How frequent is polymicrogyria bilateral?
Bilateral involvement is common seen in up to 60% of cases (not in this case).
What is the imaging test of choice to identify polymicrogyria. What do you look for?
MRI is the modality of choice. The cortex appears thicker than normal. The grey-white junction is often the best location to identify the 'bumpy' contour which on thicker slices may manifest as blurring.
MRI of the brain demonstrates an extensive area of developmental malformation which involves the posterosuperior margins of the left Sylvan fissure. This is characterised by abnormal cortical thickening and a nodular surface and grey-white matter interface. No cleft or grey matter heterotopia noted. Septum pellucidum is present.