Dipyridamole-loading 99mTc-tetrofosmin myocardial scintigraphy was performed for patients with coronary artery disease who underwent percutaneous transluminal coronary angioplasty (PTCA) in order to examine whether SPECT imaging prior to treatment is useful for the determination of prognosis after coronary intervention. Thirty-six patients including 9 with angina pectoris (AP), 22 with old myocardial infarction (OMI) and 5 OMI with AP were underwent dipyridamole-loading 99mTc-tetrofosmin myocardial SPECT before and after coronary intervention. The length of follow-up was 185 +/- 107 days after PTCA. Improvement of myocardial uptake was observed on myocardial SPECT in all cases with AP. Improvement of the myocardial uptake was observed 50% (4/8) of patients with OMI who had no myocardial viability. It was suggested that the improvement of myocardial uptake after PTCA was due to incomplete fill-in in cases with AP and that the presence of fill-in was important for level of fill-in in patients with AP. The improvement of myocardial uptake in the scar tissue in patients with OMI contributed to the hibernating myocardium. We concluded that correct detection of hibernating myocardium was difficult despite the superior imaging capability of 99mTc-tetrofosmin myocardial SPECT.