Structural changes in the brain during hypoxic-ischemic damage to the central nervous system in newborns of different gestational ages. Comparison of echographic picture with data

Index of the central parts of the lateral ventricles

The index of the central sections of the lateral ventricles is calculated by the ratio of the smallest distance between their outer walls in the area of ​​the recess to the maximum internal diameter of the skull on the same section, multiplied by 100. Normally, the value of this index ranges from 18.2 to 26.0 [1].

Index of the central parts of the lateral ventricles ICVBI = C/Dx100 [1]

Fig.1 Measurement of the lateral ventricle index

III ventricle index

The index of the third ventricle is assessed by the ratio of its maximum width in the posterior third at the level of the pineal body to the largest transverse diameter of the skull on the same section, multiplied by 100. Normally, the value of this index increases with age, being equal to 3.0 at the age of up to 5 years and 4 .8 – from 71 to 80 years [1].

III ventricle index = E/Fx100 [1]

The Schlatenbrandt-Nurenberger index (third ventricle index) is the ratio of the maximum transverse diameter of the skull (F) and the width of the third ventricle (E) [2]. A value from 30 to 50 is considered a normal value; a value less than 20 indicates a mild degree of hydrocephalus [2].

Common diseases of the third ventricle of the brain

Most often, the problem of impaired outflow of cerebrospinal fluid occurs in children - newborns and babies up to one year old. One of the most common diseases at this age is ICH (intracranial hypertension) and its complication – hydrocephalus.

During pregnancy, the expectant mother undergoes mandatory ultrasound examinations of the fetus, which make it possible to identify congenital malformations of the child’s central nervous system in the early stages. If during the examination the doctor notes that the 3rd ventricle of the brain is dilated, additional diagnostic tests and careful medical supervision will be needed.

If the cavity of the 3rd ventricle in the fetus becomes more and more dilated, in the future such a baby may require bypass surgery to restore the normal outflow of cerebrospinal fluid.

Also, all born babies at two months of age (earlier if indicated) undergo a mandatory medical examination by a neurologist, who may suspect dilation of the 3rd ventricle and the presence of ICH. Such children are sent for a special examination of brain structures - NSG (neurosonogathia).

What is NSG?

Neurosonography is a special type of ultrasound examination of the brain. It can be performed on infants because they have a small physiological opening in the skull - the fontanel.

Using a special sensor, the doctor receives an image of all the internal structures of the brain, determines their size and location. If the 3rd ventricle is dilated in the NSG, more detailed tests are performed - computed tomography (CT) or magnetic resonance imaging (MRI) to obtain a more accurate picture of the disease and confirm the diagnosis.

IV ventricle index

The index of the fourth ventricle is calculated by the ratio of its greatest width to the maximum internal diameter of the posterior fossa of the skull on the same section. Normal values ​​for this index are 11.9-14.0. The size of the ventricular system does not depend on gender [1].

IV ventricle index = H/Ix100 [1]

Fig.2 Measurement of indices of the third and fourth ventricles

The Akimov-Komissarenko index is usually used for moderate or slight deformation of the ventricles of the brain. It is determined by calculating the total cranioventricular coefficient using the formula

4d/(a+b+c+c1), where

• d is the transverse diameter of the skull,
• a - the distance between the outer walls of the anterior horns of the lateral ventricles,
• b – width of the anterior sections of the anterior horns,
• c — distance from the superior internal angle to the outer wall of the right lateral ventricle,
• c1 — the same distance of the left ventricle.

A value of more than 5.2 is normal, from 5.2 to 4.8 indicates an insignificant degree of hydrocephalus, from 4.8 to 4.4 - moderate and less than 4.4 - severe hydrocephalus [2].

Diagnostic methods

For the first time, a doctor can pay attention to deviations in the size of brain structures from the norm during an intrauterine ultrasound examination of the fetus. If the head size does not return to normal, a repeat ultrasound is performed after the baby is born.

Enlargement of the ventricles of the brain in newborns is diagnosed after neurosonography - ultrasound performed through the skin of an undeveloped fontanel. This study can be carried out until the child’s skull bones have completely fused.

