Ventricular indices in infants with enlargement of the subarachnoid space

The aim of this study was to characterize ventricular measurements in children diagnosed with enlargement of the subarachnoid spaces (ESS) to determine ventricular morphology.

Children diagnosed with ESS were retrospectively identified between 2015 and 2023. Inclusion required a craniocortical width > 5 mm on neuroimaging. Demographic data and developmental outcomes were collected. Referrals to therapy services, including speech and language therapy, occupational therapy, or physiotherapy, were recorded. Ventricular size was quantified using the Evans Index (EI), bicaudate index (BCI), and cella media index (CMI) measured on axial T2-weighted MR images.

Of 101 children, 98 presented with macrocephaly; 3 were diagnosed incidentally through imaging. The mean age at referral was 9.0 ± 5.8 months, with a mean follow-up of 26.3 months. The median initial and final occipitofrontal circumference percentiles were 99.2 (IQR 5.6) and 99.6 (IQR 1.9), respectively. The mean craniocortical width was 9.92 mm. Ventricular indices were near or slightly above normal limits. In males, the mean EI, BCI, and CMI were 0.30 (range 0.22-0.38), 0.15 (range 0.09-0.21), and 4.43 (range 2.29-6.57), respectively. In females, the mean EI, BCI, and CMI were 0.29 (range 0.23-0.35), 0.15 (range 0.11-0.19), and 4.18 (range 2.38-5.98), respectively. No child required neurosurgical intervention. Developmental concerns prompted referrals to speech and language therapy in 56.4% of patients, physiotherapy in 16.8%, and occupational therapy in 13.9%; 4% had referrals across multiple domains.

This study presents one of the largest studies evaluating ventricular indices in children diagnosed with ESS. Despite mild ventriculomegaly and macrocephaly, no children underwent neurosurgical intervention. However, the association with therapy input supports a shift of focus to one of facilitating the children to achieve their developmental potential, best delivered by the pediatric and/or community service. Continued neurosurgical monitoring should be reserved for children in whom the diagnosis of ESS is not secure and concerns of raised intracranial pressure or hydrocephalus persist.