FIGURE 3. Perfusion study of single photon emission computed tomography (CT) before and after balloon occlusion test for the right internal carotid artery (ICA) in the same day. The baseline scan (A) was taken by injecting 20 mCi of technetium-99m-ethyl cysteinate diethylester (99mTc-ECD) before the angiogram and 40 mCi of 99mTc-ECD was given at 15 minutes in the balloon occlusion of the right ICA (B). At the post-occlusion scan, aggravation of perfusion asymmetry on the right frontal cortex was seen, especially in the middle and posterior frontal cortex (arrows) and about 21% of perfusion reduction was measured. The hypoperfusion area in the right frontal was matched with the infarct zone in the brain CT.