If the disease develops chronically, the doctor may pay attention to the fact that the ventricles of the brain are larger than normal when examining the child with an ultrasound scan at three months of age. To clarify the diagnosis, it is recommended to undergo additional examination:

• Ophthalmological examination - helps to identify swelling of the eye discs, indicating increased intracranial pressure, hydrocephalus.
• Magnetic resonance imaging can be used to monitor the growth of the cerebral ventricles after the bones of the child’s skull have fused. MRI is a long procedure, the time spent under the machine is 20-40 minutes. In order for the child to lie motionless for such a long time, he is immersed in medicated sleep.
• When undergoing a CT scan, you do not need to remain motionless for a long time. Therefore, this type of study is suitable for children for whom anesthesia is contraindicated. Using CT and MRI, you can obtain accurate images of the brain, determine how much the size of the ventricular system deviates from the norm, and whether there are neoplasms or hemorrhages in the medulla.

It is recommended to undergo an ultrasound of the brain for children in the first month of life if pregnancy or childbirth was accompanied by complications. If the ventricles are enlarged but there are no neurological symptoms, it is recommended to be re-examined after three months.

Dimensions of the III and IV ventricles

Reference values ​​for the transverse dimensions of the third and fourth ventricles (Table 1)[9]

Table 1

Bicaudal index

The bicaudal index (BCI) is a commonly used linear measure of the lateral ventricles (Fig. 3). To account for natural changes in ventricular size with aging, (BCI) is then divided by the upper limits of “normal” age to calculate the relative bicaudal index [6–7].

BKI = A/B, where A = width of the frontal horns at the level of the caudate nuclei; B = brain diameter at one level [6-7].

Table 2 Normal BCI values ​​stratified by age group.

The diagnosis of hydrocephalus is established when the BCI is greater than 1. Normative values ​​determined in subjects without neurological disease in the mid-to-late 1970s [6-7]. Divide the width of the frontal horns of the lateral ventricles, at the level of the caudate nuclei, by the corresponding diameter of the brain. Take the measurement on a section that includes the foramen Monro [6-7].

Fig. 3 Measurement of the bicaudal index (left) and asymmetry of the lateral ventricles in the absence of an organic cause (right).

Symptoms of the disease in an infant

Since the outflow of cerebrospinal fluid is impaired, it remains in large quantities in the head, while the intracranial pressure in the newborn increases, and swelling of the tissues, gray matter, and cerebral cortex increases. Due to pressure on the brain, blood supply is disrupted and the functioning of the nervous system deteriorates.

If the growth of the horns of the ventricles of the brain is accompanied by hydrocephalus, the child’s skull bones move apart, the fontanel bulges and tenses, the frontal part of the head can significantly exceed the facial part in size, and a network of veins protrudes on the forehead.

When the ventricle of the brain is enlarged in a newborn or pathological asymmetry of the lateral ventricles is noted, the child experiences the following neurological symptoms:

• Impaired tendon reflex, increased muscle tone.
• Visual impairment: inability to focus, squint, constantly downturned pupils.
• Trembling of limbs.
• Walking on tiptoe.
• Low manifestation of basic reflexes: swallowing, sucking, grasping.
• Apathy, lethargy, drowsiness.
• Irritability, loudness, capriciousness.
• Poor sleep, jumping up in sleep.
• Poor appetite.

One of the most striking symptoms is frequent regurgitation, sometimes vomiting. Normally, a child should burp only after feeding - no more than two tablespoons at a time. Due to the fact that when intracranial pressure increases (it is provoked by excessive accumulation of cerebrospinal fluid in the cavity of the cranium), the vomiting center in the fourth ventricle at the bottom of the rhomboid fossa is irritated, the frequency of regurgitation in a newborn increases significantly (more than twice after feeding and later).

The acute, rapid development of the disease provokes severe headaches, which is why the child constantly screams loudly and monotonously (brain scream).

Asymmetry of the lateral ventricles

Most reports and articles agree that asymmetry of the lateral ventricles in the absence of organic pathology is a normal anatomical variant in most cases (Fig. 3 right).

The prevalence of asymmetry of the lateral ventricles in the study population (patients with complaints of headaches or undergoing a medical examination, without complaints, as well as all of them without identified organic pathology of the brain) was 6.1%. In patients, a larger ventricle was more often found on the left side than on the right side (left = 70.0%, right = 30.0%). The density of various brain regions was similar on both sides in the ALV and control group [3].

According to other data, the prevalence of asymmetry in the size of the lateral ventricle in individuals without signs of an underlying etiology is 5-12% [3-5].

Study conclusion: The clinician should be alert to detect ALV on an unsatisfactory CT scan, especially in cases with severe asymmetry or diffuse ventricular enlargement, and to look for possible associated disorders [3].

