胎児発育不全における大脳皮質成熟および溝発達の神経超音波評価

This study aimed to investigate the effect of fetal growth restriction (FGR) on cortical maturation and fissure development using detailed neurosonography. We compared cortical grades and fissure measurements between FGR and healthy fetuses to determine if growth restriction is linked to delayed cortical maturation in specific regions.

This observational case-control study included singleton pregnancies at 31-35 weeks of gestation between January 2025 and September 2025. FGR was diagnosed according to the Delphi consensus criteria. All participants underwent obstetric ultrasonography, fetoplacental Doppler, and fetal neurosonography. The depths of the Sylvian, parieto-occipital, calcarine, and cingulate fissures, as well as the insula, were measured and normalized to biparietal diameter (BPD). Cortical maturation was assessed using the Pistorius grading system.

A total of 148 fetuses were analyzed (74 FGR, 74 controls). The FGR group showed higher uterine artery pulsatility index (PI) (P = .015) and lower middle cerebral artery (MCA) PI (P < .001). Neurosonography revealed significantly shallower parieto-occipital (P < .001), calcarine (P < .001), and cingulate (P < .001) fissures in the FGR group, while Sylvian fissure depth showed a nonsignificant trend (P = .057). After normalization to BPD, parieto-occipital/BPD and calcarine/BPD ratios remained significantly lower. In addition to quantitative fissure measurements, cortical maturation was evaluated. Only the Sylvian fissure showed a significantly lower maturation grade (P = .003). Cerebellar, vermian, and corpus callosum measurements were comparable.

FGR is associated with region-specific cortical developmental delay, predominantly involving the parieto-occipital, calcarine, and cingulate fissures, while infratentorial and commissural structures remain preserved. Neurosonography provides a practical, accessible, and reliable tool for detecting these subtle cortical alterations in high-risk pregnancies.