[Value of stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI]

A total of 110 patients suspected with CAD who had symptoms or ECG abnormalities were enrolled in the stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI. All the patients underwent symptom-limited exercise testing and 250 MBq of MIBI was injected at peak exercise. Exercise perfusion SPECT images were reviewed by two trained doctors to classify into three groups; normal, equivocal and abnormal. Patients with normal stress image (n = 53) did not receive the resting study. On the other hand, those with equivocal (n = 20) and abnormal (n = 37) stress images performed resting study, including gated SPECT. Of 20 equivocal cases, 16 patients showed unchanged resting perfusion. All of these had normal wall motion. The remaining 4 patients showed improved resting perfusion, indicating presence of myocardial ischemia. Of 37 abnormal cases, 12 patients showed improved resting perfusion, whereas 25 patients showed unchanged resting perfusion. Cardiac events were more often observed in abnormal cases, especially those associated with myocardial ischemia, while good prognosis was obtained in normal cases. Values of this protocol are (1) Patients with normal stress images need no resting study. (2) All the procedure can be completed in one day. (3) Both cardiac function and perfusion can be obtained with gated SPECT. These data indicates that this protocol is valuable for screening patients suspected with CAD.