Corpus Callosum to Choroid Plexus Distance for the Prenatal Diagnosis of Partial Agenesis or Hypoplasia of the Corpus Callosum: A Multicenter Study.

Objectives: Prenatal diagnosis of partial agenesis (pACC) or hypoplasia of the corpus callosum (CC) is hindered by the lack of objective and reproducible ultrasound signs. The aim of this study was to report the role of a new ultrasound sign, the distance between the choroid plexus (CP) of the third ventricle and the distal part of the CC, in identifying fetuses with partial agenesis (pACC) or hypoplasia of CC.

Methods: Retrospective multicenter case-control study including fetuses with pACC or hypoplasia of the CC confirmed at post-natal imaging or autopsy. The distance between the CP of the third ventricle and its ratio with the length of the CC were compared with unaffected cases on stored images assessed by 2 different examiners. Intraclass correlation, Bland-Altman, univariate, and multivariate logistic regression analyses were used to analyze the data.

Results: One hundred and four (29 with pACC or hypoplasia of the CC and 75 controls) were included in the analysis. At univariate analysis, fetuses with pACC or hypoplasia had a larger transverse diameter (3.9 ± 0.7 versus 5.3 ± 1.6 mm; P < .001) and an increased area (31.6 ± 8.8 versus 41.6 ± 15.6 mm²; P < .001) of the CSP compared to unaffected cases. Fetuses with pACC or hypoplasia of the CC had a shorter distance between the CP of the third ventricle and the distal part of the CC (1.6 ± 0.9 versus 8.4 ± 1.8; P < .001) and a higher ratio between the length of the CC and the distance between the CP of the third ventricle and the CC (13.5 ± 9.3 versus 2.6 ± 0.5; P < .001) compared to controls. At multivariate logistic regression analysis, the distance between the CP and the CC (OR: 0.67, 95% CI 0.5-0.7, per 1 mm increase; P < .001) and the ratio between the CC length and the distance between the CP and the CC (OR: 1.4, 95% CI 1.0-1.6; per 1 mm increase; P < .001) were independently associated with pACC or hypoplasia of the CC.

Conclusions: Fetuses with pACC or hypoplasia of the CC had a shorter distance between the distal part of the CC and the CP of the third ventricle and a higher ratio of this measurement with the length of the CC. Further prospective study aimed at longitudinally evaluate the relationship between the CC and the CP of the third ventricle are needed to confirm these findings and to elucidate whether these measurements can be integrated in the diagnostic algorithm applied to fetuses with suspected pACC or hypoplasia of the CC.