Barkovich classification of agenesis of the corpus callosum with interhemispheric cyst

The Barkovich classification of agenesis of the corpus callosum with interhemispheric cyst divides interhemispheric cysts that are diagnosed in individuals with concurrent agenesis of the corpus callosum into two types based on the presence or absence of communication with the ventricular system. These are then divided into further subtypes based on additional features.

Classification

Type 1

Type 1 cysts communicate with the lateral or third ventricles and are therefore filled with CSF. They are unilocular.

• type 1a: communicating hydrocephalus

  • communicate with lateral ventricles

  • associated with

    • hydrocephalus

    • macrocephaly

    • Dandy-Walker malformations

• type 1b: diencephalic anomaly with hydrocephalus

  • communicates with the third ventricle

  • third ventricular outflow obstruction

  • associated with

    • macrocephaly

    • diencephalic malformations

• type 1c: cerebral hypoplasia

  • communicates with lateral and/or third ventricles

  • associated with

    • microcephaly

    • cerebral hypoplasia or cerebral dysplasia

Type 2

Type 2 cysts are loculated without visible communication with the ventricular system. They may be unilocular or multilocular and have variable signal intensity.

• type 2a: isolated abnormality

  • isointense to CSF

  • multilocular

  • associated with

    • macrocephaly if cyst is large

• type 2b: Aicardi syndrome

  • hyperattenuating on CT, hyperintense on T1 weighted imaging

  • multilocular

  • associated with other features of Aicardi syndrome

• type 2c: subcortical heterotopia

  • isointense to CSF

  • multilocular

  • associated with other features of subcortical heterotopia

• type 2d: arachnoid cyst

  • isointense to CSF

  • unilocular