Ultrasonic dopplerography of vessels of the neck and brain

Doppler( duplex scanning, ultrasonography) is a method of accurate, non-invasive, safe, painless and fairly quick assessment of carotid and vertebral arteries, venous system: hemodynamic parameters( velocity and blood flow disturbances) and vessel state( vascular wall lesions,state of vascular tone, atherosclerotic lesion).

The vascular system( arteries and veins) of the head .

Indications for carotid ultrasonography:

- transient ischemic attacks
- reversible neurological deficiencies, dizziness
- suffered strokes
- pulsating neck formation
- suspected vascular malformation
- hypertensive disease
- cerebral atherosclerosis
- visual disturbances
- osteochondrosis of the spine.

Dopplerography is performed: in the presence of headache, dizziness, impaired consciousness, with neurological symptoms.

How doppler is performed

Due to the fact that the carotid arteries are superficially located and easy to examine, they are a convenient window for assessing the condition of the arterial system as a whole. The development of atheroma is different in different vessels, but revealing early changes in carotid arteries makes it possible to suspect the defeat of other arteries.

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An early symptom of carotid artery involvement is an increase in the thickness of the intima-media. This indicator reveals a propensity to develop atherosclerosis. Earlier, the vascular wall in the bifurcation area of the common carotid artery is affected. The defeat of the endothelium of the vascular wall, the deposition of lipids, macrophages, the development of fibrosis leads to the formation of an atherosclerotic plaque. Depending on the composition of the plaque, they can be resistant, brittle, with erosions, with hemorrhages.

On erosive surfaces, thrombi can form, which have the ability to detach and enter the brain vessels. Plaques can increase due to the deposition of lipids and fibrous deposits, narrowing the lumen of the vessel and leading to stenosis. Distinguish hypoechoic with a thin rim, mostly hypoechoic with a small echogenic content inside, mostly echogenic with small hypoechoic areas, completely echogenic. It is believed that the first two types of plaques are often combined with clinical symptoms. Hypoechoic plaques are brittle, unstable. Echogenic plaques are fibrous and stable.

There are local and prolonged plaques - more than 1.5 cm. The plaque can occupy one side of the vessel, it can be concentric, semi-concentric. When the diameter of the vessel decreases, more energy is used to overcome stenosis, the pressure drops below the narrowed portion of the vessel. This reduces the perfusion pressure and worsens the blood supply to brain tissue. In the early stages this is compensated by an increase in speed, but with stenosis more than 50% of this is not enough. Stenosis of 50% is hemodynamically significant.

A - a small atherosclerotic plaque, the lumen of the vessel is somewhat narrowed, B- later stage - vessel stenosis, V-vessel occlusion, G-artery hyperplasia.

Doppler examination possible - extracranial and intracranial( transcranial) .

Scanning technique

The patient lies on the couch, on the back, his head is thrown back against the pillow.

The chin of the examinee is turned to the side opposite to the surveyed side. The study begins with a transverse scan of the lower segment of the common carotid artery to the right, tilting the sensor down to the upper mediastinum. Then the sensor is conducted up the neck around the corner of the jaws' jaws. This makes it possible to determine the depth and course of the carotid artery, the level of bifurcation, to determine the presence of atherosclerotic plaques. After this, include a color Doppler regime and treat the common carotid artery, bifurcation and each twig. The use of color makes it possible to quickly differentiate areas with disturbed blood flow and see anomalies of the vascular wall, plaques, thrombi. When an anomaly is detected, a thorough investigation is conducted to determine the severity of the lesion and its probable clinical significance. Further, the left carotid artery is also examined.

Next, vertebral arteries are examined. They can be seen in the vertebral canal, on the side of the vertebral bodies and between the transverse processes of the vertebrae. The sensor is located along the neck. The peak systolic velocity, the terminal diastolic velocity and the ratio of peak systolic velocities in the internal and common carotid arteries are of great importance in the study of blood flow, the determination of% stenosis.

Criteria for assessing the degree of carotid stenosis:

% stenosis in diameter Determination of stenosis	Peak systolic velocity	Peak diastolic velocity	Ratio
0%		rate 0.9	<0.5
0-15%	light	& lt; 1.1	& lt; 0.5
15 - 50%	moderate	& lt; 1.5	& lt; 0.5	& lt; 2
50-70%	heavy	& gt; 1.5	& lt; 0.5	& gt; 2
& gt; 70%	critical	& gt; 2.25	& gt; 0.75	& gt; 3
100%	occlusion	0	0

GSI B-mode to quantify the vessel diameter, the thickness of the layers of the vascular wall, the presence of intraluminal formations.

