Xenon enhancement in tumours and infarcts.

Computed topography (CT) before and during xenon enhancement and computer subtraction has been performed in 11 patients with intracerebral tumours and 7 with ischaemic lesions. The amount of xenon uptake was expressed where possible as a percentage of that in the corresponding region of the contralateral apparently normal hemisphere. The amount of xenon uptake did not appear to be specific for any particular tumour histology. The margins of tumours were better defined during enhancement, but not to a degree which affected management; large cysts did not enhance and were well demonstrated. Cavities due to mature infarcts did not enhance and the central parts of most large recent infarcts showed markedly diminished enhancement. In recent infarcts delayed xenon uptake at the periphery and sometimes throughout the lesion reflects diminished perfusion of potentially viable tissue. One patient with an ischaemic parietal lesion in which xenon uptake was normal made a complete clinical recovery.