Subarachnoid spaces in infants and young children.

In computed tomography of young children, the frontal subarachnoid spaces were sometimes noted to be prominent in scans which were otherwise normal. These apparently enlarged spaces raise the suspicion of possible subdural hygromas. The objective of this study is to show the trend and variability of the intracranial subarachnoid spaces, especially the frontal subarachnoid spaces with age in children. Computed tomographic scans of 39 children up to five years of age with normal head scans were assessed for sizes of the subarachnoid spaces which were subjectively graded from I to V. Grade I is not visible while grade V is borderline enlargement. The sizes of the subarachnoid spaces were found to be more variable in those below the age of two years, with a tendency to be larger compared to older children. Based on these observations, prominent subarachnoid spaces in those below the age of two years should be considered a normal variant. A diagnosis of subdural hygroma must, therefore, be made with caution.