PNR Head 07

12 week old with seizure

Normally, you can trace the demarcation between cortical gray matter and subcortical white matter with an imaginary pencil (compare to this normal example). 

If you cannot clearly trace this line, there could be 2 reasons: 

(1) In younger pediatric patients this could be due to the myelination status (refer to these normal CTs in various ages)

(2) In older pediatric patients you have to be concerned about processes such as hypoxia, ischemia, encephalitis. 

Here, given extent and symmetry, the loss of differentiation of gray and white matter is highly concerning for hypoxic ischemic encephalopathy (HIE).

This case was missed twice, on CT and on MR.