Neurosonography

Neurosonography, an ultrasound diagnostics section that studies brain in newborns, is now an integral part of traditional neonatology and perinatal neurology, without which no examination of a child neurologist and / or neonatologist can do. The technique is harmless, it can be applied many times, it allows to assess the structure of the brain, the state of the cerebrospinal fluid pathways and to identify various pathological changes (hemorrhages and ischemic lesions, congenital developmental anomalies, changes in the brain during infection). Neurosonography makes it possible to determine the morphological substrate of neurological disorders arising in the perinatal period and radically changed the opinion of neurologists on the incidence of vascular brain pathology in newborns. Often, with a normal ultrasound picture of the brain, there is a pronounced neurological symptoms, which are based on cerebral circulation disorders. It is noted that 40-60% of children have neurological disorders of vascular genesis.

Cerebral injuries in newborns are often not only the cause of the development of critical conditions in the early neonatal period and the formation of various syndromes of perinatal encephalopathy (PEP), but also often determine the life prognosis. In pediatric neurology, it has traditionally been believed that brain lesions of vascular genesis are extremely rare. However, in recent years, the introduction of ultrasound methods into clinical practice has shown that the origins of adult vascular pathology often lie in childhood, and many of them are 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 due to perinatal factors.

Early nosological diagnosis of brain lesions in newborns is difficult due to 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, today there are: hypoxic-ischemic disorders, intracranial hemorrhages and toxic-infectious lesions. Ischemia of the brain 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 the blood flow in the vessels of the brain, since its disorders are the main cause of perinatal hemorrhagic-ischemic brain lesions.

Neurosonography in newborns is carried out in a maternity hospital, in the departments of pathology of newborns and nursing of premature babies, while using portable devices. Brain scans in children who are in serious condition (in the intensive care or resuscitation ward) are carried out in incubators. The severity of the condition is not a contraindication for neurosonography. Special medication preparation and anesthesia is 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 sanitary conditions). Screening ultrasound should be carried out for each child at discharge from the maternity hospital, then it is repeated at 1 month of life, when the child is first brought to the pediatric clinic for an appointment with a pediatrician, a children's neurologist. The following neurosonography is performed according to indications depending on the clinical symptoms or to assess the dynamics of treatment.

For neurosonography in newborns and young children, ultrasonic devices operating in real time, sensors with a scanning frequency of 3.5 to 14 MHz are used. For newborns and children up to three months of life, the 7.5 MHz sensor is optimal, between the ages of 3 months and older - 3.5-5 MHz, after 9 months, when the large spring is covered with 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. Triplex scanning mode in real time is optimal, because it allows the researcher, regardless of the emotional state of the child, to obtain the necessary information on the monitor screen of an ultrasonic device in a short time period.

Indications for neurosonographic research are:

1. Hydrocephalus (enlarged 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 carried out through a large (anterior) fontanelle, on which an ultrasonic sensor is placed to obtain images in the frontal (coronary), sagittal and parasagittal planes. When the sensor is positioned strictly along the coronary suture, cross sections are obtained in the frontal plane, then, turning the sensor 90 °, cross sections are displayed in the sagittal and parasagittal planes. By changing the tilt of the sensor forwards, backwards, to the right and left, a series of sections are successively obtained to evaluate the structures of the right and left hemispheres.

Method of neurosonography 

[1], [2], [3], [4]

Technology Doppler study of the brain in children

Currently, in neonatology, duplex Doppler systems are used, which allow us to visualize a vessel in an ultrasound section of the brain, establish a control volume in its lumen, and obtain a Dopplergram, which reflects the blood flow in this vessel. Ultrasonic devices with color (energy) Doppler mapping (DDC) allow you to choose the optimal position for placement of the control volume in the large cerebral arteries to measure the speed with minimal error, as well as to obtain 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, cerebral hemodynamic disorders in the form of hemorrhagic and ischemic changes occupy a significant place, which in frequency and localization depend on the severity of the morphofunctional immaturity of the central nervous system and the imperfection of autoregulatory mechanisms of cerebral blood flow. Hemorrhagic and ischemic brain lesions can be observed in various combinations.

 Ultrasound signs of vascular disorders 

Changes in hemodynamics of the brain associated with the growth and development of the child

Indicators of cerebral blood flow in a healthy newborn are determined primarily by gestational age and the presence (or absence) of a hemodynamically significant functioning arterial duct. The persistence of the latter is accompanied by the discharge of blood into the pulmonary circulation with depletion of blood flow in the vessels of the brain, which is characterized by a 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, there is a gradual increase in BFV indices, a decrease in PI and IR in arteries and an increase in average velocity in large venous reservoirs. 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 resistance of the cerebral vessels.

 Changes in brain hemodynamics and child growth 

[5], [6], [7], [8], [9], [10], [11]

Hemodynamics of the brain in perinatal lesions 

For newborns with hypoxic-ischemic brain damage (cerebral ischemia) I-II severity is generally characterized by the same patterns in changes in cerebral hemodynamics, as for healthy newborns, but at lower linear blood flow rates (mostly diastolic). From 3 days of life, no significant differences in linear cerebral blood flow rates in healthy newborns and children with grade II ischemia were noted, which reflected the reversibility of the revealed disorders, their “functional” nature.

 Hemodynamics of the brain and perinatal brain damage

[12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22]