MRI of these aberrations of cortical development

1. 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

2. - 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