Frontal Paraventricular Cysts: Refined Definitions and Outcomes

BACKGROUND AND PURPOSE: Frontal paraventricular cystic changes have a varied etiology that includes connatal cysts, subependymal pseudocysts, necrosis, and enlarged perivascular spaces. These may be difficult to distinguish by neuroimaging and have a variety of associated prognoses. We aim to refine the neuroimaging definition of frontal horn cysts and correlate it with adverse clinical conditions.

MATERIALS AND METHODS: In this cross-sectional study, the pre- and postnatal neuroimaging database at a quaternary referral children’s hospital was searched for all reports containing “frontal horn cysts,” “periventricular cysts,” or “connatal cysts” after internal review board exemption. Frontal paraventricular abnormalities were categorized as either cysts, necroses, enlarged perivascular spaces, caudothalamic groove subependymal pseudocysts, frontal horn asymmetries, intraventricular septations, or ependymal vessels based on location and appearance. Cyst number, size, location, morphology, and signal/attenuation/echotexture were documented, as were additional brain abnormalities. Clinical outcomes were recorded when available. Fisher exact and χ² tests were used to evaluate categoric data associations and Kruskall-Wallis tests were employed to compare the medians among groups.

RESULTS: Two hundred five brain imaging examinations (148 MRI; 55 ultrasound [US]; 2 CT) from 110 distinct subjects (5 fetal: median 29.3, mean 27.5, and range 22.4 to 32.8 gestational weeks; 105 postnatal: mean 2.5 years, median 15 days, range 0 days to 19 years) were included. Seventy-one examinations (35%) were initially diagnosed as connatal cysts but, instead, represented necrosis (n = 23), enlarged perivascular spaces (n = 20), caudothalamic groove germinolytic cysts (n = 11), septations/adhesions (n = 10), ventricular asymmetries (n = 6), and a blood vessel (n = 1). These entities differed in size, shape, location, and orientation (P < .001). Congenital heart disease (P < .04) and gastrointestinal (P < .04) disorders were more common in subjects with frontal cysts and necrosis than in subjects with enlarged perivascular spaces; however, the frontal cyst and necrosis groups showed no differences in outcome (P > .05).

CONCLUSIONS: Frontal paraventricular cystic changes represent a common interpretive dilemma. Enlarged perivascular spaces should be distinguished from other frontal cystic changes, which portend a more guarded prognosis, whether necrotic or otherwise.