Ultrasonic dopplerography of the venous system

Acoustic signals from the arteries and veins are markedly different: if the first have a pulsating high tone, synchronous with cardiac contractions, then the venous noise is characterized by a low unmodulated sound resembling the sea surf and varies in intensity depending on the stage of the respiratory cycle. Graphic registration of phlebodipleropharm on conventional devices is not possible due to low signal strength and imperfection of inertial systems of recorders. Spectrographic analysis allows you to clearly record the venous stream.

• When studying the circulation of the orbital vein, the subject lies on his back with his eyes closed, his head on a small cushion. The gel is applied to the inner corner of the eye. The ultrasonic sensor is installed in the place of applying the gel at an angle of 10% to the projection of the sagittal sinus and at an angle of 20% to the coronary suture. By the small rocking of the probe with very weak pressure on the eyeball, a search and recognition of the signal from the orbital vein is carried out. The location, as a rule, is facilitated by the preliminary determination of the signal from the supraclavicular artery, in the immediate vicinity of which the sought-for vein is usually located. The same procedure is performed in a symmetrical region from the opposite side. The pressure of the probe should be minimal (weaker than with the location of the orbital artery) to avoid compression of the vein, which is manifested by the disappearance of the blowing signal.
• The signal from the jugular veins is easiest to get in the lower third of the neck, slightly anterior to the lateral surface of the sternocleidomastoid muscle in the region of the supraclavicular triangle. The search for and recognition of the signal from the jugular vein is easier to carry out after receiving a pulsating signal from the common carotid artery: a small displacement of the sensor from the outside with decreasing pressure on the skin most often makes it possible to fix a characteristic blowing signal having the opposite direction from the common carotid artery - from the cranial cavity downwards from the isoline.
• Determining the signal from the subclavian vein usually does not cause difficulties. The location of the subclavian vein allows to conduct its unmistakable puncture (for the introduction of a venous catheter and subsequent infusion therapy). This is especially important in cases of anatomical and physiological features in the neck of the patient. First, by placing the sensor 0.5 cm below the clavicle in its outer third, a pulsating signal from the subclavian artery is identified. Then, by a small change in the angle of inclination and the degree of compression, a characteristic blowing noise of the subclavian vein is found. They find such an arrangement and degree of pressing of the sensor, at which the signal from the subclavian vein is maximal - it is at this place and at this angle that a needle is inserted for catheterization of the subclavian vein.
• The signal from the veins of the vertebral plexus is located approximately in the same zone as the flow signal from the vertebral artery, a little lower and medial to the mastoid process.

The most important aspect of the semiology of venous cerebral circulation is the evaluation of blood flow through the orbital veins. In healthy people, blood from the deep and superficial veins of the face over the maxillary vein goes to the medial edge of the orbit and through the orbital vein enters the cavernous sinus. In the cavernous sinus passes the internal carotid artery - it is located in the center of the venous lacuna, the wall of which is attached to the adventitial membrane of the artery. The walls of the venous sinus are fixed and unyielding, so the change in the caliber of the internal carotid artery during its pulsation in the lumen of the sinus changes its volume, which stimulates the outflow of venous blood. Normally, a much more powerful flow signal through the orbit artery in the orthograde direction from the cranial cavity completely or partially suppresses a much weaker venous signal, which also has the opposite direction (to the cavernous sinus). Therefore, in most healthy people with periorbital ultrasound dopplerography, only the arterial flow from supratrochlear and supraorbital vessels is recorded in the absence of a venous component.

Nonphysiological venous outflow from the cranial cavity has the following features:

• symmetrical or asymmetric signal from the orbital veins of moderate intensity;
• amplified signal when locating the vertebral plexus zone in a lying patient, i.e. Outflow occurs both in the jugular veins and in the vertebral plexus.

It should be borne in mind that similar variants of phlebocirculation can be present both in practically healthy people and in patients with various conditions, somehow including a component of vegetative-vascular dystonia by venous type. In addition, if the asymmetry of the linear velocity of the blood flow is detected for the first time in the cerebral arteries and at subsequent examinations, the signs of venous discirculation are very variable and depend on a number of factors, primarily positional ones. This is particularly evident in the clinical and instrumental tracking of patients with signs of venous encephalopathy, manifested in the morning hours. As some studies have shown with monitoring by ultrasound dopplerography before and after sleep, signs of mild or severe venous circulation in the form of an unphysiological redistribution of outflow and / or an apparent retrograde flow through the orbital veins are present in the vast majority of patients if repeated ultrasound dopplerography is performed in bed before transition of the awakened patient to a vertical position. It turned out that it was at this time that clinical manifestations (headache, ringing, tinnitus, edema under the eyes, nausea) and ultrasound dopplerography patterns (sharp venous dyskirkulyatsiya in the orbit and / or vertebral veins) occur. After 5-10 minutes after lifting and hygienic procedures, the patients feel well in parallel with a clear decrease in the signs of venous circulation.

If the above patterns of moderate venous disgamy are variable and variable, then there are a number of pathological conditions in which signs of venous outflow disturbances are pronounced and persistent. These are focal lesions of the brain, especially with localization in the anterior and middle cranial fossa, and traumatic subdural hematoma. In the triad of ultrasound signs of this pathology, in addition to the displacement of the median structures and the hematoma echo, the symptom of a sharp increase in the retrograde flow through the eye vein on the side of the clusters of blood accumulates for the first time. The account of these patterns allows in 96% of cases to establish the presence, side of the lesion and the approximate volume of subdural hematoma.

A sufficiently pronounced lateralized retrograde flow through the ophthalmic vein is also noted in otogenic and rhinogenic abscesses, hemispheric tumors of parietal-temporal localization.