convergence and accommodation, was noted less often. Visual disturbances in the form of cattle-resistant, photopsies were also observed. Signs of pyramidal insufficiency manifested in the form of asymmetry of tendon and periosteal reflexes, pathological foot and hand symptoms.
DS and MRA revealed in patients the presence of occlusive processes in the form of tortuosity and stenosis. In chronic cerebral ischemia, grade 1, crimpiness occurred in 31.4%; with chronic cerebral ischemia 1 degree II Art.- in 38.2% of patients. Thus, the tortuosity of the carotid arteries was characteristic of all hypertensive patients, regardless of the stage of CBI. No statistically significant difference between the parties was obtained (p> 0.5).
Atherosclerotic changes were detected in 27% of patients. Atherosclerotic changes were detected in 27% of patients. At the same time, a seal of the arterial wall was noted, atherosclerotic plaques were detected, loosening and an increase in the intima of the vessels. The spread of indicators of the intima-media complex was significant and ranged from 0.6 to 2.7 mm with an average of1.4 ± 0.4.
With CBI there was only a tendency to a decrease in the volumetric blood flow velocity against the background of a moderate decrease in the blood flow velocity in the posterior circulation arteries. At stage II of the disease, there was a decrease in the linear and volumetric blood flow rates in the ICA. In the arteries of the posterior circulation revealed a significant decrease in blood flow velocity. As for the DE III, there was a pronounced decrease in the linear and volumetric blood flow velocity, especially in the arteries supplying the back sections of the brain.
Taking into account the role of the common jugular vein as a collector of venous outflow from the cranial cavity, we analyzed the indicators ofblood flow in it at different stages of CBI.
In all patients with CIM, the lumen of the internal jugular veins (IJA) was free. A valve was visualized in all cases at the mouth of the IJA. In most cases, a bicuspid valve was detected.
To assess the viability of the IJA valvular apparatus, a respiratory load test was performed: in response to a deep
breath, closing of the valve leaflets was observed, accompanied by a significant reduction in blood flow to the IJA. In 59(67.8%) cases with functional test, reversal of blood flow in valvular insufficiency was noted. No cases ofvalvular insufficiency were detected in the control group.
In all patients examined in the control group and in the majority of patients with CBI, the blood flow in the IJA had a three- or four-phase character, synchronized with the act of breathing. In 1/3 of the cases, low-amplitude flow with reduced phasing was noted.
The study of the vertebral veins was performed in the supine position, and the flow of the PT was determined in patients with CBI, Stage I, in 26.4% of cases. CBI II Art.- 42.7%. When switching to orthostasis, in 100.0% of cases in both groups. The failure of visualization of the vertebral veins was associated with the quality of visualization in general. Thus, more often, vertebral veins was untenable in patients with CBI II (p < 0.05).
Comparative assessment of brain MRI results in patients with CBI revealed diffuse changes in the signal intensity from the white matter of the brain (periventricular, subcortical leucoarea, LA), single or multiple ischemic foci of 115 mm, external and internal cerebral atrophy (CA). Large ischemic foci (cortical and subcortical heart attacks) in the examined patients were absent. Patients with CBI II differed more pronounced periventricular LA of all localizations compared with the group of patients with CBI II (p < 0.05); symmetry of atrophic changes in the brain (the absence of significant differences in the index of the bodies of the lateral ventricles - ITBJ, the linear dimensions of the anterior horns and the bodies of the lateral ventricles on the right and left); the prevalence of single and small (up to 5 mm) ischemic foci in the brain substance (43.4% with 10.7% CBI II, p < 0.05). Compared to patients with CBI I, patients with CBI II were characterized by a greater (p < 0.05-0.01) severity of asymmetric internal cerebral atrophy with predominant left hemisphere involvement (average values of ITBI, linear dimensions of the anterior horns and bodies of the lateral ventricles significantly higher left than right); a high representation of multiple ischemic foci with a size of > 5 mm in the brain substance (39.3% with 10.4%, CBI II, p < 0.01), especially in the deep sections of the white matter of the frontal lobes (50% and 23.1 respec-tively%), the head of the caudate nucleus (60.7% and 33.3%), the thalamus (60.7% and 30.8%) and the brain bridge (46.0% and 20.5%), i.e. in structures that are functionally significant for developed KP [11].
