Benign Enlargement of the Subarachnoid Space

  • Etiology: due to immature + inefficient arachnoid villi, causing temporary communicating hydrocephalus
  • Imaging: subarachnoid space relatively larger in infants < 2 years old, subarachnoid vessels cross the space
  • Clinical: presents with macrocephaly, resolves on its own by 2-3 years

Radiology Cases of Benign Enlargement of the Subarachnoid Space

MRI of benign enlargement of the subarachnoid space
Axial T2 MRI without contrast of the brain shows a diffusely enlarged subarachnoid space being crossed by subarachnoid vessels. The ventricular system is normal in size.