Abstract
BACKGROUND AND PURPOSE
In several countries, laws and regulations allow abortion for medical reasons within 24–25 weeks of gestational age. We investigated the diagnostic value of prenatal MR imaging for brain malformations within 25 weeks of gestational age.
MATERIALS AND METHODS
We retrospectively included fetuses within 25 weeks of gestational age who had undergone both prenatal and postnatal MR imaging of the brain between 2002 and 2014. Two senior pediatric neuroradiologists evaluated prenatal MR imaging examinations blinded to postnatal MR imaging findings. With postnatal MR imaging used as the reference standard, we calculated the sensitivity, specificity, positive predictive value, and negative predictive value of the prenatal MR imaging in detecting brain malformations.
RESULTS
One-hundred nine fetuses (median gestational age at prenatal MR imaging: 22 weeks; range, 21–25 weeks) were included in this study. According to the reference standard, 111 malformations were detected. Prenatal MR imaging failed to detect correctly 11 of the 111 malformations: 3 midline malformations, 5 disorders of cortical development, 2 posterior fossa anomalies, and 1 vascular malformation. Prenatal MR imaging misdiagnosed 3 findings as pathologic in the posterior fossa.
CONCLUSIONS
The diagnostic value of prenatal MR imaging between 21 and 25 weeks’ gestational age is very high, with limitations of sensitivity regarding the detection of disorders of cortical development.
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Fellows’ Journal Club
The authors retrospectively evaluated 109 fetuses within 25 weeks of gestational age who had undergone both prenatal and postnatal MR imaging of the brain between 2002 and 2014, and using the postnatal MRI as the reference standard, they calculated the sensitivity, specificity, positive predictive value, and negative predictive value of the prenatal MRI in detecting brain malformations. Prenatal MR imaging failed to detect correctly 11 of the 111 malformations. They conclude that diagnostic value of prenatal MRI for brain malformations within 25 weeks of GA is very high, despite limitations of sensitivity in the early detection of disorders of cortical development, such as polymicrogyria and periventricular nodular heterotopias.