1455: Combined Prenatal Ultrasound and Fetal MR Imaging in Diagnosis of Fetal Arachnoid Cyst of 2 Cases

Abstract

Arachnoid cyst is accumulation of cerebrospinal fluid within the arachnoid membrane due to maldevelopment of the arachnoid or secondary to trauma or infection. Neonatal arachnoid cyst is rare, representing 1% of intracranial masses, with 50-60% occurring in the middle cranial fossa. The prognosis is generally good. However, neonatal morbidity and mortality depend on the location of the cyst and complications, such as acute mass effect by intracystic hemorrhage or the development of a subdural hygroma or hematoma.