Malformations of Cortical Development Revisited: Can We Improve Prenatal Sonographic Diagnostic Rates?

Despite the profound implications, prenatal diagnosis of malformations of cortical development (MCD) remains a challenge. The aims of this study were to identify the neurosonographic features in a large cohort of fetuses with MCD and to propose markers for screening in axial planes. We performed a 10-year retrospective study of fetuses with MCD assessed in a tertiary centre in Israel. MCD was confirmed by pathology, genetics, CMV-PCR positive, or postnatal imaging. Neurosonographic scans comprised evaluation in sagittal, coronal and axial planes and the findings were classified according to their location, symmetry and correlation to the expected features for gestational age. We included 55 cases MCD with a mean gestational age at first scan of 26.5 weeks (SD ±4.92). Overall, 35% of cases were assessed at ≤24 weeks and only 15% were primarily referred due to the suspicion of MCD in a routine scan. Coronal planes were most informative, depicting at least one abnormal feature in 89% of cases, compared to 87% and 85% from sagittal and axial planes, respectively. An abnormal anterior complex morphology was the most frequent finding in both axial (61%) and coronal planes (72%). In axial planes an abnormal ventricular morphology (asymmetry, irregular walls, abnormal shape or clefts) was observed in 50% and abnormal Sylvian fissure shape (proximal, distal or both) was found in 48% of cases. Of note, ventriculomegaly and a head circumference below or above 2SD were observed in 33% and 18% of cases and were not strong screening features. The most common associated brain findings were callosal dysgenesis (49%) and midbrain-hindbrain anomalies (27%). The addition of the anterior complex and Sylvian fissure morphology to basic axial imaging planes of the fetal brain may increase the suspicion of MCD, allowing referral for dedicated neurosonographic evaluation and further workup. The coronal planes remain the most representative in comparing both sides of the brain and the anterior complex in high resolution.