Hypodense bubbles in acute extradural haematomas following venous sinus tear. A CT scan appearance

Between January 1982 and December 1989, 12 patients with 13 acute extradural haematomas as a result of injury involving the venous sinuses were treated by the first author. The CT scan appearances in 6 cases were remarkable in that there were large bubbles of low density in the hyperdense haematomas and liquid blood was found during the operation. The possible underlying pathophysiological changes that gave rise to this appearance are discussed. The CT scan appearance and the proximity of the clot to the venous sinuses should alert the neurosurgeon to the high probabilities of venous sinus tear such that proper treatment can be offered.