Cobalt-57 as a SPET tracer in the visualization of ischaemic brain damage in patients with middle cerebral artery stroke

In PET studies we have shown the usefulness of cobalt radionuclides for the visualization and quantification of ischaemic damage in stroke. In the present study, we explored Co-57(2+) as a SPET tracer. Uptake of radioactivity was estimated by using a cobalt enhancement ratio defined as the ratio of cobalt uptake in the affected region versus a similar volume in the non-affected contralateral side. Clinical status was assessed with the Orgogozo stroke score at the time of scanning and at least 60 days after admission. Nineteen patients (11 men, 8 women) with a middle cerebral artery stroke were examined with Co-57(2+) SPET 0-30 days after stroke onset. Our investigations show enhanced cobalt uptake in the infarcted brain tissue in patients with a major stroke and little clinical improvement. There was a significant correlation between the cobalt enhancement ratio and the Orgogozo score at the time of scanning and discharge. Our results suggest that Co-57(2+) SPET is suitable for determining the extent of (possibly calcium-mediated) damage in stroke and in the assessment of potential therapeutic interventions. ((C) 1998 Lippincoft-Raven Publishers).