Diagnosis:Venous infarct with hemorrhagic transformation secondary to venous thrombosis.
- 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.
1. W. Brant & C. Helms. Fundamentals of Diagnostic Radiology. Lippincott Williams & Wilkins. 2006.