Background: We wished to determine the ability of radiolabeled annexin V to concentrate at sites of ischemic injury in patients with acute cerebral stroke. Secondly, we sought to correlate annexin V imaging in these patients with the degree of blood-brain barrier (BBB) breakdown.
Methods: Twelve patients with acute stroke had a complete neurological examination, including the National Institutes of Health (NIH) stroke scale and the Glasgow Coma Score (GCS). A non-contrast CT scan was performed on all patients. A SPECT of the brain was obtained 2 h after injection of annexin V. The integrity of the BBB was evaluated in seven patients using Tc-99m-DTPA brain SPECT.
Results: All patients had an infarct in the MCA territory. Eight patients had abnormal increased annexin V activity, which was more common in patients with cortical strokes (P = 0.01). The concentration of annexin had no correlation to the volume of stroke, but it was significantly and inversely related to the GCS on admission (r = -0.7, P = 0.02). Foci of apoptosis were noted contralateral to the affected hemisphere as well. All seven patients who underwent DTPA SPECT showed breakdown of the BBB. DTPA uptake was significantly and positively associated with NIH score (r = 0.80, P = 0.01) and inversely associated with GCS (r = -0.89, P = -0.03).
Conclusion: This study shows that it is possible to identify in vivo regions of ischemic neuronal injury using radiolabeled annexin V in patients with acute stroke. Annexin imaging can play a major role in the selection of therapy in the initial period following stroke in adults.