Fetal ventriculomegaly is the most common abnormality of the central nervous system, affecting 1% of fetuses and associated with cognitive, language, and behavioral impairment in childhood. The neurodestructive outcome is predicted in part by two-dimensional ventricular size in the absence of other abnormalities. We hypothesized that isolated fetal ventriculomegaly is a marker of altered brain development characterized by relative proliferation and aimed to quantify brain growth using volumetric magnetic resonance imaging in fetuses with isolated ventriculomegaly.

Volumetric analysis of ventricles and supratentorial brain structures was performed on 3D reconstructed data sets. Fetuses with isolated ventriculomegaly had increased volumes of brain parenchyma compared with control cohorts with expansion limited to gray skin. Extrasecretory cerebrospinal fluid and the third and fourth ventricles were also enlarged. White matter, basal ganglia, and thalamic volumes did not differ significantly between cohorts. The presence of relative cortical overgrowth in fetuses with ventriculomegaly may represent a neurobiological substrate for the cognitive, language, and behavioral deficits in these children.

In the fetus, ventriculomegaly is the most common central nervous system abnormality, occurring in 1% of the fetal population. During normal development, the size of the lateral ventricles remains relatively stable from 14 gestational weeks until birth, with an average atrial diameter of 4 mm. Neurodestructive outcome in children with fetal ventriculomegaly is variable and primarily includes cognitive, language, and behavioral deficits. Classification into mild, moderate, and severe is currently the best predictor of outcome.

The overall risk of neurological abnormality in isolated mild to moderate ventriculomegaly is 12%, increasing to over 75% in severe cases, even when congenital infection and abnormal karyotype are excluded. Understanding the neurobiological substrate and variability of these abnormal findings will inform ongoing clinical treatment and parental counseling.

Fetal ventriculomegaly is diagnosed when the atrial diameter is equal to or greater than 10 mm. The calipers are placed within the low signal intensity of the inner edge of the ventricular wall and perpendicular to the long axis of the ventricle. Neonatal ventriculomegaly is often associated with posthemorrhagic or anatomical obstruction to the flow of cerebrospinal fluid or secondary to white matter atrophy; however, these are unusual causes in the fetus, where the reason for the dilatation of the lateral ventricles is unknown to most.

Ventriculomegaly is associated with variable brain growth in a fetal rat model, children with Soto syndrome, hemimegalencephaly, and high-functioning children with autism. We hypothesize that fetal ventriculomegaly is a marker of altered brain development characterized by relative brain proliferation. The aim of this study was therefore to quantify brain tissue volumes in fetuses with isolated ventriculomegaly using antenatal magnetic resonance.

Ethical approval was granted by Hammersmith Hospitals Ethics Committee and informed consent was obtained from all participants. Fetuses with unilateral or bilateral ventricular dilatation on conventional ultrasound at approximately 20 weeks were referred to our department for further evaluation of brain development. Three fetuses had normal routine ultrasound scan abnormalities and were diagnosed with ventriculomegaly on late ultrasound scans.

Patients with additional brain abnormalities, positive infection screening and chromosomal abnormalities, intrauterine growth restriction, twin pregnancies, maternal drug consumption, or poor image quality were excluded from this study. There may also be breaks or signs of tissue trauma and distortion. The obstruction may be associated with a large or enlarging occipital frontal circumference and the appearance of cerebral images of air bubbles with reduced extracerebral space, indicating increased pressure within the ventricles and intracranial cavity.

Sometimes structural obstructions may be directly visible, such as a large cyst, hemorrhage, or indirectly, such as secondary dilatation of the third ventricle due to aqueductal stenosis. In addition, changes in signal intensity of adjacent white matter may be detected as a result of edema due to increased pressure, presumably secondary to impaired venous drainage.

Samsung medical equipment

Thus, multiple sets of images were acquired in three orthogonal planes with overlapping slices to reprogram the fetal brain and ensure that every part of the brain was culled even with significant movement. All checks were then reviewed for image quality, and sections affected by motion artifacts where anatomical detail was lost were removed from subsequent analysis. The images were registered to a common coordinate space to align the resulting fragments.

