Antenatal diagnosis of agenesis of the corpus callosum

•The diagnosis of agenesis of the corpus callosum in the fetus is challenging on ultrasonography.•Agenesis of the corpus callosum is frequently overcalled and missed on ultrasonography.•If suspicion of agenesis of the corpus callosum is raised, should be performed.

AimTo estimate the diagnostic performance of ultrasound in detecting agenesis of the corpus callosum (ACC).Materials and methodsA retrospective review was performed of 1722 in utero MRI examinations. All cases were identified in which the fetus had been referred from ultrasonography with a diagnosis of ACC and those in which ACC was given as a diagnosis on the in utero MRI study. The MRI was assumed to provide the correct diagnosis of ACC and descriptive statistics of diagnostic accuracy for ultrasound were calculated.ResultsOf the 1722 ultrasound examinations performed, 121 had a diagnosis of ACC and approximately 50% were confirmed at MRI. Forty-two fetuses with ACC not suspected at ultrasonography were also identified at MRI. Ultrasonography had a positive predictive value of 47% (95% CI: 38–56%) and a negative predictive value of 97% (95% CI: 96–98%) for detecting ACC.ConclusionUltrasound is poor in diagnosing ACC and in utero MRI should be performed if there is any suspicion on antenatal ultrasonography.