THE SIZE OF THE INTRAVENTRICULAR AND EXTRAVENTRICULAR CEREBROSPINAL-FLUID COMPARTMENTS IN CHILDREN WITH IDIOPATHIC BENIGN WIDENING OF THE FRONTAL SUBARACHNOID SPACE

The aim of this study was to quantify the intra- and extra-ventricular cerebrospinal fluid (CSF) spaces in children with benign enlargement of the frontal subarachnoid space (BE). The infra-and supratentorial C SF compartments were measured in 61 CT examinations of children with B E, 3-27 months old, and compared with those of 96 CT examinations cons idered normal. Measurements of the ventricular system, and the pontine and chiasmatic cisterns were related to cranial size. In all children with BE the lateral and third ventricles were dilated and the chiasma tic cistern was widened. The subarachnoid space was wider than the upp er limits in the control group, in the frontal region (4 mm), and the anterior interhemispheric (4 mm) and Sylvian (3 mm) fissures. The infr atentorial CSF compartments, the occipital subarachnoid space, the pos terior part of the interhemispheric fissure and, in most cases, the co rtical sulci were normal in size in children with BE. The majority wer e macrocephalic or had rapid head growth but there were also normoceph alic children with normal head growth. The size of the posterior fossa was within the normal range in all children with BE. Idiopathic BE is not uncommon in children up to about 3 years old who are healthy or h ave minimal neurological disturbance and is characterised by a specifi c pattern of widening of the supratentorial CSF compartments.