Computed tomography in spontaneous intracerebral haematomas.

The typical computed tomographic (CT) features of a recent intracerebral haematoma are a homogenous region of increased attenuation surrounded by a well demarcated relatively narrow low attenuation ring (LAR). The pathology of the LAR is controversial, but it corresponds well with a zone of ischaemic necrosis which is observed around most intracerebral haematomas exmined at autopsy. Observations are made on spontaneous intracerebral haematomas and on blood samples which confirm that extravasated blood clot undergoes a variable degree of retraction which is completed within six hours. This suggests that the LAR in recent haematoma is due to damage caused by the greater volume of the precontracted haemorrhage on the surrounding brain. CT abnormalities in intracerebral haematomas were studied; features which were useful in distinguishing spontaneous haematomas and those which affected prognosis are discussed.