In a Canadian study conducted in 1990 with a group of 249 patients, both headaches and seizures were more common in patients with asymmetrical lateral ventricles [4]. In a more recent Turkish study of 170 patients, headache was more common in patients with asymmetrical lateral ventricles than in those with “normal” ones (control group), otherwise there was no significant difference in presentation between the two groups [3].

Asymmetry of the lateral ventricles clearly has an objective cause in patients with the presence of organic pathology, such as: the volumetric effect of an intracranial mass (tumor, inflammatory process or hematoma) and as a result of residual changes leading to stretching of the cavity of the lateral ventricle against the background of the loss of a certain volume of nervous tissue ( so-called ex-vacuo hydrocephalus).

Clinical manifestations of ventricular dilatation

The ventricles not only store cerebrospinal fluid, they also secrete cerebrospinal fluid into the subarachnoid space. An increase in fluid secretion and a deterioration in its outflow leads to the fact that the ventricles stretch and enlarge.

An increase in the ventricular structures of the brain (dilatation, ventriculomegaly) may be a normal variant if a symmetrical expansion of the lateral ventricles is detected. If there is asymmetry of the lateral structures, the horns of only one of the ventricles are enlarged, this is a sign of the development of a pathological process.

Not only the lateral ventricles of the brain can become pathologically enlarged; the normal production and excretion of cerebrospinal fluid may be disrupted in the third or fourth. There are three types of ventriculomegaly:

• Lateral: enlargement of the left or right part of the ventricular structures, expansion of the posterior ventricle.
• Cerebellar: the medulla oblongata and cerebellar region are affected.
• When pathological release of cerebrospinal fluid occurs between the visual tuberosities, in the frontal part of the head.

The disease can occur in mild, moderate, severe form. In this case, not only an expansion of the cavities of the ventricles of the brain is noted, but also a disruption in the functioning of the child’s central nervous system.

There is normal symmetrical oversizing of the lateral ventricular structures when the child is large, has a large head or an unusual skull shape.

Volume of the ventricular system

Normal values ​​of the volume of the ventricular system (in Table 3) [8].

Table 3

Source

1. Methodological manual for students of medical institutes. Compiled by: Gubsky L.; Borkina P.; Abovich Y.; Evstifeeva N.; Timakov V. link
2. Orlov Yu.A. Hydrocephalus. – Kyiv, 1995. – 75 p.
3. Cerebral lateral ventricular asymmetry on CT: how much asymmetry is representing pathology? Kiroğlu Y1, Karabulut N, Oncel C, Yagci B, Sabir N, Ozdemir B.Surg Radiol Anat. 2008 May;30(3):249-55. doi:10.1007/s00276-008-0314-9. Epub 2008 Feb 6. link
4. Grosman H, Stein M, Perrin RC, Gray R, St Louis EL. Computed tomography and lateral ventricular asymmetry: clinical and brain structural correlates. (1990) Canadian Association of Radiologists journal = Journal l'Association canadienne des radiologists. 41 (6): 342-6. Pubmed
5. Shapiro R, Galloway SJ, Shapiro MD. Minimal asymmetry of the brain: a normal variant. (1986) A.J.R. American journal of roentgenology. 147(4):753-6. doi:10.2214/ajr.147.4.753 - Pubmed
6. Gijn, Jan van et al. “Acute Hydrocephalus After Aneurysmal Subarachnoid Hemorrhage.” Journal of Neurosurgery 63.3 (1985): 355-362. link
7. Dupont, Stefan and Alejandro A Rabinstein. “CT Evaluation Of Lateral Ventricular Dilation After Subarachnoid Hemorrhage: Baseline Bicaudate Index Balues.” Neurological Research 35.2 (2013): 103-106. link
8. Morphometric Changes in Lateral Ventricles of Patients with Recent-Onset Type 2 Diabetes Mellitus. Junghyun H. Lee, Sujung Yoon, Perry F. Renshaw, Tae-Suk Kim, Jiyoung J. Jung, Yera Choi, Binna N. Kim, Alan M. Jacobson, In Kyoon Lyoo. Published: April 4, 2013 “PLOS one”.link
9. "Third and Fourth Cerebral Ventricular Sizes among Normal Adults in Zaria-Nigeria." Ahmed Umdagas Hamidu, Solomon Ekott David, Sefiya Adebanke Olarinoye-Akorede, Barnabas Danborno, Abdullahi Jimoh, Olaniyan Fatai. Year:2015, Volume:2, Issue:2, Page:89-92 link