Case of the Month: April 2007

Diagnosis:

Venous infarct with hemorrhagic transformation secondary to venous thrombosis.

Discussion:

  • Uncommon
  • Presentation: headache, sudden focal deficits & often seizures.
  • Risk factors: hypercoagulable states (birth control pills), pregnancy, infection (spread from contiguous scalp, face, middle ear or sinus), dehydration, meningitis & direct invasion by tumor.
  • Pathophysiology: Even with an intact arterial supply, blockage of the venous outflow leads to stasis, deoxygenation of blood & neuronal death. Continued perfusion into damaged, occluded vessels frequently leads to hemorrhage.
    • Most commonly affected venous sinuses: lateral transverse, superior sagittal & cavernous sinus.
  • Major imaging findings:
    • Hemorrhagic infarction in deep cortical or subcortical regions that may spare overlying cortex unlike classical wedge shaped cortical infarcts seen in arterial occlusion.
    • Does not conform to known arterial territory.
    • CT: may see "emtpy delta" sign which is usually present 1-4 weeks after sinus occlusion.
    • Combination of spin-echo MR and MR venography probably provides the best imaging evaluation for dural sinus occlusion.
References:

1. W. Brant & C. Helms. Fundamentals of Diagnostic Radiology. Lippincott Williams & Wilkins. 2006.

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