According to MRI, the majority of patients were identified asymmetry of the main venous reservoirs; jugular veins and cerebral sinuses mainly on the right side were enlarged in 53% of patients, on the left side - in 27%. Analysis of the
MRI data showed that in 58% of cases an abnormal development of the drainage system of the brain was detected. Thus, in 36% of cases, hypoplasia of one of the transverse sinuses was diagnosed (12 in the left, 6 in the right), and 14% of the patients showed aplasia in the transverse sinus. In 6 cases revealed hypoplasia of the sigmoid sinuses (right - 4, left - 2). In all cases, abnormalities in the development of the venous sinuses noted a compensatory expansion of the lateral sinus, and in some cases, the upper and lower stony sinuses were visualized, and their detection is normally difficult.
Thus, in chronic cerebrovascular disease, along with changes in the arterial blood flow, changes in the regulation
of the venous circulation are indicative. In chronic cerebral ischemia, both a comparative expansion of the VNV and a relative decrease in the intensity of blood flow in them is noted.
Based on the conducted research, the feasibility and the possibility of a one-stage assessment of the state of the brain and the study of the anatomy of the cerebral bed are substantiated. The need for an extended magnetic resonance study of the vascular system in the lesion of the arterial bed of the brain is due to certain anatomical and functional relationships between the arterial and venous sections.
References:
1.
Ejova O.B., Tulupov A. A. Opportunities for magnetic resonance imaging in evaluating liquorodynamics and venous outflow from the brain // Scientific Conference "Medical Genomics and Proteomics".- Novosibirsk. 2009.- 172 p. Semenov S. E. Duplex color scanning and transcranial dopplerography for obstructive disorders of cerebral venous circulation // Ultrasound Doppler diagnostics in the clinic / IIC, 2004.- P. 5215-240.
Pushkina L. I., Bekuzarova M. I., Kamchatnov P. M. and etc. Cerebral and central hemodynamics in patients with severe forms of cerebral circulation insufficiency // Neurodiagnostics. 2003.- No. 4.- P. 53-56.
Kamchatnov P. R. Chronic cerebral blood circulation disorders in patients with arterial hypertension // Clinician. 2006.-No. 2.- P. 14-22.
Kuntsevich G. I., Dan V. N., Timina I. E., Burtseva E. A. Evaluation of venous hemodynamics in patients with occlusive lesions of the major arteries of the neck according to ultrasound // Ultrasound. and function. Diagn. 2002.- No. 4.-P. 60-65.
Lelyuk V. G., Lelyuk S. E. Cerebral blood circulation and blood pressure // - M.: "Real Time", 2004.- 304 p. Savelieva L. A., Tulupov A. A. Features of the venous outflow from the brain according to magnetic resonance angiography // Vestnik NGU. 2009.- T. 7.- Issue 1.- P. 36-40.
Shmyrev V. I. Cerebrovascular disorders in elderly patients with arterial hypertension / V. I. Shmyrev T. A. Bobrova // Clinical gerontolgy. 2001.- No. 10.- P. 7-10.
Skvortsova V. I. et al. Chronic brain ischemia // Diseases of the heart and blood vessels. 2006.- V 1.- No. 3.- 43 p.
10. Tulupov A. A. The possibilities of MRI in the quantitative assessment of cerebral venous blood flow in normal and thrombotic lesions // Bulletin NTSSSH them. A. N. Bakuleva RAMS "Cardiovascular diseases". 2011.- T. 12.- No. 3.-P. 66-73.
11. Yakhno H. N. Comparison of clinical and MRI data for dyscirculatory encephalopathy / H. N. Yakhno, O. S. Levin, I. V. Damulin // Neurological Journal. 2001.- V. 6.- No. 3.- P. 10-19.
2.
3.
4.
5.
9.
