Hyperdense posterior falx in the neonate

Abstract

Objective: Hyperdense posterior falx and/or torcula on unenhanced CT scans is associated with sagittal sinus thrombosis in adults. However, the validity of this finding in newborns is unknown.

Materials and methods: A prospective review was performed from September 1995 to November 1996, evaluating head CT scans of infants during their first week of life.

Results: Eleven neonatal head CT scans revealed a hyperdense posterior falx, suggestive of sagittal sinus thrombosis. Further imaging (7 ultrasound and 4 magnetic resonance imaging examinations) revealed no evidence of venous thrombosis in 10 of the 11 infants.

Conclusion: Predominantly unmyelinated neonatal brain and increased hematocrit of neonatal blood probably contribute to the false impression of hyperdense posterior falx/torcula on neonatal head CT scans.