The reconstructed 3D volumetric datasets have the high resolution, high signal-to-noise ratio, and complete brain coverage needed for robust volumetric analysis. Visual analysis of all acquired images was performed to exclude additional abnormalities and confirm appropriate appearance for pregnancy.

Medical journal on echography

The 3D embryonic brain volume data were aligned to standard axial, coronal, and sagittal projections, and voxel size was interpolated to aid visual display and to help place anatomical bounding surfaces. Total lateral ventricular volume was defined as the volume of both the left and right lateral ventricles, including the choroid plexus but excluding the third and fourth ventricles, membranous septum pellucida, and vergi. Volume lateral ventricle refers to the volume of each lateral ventricle.

The fourth ventricular volume was limited to the superior medullary velum, mainly the ape, the anterior arms, the middle cerebellar peduncles laterally, and the vermis posteriorly. Cardiac cortex, basal ganglia, and thalami were manually segmented in a subset of cases due to the extensive work required for manual segmentation. The duration of manual segmentation of gray cortex in a 28-week fetus was 8 hours. 19 cases were selected from 20 to 37 weeks of gestation.

Substructures of the basal ganglia included the coniferous, putaminal, globus pallidus, and nuclear supplies and excluded the anterior and posterior limbs of the internal capsule. Thalamic segmentation included all nuclei defined by tissue contrast of the internal capsule in the transverse direction, the atrial region of the lateral ventricles posteriorly, the third ventricle medially, and the hypothalamus anteriorly. White matter volumes were calculated by subtracting the cerebral cortex, basal ganglia, and thalamic volumes from the total brain tissue volume.

Atrial diameter was measured according to the International Society of Ultrasound in Obstetrics and Gynecology guidelines at the atrium level. Data were log transformed to achieve a normal distribution. A significance level of 05 was considered significant. The intra- and inter-class correlation coefficients were equal for 99. The average difference between intra-media for cortical volume was 2%, and the average difference between rasters was 7%. A total of 89 fetuses were enrolled as normal controls: 31 were excluded according to our exclusion criteria.

Two fetuses were tested twice during pregnancy. In 33 of 48 fetuses, ventriculomegaly was unilateral. Fifteen fetuses were screened twice, and one was scanned 3 times during pregnancy. The lateral ventricles were assessed using the atrial diameter, the volume of each lateral ventricle, and the total volume of the lateral ventricle. Atrial diameter and lateral ventricle volume correlated well. There was no significant difference in atrial diameter, left or right lateral ventricular volumes, or total lateral ventricular volume between sexes in the control cohort; however, there was a trend toward larger ventricular measurements in men.

In males, the left lateral ventricle was significantly larger than the right, while in females this difference was not significant. Ventricular measurements in normal controls. There was a slight increase in third ventricle volume with a relative growth rate of 098% per week, increasing from 074 cm 3 at 22 weeks to 359 cm 3 per week.

Volumetric results for the control and ventriculomegaly cohorts. Note: Volumetric results for control and ventriculomegaly cohorts. Relative growth rate is the percentage increase in volume relative to the average volume of the structure.

What to do if the fetus has a stomach pathology detected by ultrasound?

Total volumes of cortical gray matter, basal ganglia, thalamus, and white matter were measured in 19 control cases and the results are presented in the table. The volume of the cortex increased from 01 cm 3 at 22 weeks to 58 cm 3 at 38 weeks. The thalamic volume increased exponentially with a relative growth rate of 13% per week from 88 cm 3 per week to 22-52 cm 3 per week. White matter volume increased at a relative growth rate of 27% per week from 15 cm 3 at week 22-25 cm 3 at 38 weeks.

Correlations with Ventricular Size in the Control Cohort

There was no significant correlation between the total volume of the lateral ventricle and the cortex, basal ganglia, and white matter. Correlation of total ventricular volume and intracranial volumetric measurements. Note: Correlation of total ventricular volume and intracranial volumetric measurements. Spearman's correlation coefficient is presented for each relationship. The correlations performed were not adjusted for gestational age.