Pachygyria, Polymicrogyria
* Pachygyria: Broad, flattened gyri; thickened cortex Polymicrogyria: Many small gyri Pachygyria and polygyria often occur together
* MR Findings
- Pachygyria Flatter, broader shape to gyri than normal, thick cortex
- Polymicrogyria Initially irregular cortex progressing to too many infoldings of cerebral surface. Fine sawtooth or zigzag appearance to cortex
- Lissencephaly Type 1 “Smooth” brain. Absence or diminished number of cortical sulci throughout cerebral hemispheres with thick cortex. Hourglass or figure 8 shape of cerebral hemispheres. Normocephalic to microcephalic. Spectral continuum with polymicrogyria-pachygyria.
* Most often seen in association with other brain abnormalities :
- Mild ventriculomegaly Nodular ventricular walls suggest heterotopic gray matter.
- Agenesis of corpus callosum Or other brain malformation associated with absent cavum septi pellucidi.
- Intracranial cyst
- Cerebellar hypoplasia
* Differential Diagnosis
-Cobblestone lissencephaly = Type 2 Lissencephaly. Fine nodular brain surface,Pebbly" surface of brain, Disorganized unlayered cortex, many neurons move too far into subpial space → cobblestone complex. Associated ocular findings in Walker-Warburg syndrome, cerebellar abnormalities, congenital muscular dystrophy.
* Etiology Metabolic disorders. Infection: CMV, toxoplasmosis, parvovirus Ischemia, teratogens Genetics: gene mutations.
* PolyMicroGyria is probably common endpoint of variety of aberrations of cortical development.
Courtesy of: 1- Anne Kennedy, MD, in Statdx: Obstetrics > Diagnosis > Brain > Cortical Developmental Anomalies : Pachygyria, Polymicrogyria.
https://my.statdx.com/document/pachygyria-polymicrogyria/2a6bef9e-1ff2-459b-b79f-e0a5900d2f18
2- Blaise V. Jones, MD, in Statdx: Brain > Diagnosis > Pathology-based Diagnoses > Congenital Malformations > Malformations of Cortical Development : Lissencephaly.
https://my.statdx.com/document/lissencephaly/4cacfbaf-e5ca-48bf-8f4e-a459f22c8457