Late pathophysiological events after the production and subsequent removal of an intracerebral mass were investigated using a mechanical microballoon model to simulate intracerebral hemorrhage. Immediately following balloon inflation in the caudate nucleus of rats, there was a significant increase in intracranial pressure to 14 +/- 1 mm Hg (mean +/- standard error of the mean), accompanied by a reduction in cerebral blood flow (CBF) in the ipsilateral frontal cortex, as measured by the hydrogen-clearance technique. Carbon-14-iodoantipyrine autoradiography revealed a significant reduction in the CBF of the ipsilateral caudate nucleus 4 hours after balloon inflation: 31% of the caudate nucleus had a CBF of less than 20 ml X 100 gm-1 X min-1 compared to only 1% in the sham-treated control group (balloon insertion without inflation). The rats with an intracerebral mass exhibited a significant increase in the volume of ischemic damage in the ipsilateral caudate nucleus (17.1% of total volume) compared to only 1.7% in the sham-treated group; however, there was no evidence of cerebral edema. Ischemic damage and reduced CBF persisted for 4 hours after transient inflation of a microballoon in the caudate nucleus. This suggests that ischemic damage occurs at the time of formation of the lesion and is not prevented by its early removal.

The authors report a rare case of a cervical intraosseous schwannoma, which was diagnosed following an incidental history of trauma. This is the first case of an intraosseous schwannoma of the cervical vertebra that was diagnosed using magnetic resonance imaging. The authors discuss the radiological imaging, surgical procedure and review the relevant literature.

The aim of the study was to determine whether the extent of ischemia produced by an experimental space-occupying lesion changed between 5 minutes and 4 hours after the production of a lesion. In two groups of rats, a 50-microliter balloon was inflated in the right caudate nucleus. Cerebral blood flow (CBF) was determined by 14C-iodoantipyrine quantitative autoradiography, in Group 1 (n = 6) 5 minutes after inflation and in Group 2 (n = 6) 4 hours later. After 5 minutes of inflation, the mean blood flow in the caudate nucleus was reduced to 65% of the contralateral value and 11.5% of the ipsilateral caudate nucleus had a blood flow of below 25 ml/100 g/minute. After 4 hours of inflation, there was a greater fall in the mean CBF of the ipsilateral caudate nucleus to 30% of the contralateral value, and 38.9% of the ipsilateral caudate nucleus had a CBF of less than 25 ml/100 g/minute. The differences between the two groups were significant (mean CBF, P less than 0.01; CBF less than 25 ml/100 g/minute, P less than 0.02). The results show that the initial ischemic lesion produced by a spontaneous intracerebral space-occupying lesion does not remain static, but progresses with time and is significantly greater after 4 hours than after 5 minutes. Interventions that reduce the progression of ischemia may be beneficial in reducing the ultimate amount of ischemic brain damage.