Feasibility study of prenatal ultrasound in the evaluation of normal fetal sylvian fissure maturation by simplified grading / 中华超声影像学杂志

ABSTRACT

Objective:To observe the morphological changes of the sylvian fissure on the transthalamic section of fetal brain at 20-32 weeks, and grade the fetal sylvian fissure development by means of a simple scoring system and explore its clinical feasibility.Methods:From September 2018 to June 2020, 487 normal single fetuses of 20-32 weeks were examined in Shenzhen Maternal and Child Health Hospital Affiliated to Southern Medical University. The sylvian fissure maturation was analyzed on the transthalamic section of fetal brain at 20-32 weeks and was graded from 0 to 5 un-visualized (grade 0), shallow arc (grade 1), obtuse-angled platform (grade 2), right-angled platform (grade 3), acute-angled platform (grade 4), and closed operculum (grade 5). The pregnancy outcomes and gestational age were recorded.Statistical analysis was performed by SPSS 20.0 software using box plot, Mann-Whitney U test, Weighted Kappa coefficient. Results:Left sylvian fissuer grades were obtained in 280 fetuses and right sylvian fissure grades were obtained in 247 fetuses. The fetal sylvian fissure maturation at 20-32 weeks was graded from 0 to 5, which increased with advancing gestation. Grade 0 only appeared in 3 fetuses at 20 weeks, and 99.4% fetuses at 20 weeks had grade ≥1. Grade 1 appeared in 20-22 weeks, grade 2 in 20-25 weeks, grade 3 in 22-26 weeks, grade 4 in 25-32 weeks, and grade 5 in 27-32 weeks. Box-plot and Mann-Whitney U test showed that gestational week distribution of sylvian fissure at all grades was symmetric on both sides ( P>0.05). The Weighted Kappa coefficients were 0.857(95% CI=0.750-0.957) and 0.939 (95% CI=0.859-1.000), respectively, with strong consistency regarding inter- and intra-observer agreements. Conclusions:Fetal sylvian fissure maturation at 20-32 weeks can be evaluated by means of a simple scoring system with symmetrical grading of both sides.