Abstract
^99mTc-Hexakis-2-Methoxy Isobutyl Isonitrile(MIBI)redistribution and washout in myocardium were studied in 28 patients with angina pectories(AP group)and 18 patients with myocardial infarctions(MI group). Single photon emission computed tomography(SPECT)was carried out 1 hour and 3 hour after the injection of 600MBq(10MBq/kg)of MIBI at rest. SPECT images were divided into 12 segments and quantitative analyzed by normalized washout rate(NWR). NWR=(RWR-mWR)/σ……(1) RWR : regional washout rate, mWR : mean washout rate, σ : standard deviation NWR<-1 indicates redistribution, NWR>1 indicates washout Segment analysis=(NS/TNS)×100(%)……(2) NS : Number of segments with NWR<-1 or NWR>1, TNS : Total number of segments Patient's analysis=(NP/TNP)×100(%)……(3) NP : Number of patients having segments with NWR<-1 or NWR>1, TNP : Total number of patients In the AP group, MIBI redistribution was observed at a higher frequency than in the MI group. (segment analysis=10.4% in the AP group, 5.5% in the MI group. patient's analysis=79% in the AP group, 56% in the MI group.) In the MI group, MIBI washout was observed higher frequency than the AP group. (segment analysis=10.2% in the MI group, 8.0% in the AP group. patient's analysis=89% in the MI group, 71% in the AP group.) These data showed MIBI redistribution and washout in myocardium may reflect myocardial risk for ischemia.
