Walif Chbeir Radiology Notes

Edited on January, 09, 2017

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