Heterogeneity in defining fetal corpus callosal pathology: systematic review

Area of Science:

• Fetal Medicine
• Neuroimaging
• Systematic Review

Background:

• Fetal anomalies of the corpus callosum (CC) present diagnostic challenges, particularly when isolated.
• Existing prenatal imaging literature since 1985 lacks standardized terminology for non-agenesis CC abnormalities.

Purpose of the Study:

• To systematically review the literature on prenatally diagnosed corpus callosum (CC) abnormalities.
• To focus on the terminology used for CC abnormalities beyond complete agenesis.
• To assess the heterogeneity in nomenclature and definitions within the prenatal literature.

Main Methods:

• Systematic literature search adhering to PRISMA guidelines.
• Inclusion of prospective/retrospective case series or cohort studies reporting fetal CC anomalies.
• Evaluation of study quality and risk of bias using established scales.

Main Results:

• 24 studies representing 1135 cases of CC anomalies were included in the final analysis.
• 49% of cases involved complete agenesis of the corpus callosum.
• Non-agenesis CC anomalies were described using 9 other terms, with 5 terms having multiple definitions.

Conclusions:

• Significant heterogeneity exists in the prenatal literature regarding terminology and definitions for CC anomalies, unlike the postnatal literature.
• This lack of standardized definitions impedes the development of large patient cohorts for genetic and neurodevelopmental outcome studies.
• Developing a simpler, standardized categorization of prenatal CC anomalies is recommended to align with postnatal literature and improve patient counseling.