Bilateral Perisylvian Polymicrogyria

  • Etiology: abnormal cortical organization secondary to ischemic laminar necrosis of 5th cortical layer after 20 weeks gestation, may be caused by in-utero cytomegalovirus, ischemia, or genetic
  • Imaging: small haphazard gyri which can’t be named by textbook (gyri of lissencephaly can be named by textbook though simplified), too few sulci, anomalous venous drainage

Radiology Cases of Bilateral Perisylvian Polymicrogyria

MRI of perisylvian polymicrogyria
Axial T2 (above) and coronal T1 (below) MRI without contrast of the brain shows small haphazard appearing gyri and too few sulci present bilaterally, primarily in the sylvian fissures.
MRI of perisylvian polymicrogyria and open lip schizencephaly
Coronal T1 (above) and axial T2 MRI without contrast of the brain shows small haphazard appearing gyri and too few sulci present bilaterally, left greater than right, primarily in the sylvian fissures. There is also a cleft of gray matter with cerebrospinal fluid within extending from the cortex to the posterior aspect of the left lateral ventricle.