When examining in color Doppler mode, a color cartogram is assessed - homogeneity of filling the vessel, the presence of turbulence zones, uniformity of filling.

In the spectral Doppler mode, objective quantitative information is obtained on the nature of changes in the indices of local and systemic hemodynamics.

Investigation of veins is carried out in three modes - determine the permeability, geometry, diameter, condition of the vessel wall, luminal state, venous valves.

Transcranial duplex scanning of is performed through the scales of the temporal bone, through the large occipital opening, transorbital, through the scales of the occipital bone.

The posterior, middle and anterior cerebral arteries, the posterior connective artery, the main artery, the Rosenthal vein, the Galena, the straight line are visualized by placing the sensor anterior to the auricle( anterior temporal window) and above the auricle( middle temporal window) and posterior( posterior temporal window)sinus. Transorbital( the sensor on the closed upper eyelid) is visualized by the internal carotid siphon, the eye artery. Transoccipital and transtemporal positions are determined in the sitting position and visualize the intracranial separation of the vertebral arteries, the main artery, the cerebellar arteries, the direct sinus and the paravertebral and parabasillar venous plexuses. An obstacle to the study may be anomalies of the cervical spine, the absence of "ultrasonic windows" or their poor expression.

Deciphering the results of dopplerography

Ultrasound examination is carried out to identify pathology in the arterial and venous system and its evaluation - pathogenetic and hemodynamic significance, monitoring the effectiveness of treatment, the need for angiography and referral to angio-surgery for solving the issue of surgical treatment.

Identified lesions:

- organic changes with objective ultrasound signs - stenosing atherosclerosis, aneurysms, arteriovenous malformations, thrombosis, varicose veins,
- processes that do not have a specific ultrasound pattern - non-stenotic atherosclerosis, angiopathy, vasculitis.

With non-stenosing atherosclerosis , violations in the structure of intima-media complex of large arteries, uneven changes in echogenicity, pathological thickening of the vessel wall with a narrowing of the lumen of no more than 20% are revealed. Normally, the thickness of the vascular wall is considered to be 0.9, the borderline values are 0.9-1.1.

With stenosing atherosclerosis , atherosclerotic plaques are determined. Structural features of plaques are important for assessing the potential ability to be the source of embolism.

With vasculitis , the ultrasound pattern depends on the stage of the pathological process - diffuse changes in the vascular wall, disturbance of the differentiation of the layers, decreased or increased echogenicity, signs of the inflammatory process.

With , the temporal arteritis of in the superficial temporal artery and its branches shows a diffuse uniform wall thickening with low echogenicity.

With , the long-term course of the inflammatory process of is joined by the symptoms of atherosclerotic lesion.

When diabetes mellitus , signs of macro and microangiopathies are revealed.

Arteriovenous malformations of are a pathological vasculature of various diameters or arteriovenous fistula, or a network of vessels with a diameter of more than 200 μm. Absorbing veins are sharply hypertrophied with hyalinosis, calcification, liposome infiltration. Thinning of the vascular wall can lead to hemorrhages. The development of the syndrome of arteriovenous shunting leads to an intracerebral syndrome of "stealing" and a violation of cerebral circulation.

The most common abnormality of the vertebral arteries is hypoplasia .This reduces its diameter to 2mm or less. Depending on the severity of hypoplasia and its hemodynamic significance, there will be ultrasonic signs. Often an anomaly of the vertebral artery enters the canal of the transverse processes of the cervical vertebrae. As a rule, this anomaly does not affect hemodynamics.

Anomalies in the structure of the connecting arteries of the Willis circle can be determined.

With ultrasound examination, it is possible to determine extravasal compression - compression of the vessel wall from the outside, sprouting into the vessel wall. At the cervical level, the frequent cause of vasoconstriction is the pathology of the thyroid gland, enlarged lymph nodes, osteophytes of the cervical region can squeeze the vertebral arteries. Ex-arausal compression may be caused by a tumor process. All these findings will require additional examination.

Doctor neurologist Kobzeva S.V.