Neurosonography

Neurosonography is a section of ultrasound diagnostics that studies the brain of newborns. It is currently an integral part of traditional examination in neonatology and perinatal neurology, without which no examination by a pediatric neurologist and/or neonatologist can do. The technique is harmless, can be used repeatedly, allows you to assess the structure of the brain, the state of the cerebrospinal fluid pathways and identify various pathological changes (hemorrhages and ischemic lesions, congenital anomalies, changes in the brain during infection). Neurosonography allows you to determine the morphological substrate of neurological disorders that occur in the perinatal period and has radically changed the opinion of neurologists about the frequency of vascular pathology of the brain in newborns. Often, with a normal ultrasound picture of the brain, there is pronounced neurological symptoms, which are based on cerebrovascular disorders. It is noted that 40-60% of children have neurological disorders of vascular genesis.

Cerebral damage in newborns is often not only the cause of critical conditions in the early neonatal period and the formation of various syndromes of perinatal encephalopathy (PEP), but also often determines the life prognosis. In pediatric neurology, it was traditionally believed that brain damage of vascular genesis is extremely rare. However, in recent years, the introduction of ultrasound research methods into clinical practice has shown that the origins of vascular pathology in adults often lie in childhood, and many of them in the perinatal period. According to modern data, up to 70-80% of diseases of the nervous system leading to disability and maladaptation of children are caused by perinatal factors.

Early nosological diagnostics of brain damage in newborns is complicated by the similarity of clinical neurological manifestations in various pathological conditions, which is associated with the anatomical and functional immaturity of the nervous system and the nonspecific response of the brain to various intrauterine pathological processes. Among the cerebral lesions that cause the development of perinatal encephalopathy in children of the first year of life, the following are currently distinguished: hypoxic-ischemic disorders, intracranial hemorrhages and toxic-infectious lesions. Cerebral ischemia and intracranial hemorrhages can be combined, and infectious lesions can be accompanied by both hemorrhages and ischemia.

The use of the Doppler effect made it possible to conduct a non-invasive study of blood flow in the vessels of the brain, since its disturbances are the main cause of perinatal hemorrhagic-ischemic brain damage.

Neurosonography of newborns is performed in the maternity hospital, in the neonatal pathology department and the premature infant care department, using portable devices. Brain scanning of children in serious condition (in the intensive care unit or resuscitation unit) is performed in incubators. The severity of the condition is not a contraindication for neurosonography. Special drug preparation and anesthesia are not required. If the doctor has only a stationary scanner in the children's clinic, the examination takes place at the appointed time in the ultrasound examination room, in the maternity hospital only after special sanitary treatment of the room and the device (according to the sanitary and epidemiological regime). Screening ultrasound examination must be performed for each child upon discharge from the maternity hospital, then it is repeated at 1 month of life, when the child is first brought to the children's clinic for an appointment with a pediatrician, child neurologist. The following neurosonography is performed according to indications depending on clinical symptoms or to assess the dynamics of treatment.

To perform neurosonography in newborns and young children, ultrasound devices operating in real time are used, sensors with a scanning frequency of 3.5 to 14 MHz. For newborns and children up to three months of life, a 7.5 MHz sensor is optimal, at the age of 3 months and older - 3.5-5 MHz, after 9 months, when the large fontanel is covered by a membranous structure and / or completely closed - 2-3.5 MHz. When using linear sensors of 7.5-10 MHz, a detailed assessment of the anterior sections of the subarachnoid space is possible. The triplex scanning mode in real time is optimal, since it allows the researcher, regardless of the emotional state of the child, to obtain the necessary information on the monitor screen of the ultrasound device in a short period of time.

Indications for neurosonographic examination are:

1. Hydrocephalus (enlargement of the head).
2. Intracranial hematoma.
3. Brain damage due to hypoxemia.
4. Meningocele and other congenital anomalies.
5. Convulsive syndrome.

Indications for neurosonography

Neurosonography technique

Standard neurosonography is performed through the large (anterior) fontanelle, on which an ultrasound sensor is placed to obtain images in the frontal (coronary), sagittal and parasagittal planes. When the sensor is positioned strictly along the coronary suture, sections are obtained in the frontal plane, then, by turning the sensor by 90°, sections are obtained in the sagittal and parasagittal planes. By changing the tilt of the sensor forward - backward, right - left, a series of sections are sequentially obtained to assess the structures of the right and left hemispheres.

Methodology for conducting neurosonography

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Doppler technology for brain examination in children

Currently, neonatology uses duplex Doppler systems that allow visualizing a vessel in an ultrasound section of the brain, installing a control volume in its lumen, and obtaining a Dopplerogram reflecting the blood flow in this vessel. Ultrasound devices with color (power) Doppler mapping (CDM) allow choosing the optimal position for placing the control volume in large cerebral arteries to measure velocity with minimal error, as well as obtaining an image of the venous vessels of the brain.

Dopplerography of the brain in children

Ultrasound semiotics of vascular disorders

Among neurological pathologies in newborns, a significant place is occupied by disorders of cerebral hemodynamics in the form of hemorrhagic and ischemic changes, which in frequency and localization depend on the severity of the morphofunctional immaturity of the central nervous system and the imperfection of the mechanisms of autoregulation of cerebral blood flow. Hemorrhagic and ischemic lesions of the brain can be observed in different combinations.

Ultrasound signs of vascular disorders

Changes in brain hemodynamics associated with child growth and development

The cerebral blood flow parameters of a healthy newborn are determined primarily by the gestational age and the presence (or absence) of a hemodynamically significant functioning ductus arteriosus. The persistence of the latter is accompanied by a blood discharge into the pulmonary circulation with depletion of blood flow in the cerebral vessels, which is characterized by low diastolic velocity, and sometimes a change in systolic velocity. Normally, with an increase in gestational, postnatal age and weight during the first months of life, a gradual increase in LBFV parameters, a decrease in IP and IR in the arteries and an increase in the average velocity in large venous collectors are noted. The greatest changes occur on the first 2-4 days of life, which is associated with the closure of fetal communications and a gradual decrease in the resistance of the cerebral vessels.

Changes in brain hemodynamics and child growth

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Hemodynamics of the brain in perinatal lesions

Newborns with hypoxic-ischemic brain damage (cerebral ischemia) of I-II severity are generally characterized by the same patterns in changes in cerebral hemodynamics as healthy newborns, but with lower linear blood flow velocities (diastolic to a greater extent). From the 3rd day of life, no reliable differences in the linear velocities of cerebral blood flow were noted in healthy newborns and children with ischemia of II severity, which reflected the reversibility of the detected disorders, their "functional" nature.

Brain hemodynamics and perinatal brain damage

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