Very early and standard Tc-99m ethyl cysteinate dimer SPECT imaging in a patient with reperfusion hyperemia after acute cerebral embolism.

Abstract

It has been reported that Tc-99m ethyl cysteinate dimer (ECD) SPECT imaging may not show reperfusion hyperemia in patients with subacute stroke. The authors describe a patient with embolic middle cerebral artery occlusion who was examined using xenon-133 and dynamic and standard Tc-99m ECD SPECT immediately after early recanalization. Standard Tc-99m ECD SPECT images revealed hypoactivity in the ipsilateral middle cerebral artery territory. In contrast, the dynamic Tc-99m ECD SPECT images from the first scan (very early images acquired 36 seconds after injection) showed hyperactivity in the same region and provided imaging contrast comparable to what would be obtained with xenon-133 tomography. Hemorrhagic transformation later developed in this region. These results indicate that images from very early dynamic Tc-99m ECD SPECT of areas with irreversible changes produced by acute stroke can reveal reflow hyperemia that standard Tc-99m ECD SPECT images fail to show.