Ultrasound and MR imaging findings in prenatal diagnosis of craniosynostosis syndromes.

BACKGROUND: Craniosynostosis syndromes are uncommonly encountered in the prenatal period. Identification is challenging but important for family counseling and perinatal management.

OBJECTIVE: This series examines prenatal findings in craniosynostosis syndromes, comparing the complementary roles of US and MRI and emphasizing clues easily missed in the second trimester.

MATERIALS AND METHODS: Six prenatal cases evaluated from 2002 through 2011 were retrospectively reviewed. Referral history, gestational age, and sonographic and MRI findings were reviewed by three pediatric radiologists. Abnormalities of the calvarium, hands, feet, face, airway and central nervous system were compared between modalities.

RESULTS: The diagnosis was Apert syndrome in three, Pfeiffer syndrome in two and Carpenter syndrome in one. The gestational age at evaluation ranged from 21 to 33 weeks. All six were evaluated by MRI and US, with two undergoing repeat evaluation in the third trimester, yielding a total of eight MRIs and US exams. The referral history suggested cloverleaf skull in two cases but did not suggest craniosynostosis syndrome in any case. In four, the referral suggested central nervous system (CNS) findings that were not confirmed by MRI; additional CNS findings were discovered in the remaining two. In four cases, developing turricephaly resulted in a characteristic "lampshade" contour of the fetal head. Hypertelorism and proptosis were present in five, with proptosis better appreciated by MRI. Digit abnormalities were present in all, seen equally well by MRI and US. Lung abnormalities in the second trimester in one fetus resolved by the third trimester.

CONCLUSION: Prenatal diagnosis of craniosynostosis syndromes is difficult prior to the third trimester. MRI and US have complementary roles in evaluation of these patients.