
Neuroradiology
Teaching File
There
are bilateral crescent shaped extraaxial fluid collections, compatible
with subdural hematomas. Each collection has a fluid-fluid level.
The high attenuation dependent portion represents acute blood
from repeated hemorrhage superimposed on chronic hemorrhage (low
attenuation). The larger left subdural hematoma has mass effect
with effacement of the left lateral ventricle.
A subdural hematoma is caused be stretching and tearing of the bridging cortical veins which cross the subdural space to drain into the adjacent dural sinus. Ten to thirty percent have repeat hemorrhage, secondary to rupture of stretched cortical veins as they cross the enlarged fluid filled subdural space or from the vascularized neomembrane.
Case prepared by Steven Lee, M.D. and Anthony L. Alcantara,
M.D.