Neurosonography in the Assessment of Extracerebral Fluid Collections in Infants. Literature Review and Own Observations.

Background. Dilation of the external cerebrospinal fluid spaces is one of the most common echographic findings in children in the first months of life, while the echographic criteria of dilation of the external cerebrospinal fluid spaces remain debatable, and the clinical significance of dilation of the external cerebrospinal fluid spaces is unclear. Objective. To determine the normative echographic values of the external cerebrospinal fluid spaces in children. Materials and methods. The external cerebrospinal fluid spaces were measured in 628 conditionally healthy infants aged from 1 day to 11 months 29 days. In all cases, the external cerebrospinal fluid spaces were represented by the subarachnoid space. The results of our own   research are compared with the literature data. Results. The terminological diversity concerning the external cerebrospinal fluid spaces dilatation has been discussed and the literature data have been analyzed on its clinical significance. All the main provisions are illustrated by observations from our own archive. A statistically significant increase in the sizes of the external cerebrospinal fluid spaces in infants after the neonatal period has been revealed, with the maximum external cerebrospinal fluid spaces value observed in children aged 3–6 months (0.712 ± 0.039 mm in newborns and 2.585 ± 0.087 in infants aged 3–6 months, p < 0.01). The maximum value of the norm for infants under 1 month of life should be considered to be 2 mm, for children aged 3–6 months — up to 5 mm, 2–3 and 7–11 months — up to 4 mm. The average values of the external cerebrospinal fluid spaces in infants under one month are about 1 mm, in 2–11 months — 2–3 mm, which corresponds to most of the literature data. Conclusion 1. Normally, the external cerebrospinal fluid spaces in infants is represented only by the subarachnoid space. Dilation of the subdural space cannot be considered a normal variant. 2. The average value of the subarachnoid space in children of the first month of life does not exceed 1 mm, in infants older than the neonatal period it is 2–3 mm. The maximum value of the subarachnoid space should not exceed 2 mm in newborns, 3 mm at the age of 1 month, 4 mm at the age of 2 months, 5 mm in infants 3–6 months. In infants at the age 7–12 month, the subarachnoid space should not exceed 4 mm. 3. External cerebrospinal fluid spaces dilataton cannot be considered a completely benign condition and, regardless of the presence or absence of clinical manifestations, requires dynamic observation.

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