Ultrasonography of the peri- and intraventricular areas of the fetal brain between 26 and 36 weeks' gestational age; a comparison with neonatal ultrasound.

OBJECTIVES

To determine to what extent the peri- and intraventricular areas of the fetal brain can be visualized in coronal and sagittal planes using high-frequency transvaginal ultrasound.

DESIGN

In a longitudinal study, fetuses of 30 low-risk pregnancies were studied at 26, 28, 30, 32, 34 and 36 weeks' gestational age. The neonates were examined within the first week of life. Visualization of the peri- and intraventricular areas was systematically scored in six coronal and five sagittal planes. The degree of echogenicity of the periventricular area was assessed. Inter- and intra-observer agreements were calculated.

RESULTS

For fetuses in the cephalic position, the highest percentages of visualization of the planes were obtained between 26 and 32 weeks' gestational age (> 70% in four coronal and three sagittal planes). Transient periventricular echodensities were observed at 26 and 28 weeks' gestational age in 6/39 observations in the cephalic position. Small choroid plexus cysts were found in three fetuses with the changes persisting in two until after birth. Seven neonates developed mild periventricular echodensities/translucencies not present during fetal development. The mean interobserver agreement was 0.77 (95% confidence interval (CI) 0.73-0.81). The intra-observer agreement varied between 0.48 and 0.72 (mean 0.6, 95% CI 0.47-0.75).

CONCLUSIONS

Transvaginal ultrasonography can be applied as a diagnostic tool to evaluate the peri- and intraventricular areas of the fetal brain. Transient periventricular densities can be encountered between 26 and 28 weeks. Term low-risk neonates may develop transient periventricular densities or translucencies.