Improved neurodevelopmental prognostication in isolated corpus callosal agenesis: fetal magnetic resonance imaging‐based scoring system

Abstract

Objectives Corpus callosal agenesis (CCA) is one of the most common brain malformations and is generally associated with a good outcome when isolated. However, up to 25% of patients are at risk of neurodevelopmental delay, which currently available clinical and imaging parameters are inadequate to predict. The objectives of this study were to apply and validate a fetal magnetic resonance imaging (MRI) anatomical scoring system in a cohort of fetuses with isolated CCA and to evaluate the correlation with postnatal neurodevelopmental outcome. Methods This was a retrospective cohort study of cases of prenatally diagnosed isolated CCA (as determined on ultrasound and MRI), with normal karyotype and with known postnatal neurodevelopmental outcome assessed by standardized testing. A fetal brain MRI anatomical scoring system based on seven categories (gyration, opercularization, temporal lobe symmetry, lamination, hippocampal position, basal ganglia and ventricular size) was developed and applied to the cohort; a total score of 0–11 points could be given, with a score of 0 representing normal anatomy. Images were scored independently by two neuroradiologists blinded to the outcome. For the purpose of assessing the correlation between fetal MRI score and neurodevelopmental outcome, neurodevelopmental test results were scored as follows: 0, ‘below average’ (poor outcome); 1, ‘average’; and 2, ‘above average’ (good outcome). Spearman's rank coefficient was used to assess correlation, and inter‐rater agreement in the assessment of fetal MRI score was calculated. Results Twenty‐one children (nine females (42.9%)) fulfilled the inclusion criteria. Thirty‐seven fetal MRI examinations were evaluated. Mean gestational age was 28.3 ± 4.7 weeks (range, 20–38 weeks). All fetuses were delivered after 35 weeks' gestation with no perinatal complications. Fetal MRI scores ranged from 0 to 6 points, with a median of 3 points. Inter‐rater agreement in fetal MRI score assessment was excellent (intraclass correlation coefficient, 0.959 (95% CI, 0.921–0.979)). Neurodevelopmental evaluation was performed on average at 2.6 ± 1.46 years (range, 0.5–5.8 years). There was a significant negative correlation between fetal MRI score and neurodevelopmental outcome score in the three areas tested: cognitive (ρ = –0.559, P < 0.0001); motor (ρ = –0.414, P = 0.012) and language (ρ = –0.565, P < 0.0001) skills. Using fetal MRI score cut‐offs of ≤ 3 (good outcome) and ≥ 4 points (high risk for poor outcome), the correct prognosis could be determined in 20/21 (95.2% (95% CI, 77.3–99.2%)) cases. Conclusion By assessing structural features of the fetal brain on MRI, it may be possible to better stratify prenatally the risk of poor neurodevelopmental outcome in CCA patients. © 2020 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal Brain Development: Regulating Processes and Related Malformations

“…A variety of genetic, metabolic, disruptive, and toxic causes can result in abnormal CC development; however, the etiology of DCC remains unknown in many of the cases [ 75 ].…”

“…Destructive parenchymal brain lesions have been reported in 10% of ACC fetuses, raising the possibility of an acquired or genetic–metabolic underlying etiology [ 88 ]. Associated abnormalities of the Sylvian fissure and the hippocampus have been reported to aggravate the neurodevelopmental outcome [ 75 ]. The most common symptoms in individuals with ACC are delayed motor and cognitive functions, social and language deficits, and epilepsy.…”

“…According to a meta-analysis by D’Antonio et al [ 89 ], a normal neurodevelopmental outcome is expected in 76.0% (95% CI 64.3–86.1%) and 71.4% (95% CI 53.1–86.7%) of children with complete and partial prenatally diagnosed isolated ACC, respectively. A fetal brain MRI anatomical score based on evaluation of gyration, opercularization, temporal lobe symmetry, parenchymal lamination, hippocampal position, basal ganglia, and ventricular size has recently been developed to improve prognostication of postnatal neurodevelopmental outcome [ 75 ].…”

Fetal corpus callosum abnormalities: Ultrasound and magnetic resonance imaging role

“…Using advanced functional techniques in fetal MRI, such as diffusion tensor imaging in future studies, possibly enhances the evaluation of ACC and associated anomalies 66 . Recent studies also propose a score‐based systematic assessment of particular regions of the brain that enhanced the diagnostic power of MRI by the proper stratification of cases with high and low risks in isolated ACC 67,68 …”

“…66 Recent studies also propose a score-based systematic assessment of particular regions of the brain that enhanced the diagnostic power of MRI by the proper stratification of cases with high and low risks in isolated ACC. 67,68…”