Objectives: To report the rate of visualization of the pericallosal artery (PCA) in the first trimester of pregnancy (11-14 weeks).
Methods: Prospective observational study of consecutive fetuses undergoing first trimester risk assessment for chromosomal anomalies. The presence of PCA was assessed in a midsagittal view of fetal brain using high-definition power Color Doppler. A normal course of the PCA was defined as the visualization of an artery emerging from the anterior cerebral artery running parallel the corpus callosum (CC). The reference standard was the visualization of CC and PCA between the 20 and 22 weeks of gestation. We also performed a systematic review and meta-analysis of the published literature. Multivariate logistic regression and random-effect meta-analyses of proportion were used to analyze the data.
Results: Cohort study: Five-hundred women were included. PCA was identified trans-abdominally or transvaginally at 11-14 weeks of gestation in 98.8% (95% CI 97.4-99.6: 494/500); of the four cases of PCA not identified one had a diagnosis of complete agenesis of the corpus callosum during the anomaly scan which was confirmed at birth. Systematic review of the published literature: Six studies (1093 fetuses, including the present series) were included. The PCA was detected at the 11-14 weeks scan and confirmed to co-exist with a normal CC at time of the anomaly scan in 96.9% (95% CI 93.8-99.0); 20.6% (95% CI 5.7-41.7) of fetuses with no clear identification of the PCA at the 11-14 weeks scan had a normal appearance of the CC at the time of anomaly scan.
Conclusion: Prenatal ultrasonography has a high diagnostic accuracy in detecting PCA in the first trimester. Visualization of the PCA at the time of 11-14 scan is highly specific for the presence of a normal CC later in pregnancy.
Keywords: corpus callosum; first trimester; pericallosal artery; ultrasound.
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