Walif Chbeir Radiology Notes
Edited on January, 09, 2017
Pachygyria: Broad, flattened gyri; thickened cortex
Polymicrogyria: Many small gyri
Pachygyria and polygyria often occur together
* MR Findings
Flatter, broader shape to gyri than normal, thick cortex
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.
Infection: CMV, toxoplasmosis, parvovirus
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.
2- Blaise V. Jones, MD, in Statdx: Brain > Diagnosis > Pathology-based Diagnoses > Congenital Malformations > Malformations of Cortical Development : Lissencephaly.