Prenatal diagnosis of agnathia-holoprosencephaly: three-dimensional imaging by helical computed tomography

We report a case of agnathia-holoprosencephaly which was prenatally diagnosed based on helical computed tomography (CT) images obtained at 23 weeks of gestation. Ultrasound examination first showed the presence of alobar holoprosencephaly, but the facial structures were not clearly detailed. However, three-dimensional imaging by helical CT precisely demonstrated the most striking feature of agnathia: absence of the mandible. This technique provided us valuable information that contributed to the in utero diagnosis. In utero helical CT is a useful examination tool for the diagnosis of osteogenic abnormalities.