Pseudo-subarachnoid hemorrhage

Case contributed by Mohamed Mahmoud Elthokapy


Post cardiac arrest infant with prolonged downtime at the scene. Maintained on inotropic support and mechanical ventilation.

Patient Data

Age: 12 month
Gender: Male

CT without contrast

  • significant generalized low attenuation of the entire brain parenchyma and to less extent cerebellum (density of cerebellum is greater than cerebral hemispheres => reversal sign
  • evidence of diffuse cerebral edema with effacement of the grey-white matter borders and marked effacement of the brain sulci as well as major cisterns 
  • attenuated (non visualized) ventricular system with no midline shift
  • associated hyper-density is noted within the cisterns giving the appearance of pseudo-subarachnoid hemorrhage due to effacement of the subarachnoid space surrounding blood vessels. 
  • grey-white matter interface has been lost as well

CT angiography (with contrast)


CT angiography demonstrates faint/poor opacification of the cortical cerebral arteries distal to the middle cerebral arteries and internal cerebral veins, however, fair opacification of carotid and vertebral arteries.

Case Discussion

A typical case of pseudo-subarachnoid hemorrhage in an infant with post cardiac arrest with resultant hyoxic/anoxic cerebral insult. Consequent diffuse brain edema and swelling where there is global decrease in parenchymal attenuation. 

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