Analysing The Prognostic Parameters For CAD In Stress-rest GSPECT Myocardial Perfusion Imaging

Objective:To evaluate the relationship between transient ischemia dilation, increased lung uptake and perfusion defects and left ventricular blood store, investigating the relationship between transient ischemia dilation and lung/heart ratio after stress 99mTc-MIBI myocardial perfusion imaging and providing further insight into the mechanism of cavity dilation.Methods:Stress and rest 99mTc-MIBI Gated SPECT were performed in 170 patients with suspect coronary artery disease in the first hospital of Shan Xi medical university between January 2004 and December 2008.67 female and 103 male patients were included in this study, with an average age of 51.8±12.7(34-58) years. Semiquantitative summed stress scores (SSS) were determined using a 17-segment,5 point model (0=normal, 1=equivocal,2=moderate, and 3=severe reduction of radioisotope uptake; 4=absence of detectable tracer uptake in a segment), which was calculated by summing all regions where radial plot activity fell below the normal limits; The left cardiac function and transient ischemia dilation ratio(TID ratio) were processed automatically by the ECToolbox software. Lung/heart ratio(LHR) was calculated by left lung ROI average pixel counts/myocardium ROI average pixel counts. In addition, the stress-induced volume ratio(SIVR), defined as stress-to-rest ratio(end-systolic volume×5+end-diastolic volume), was calculated. Patients were divided into four groups according to the SSS:the G1(SSS<3), G2(4≤SSS≤8), G3(9≤SSS≤13) and G4(SSS≥14); According to the△LVEF (stress LVEF-resting LVEF), Patients were divided into two groups, groupⅠ(△LVEF≥0) and groupⅡ(△LVEF＜0).Results:1 The TID ratio, SIVR(5), sLHR and rLHR were compared respectively in different groups. The results showed that:in G4, TID ratio, SIVR(5), sLHR and rLHR were significantly greater than the other three groups(p<0.05); Compared sLHR and rLHR in each group, we found that there were significantly difference in G3 and G4(0.32±0.08 and 0.31±0.04,0.35±0.07 and 0.33±0.06, p<0.05).2.①In groupⅠ, Stress and rest EDV were 81.3±29.1,85.7±28.6; ESV were 29.4±18.8,35.7±20.5. There were significant differences between stress EDV and rest EDV; As ESV, the significant differences was still existed between tress and rest (p<0.001). In groupⅡ, there were no significant differences between stress EDV and rest EDV (81.7±23.7 and 81.8±23.7,p>0.05), but stress ESV was significantly expanded compared with rest ESV (33.3±15.5 and 29.6±14.1, p＜0.001)。②The TID ratio(1.04±0.14 and 0.95±0.12), SIVR(5)(1.09±0.21 and 0.86±0.13), sLHR (0.34±0.09 and 0.31±0.06) and rLHR(0.32±0.07 and 0.31±0.05) were obviously greater in groupⅡthan group I (p<0.05). In addition, Comparing sLHR and rLHR in each groups, A visible difference was seen in groupⅡ(0.34±0.09 and 0.32±0.07, p<0.05), whereas there was no significant difference in groupⅠ3.There was a weak relationship between TID ratio and SIVR(5) (r=0.391,p＜0.001); No relationship was seen between TID ratio and sLHR (r=0.004, p>0.996)。Conclusion:1. TID ratio and SIVR(5) are significantly greater in patients with severe perfusion defects, it suggested that both of indicators are associated with the severe and extensive CAD.2. Increased lung uptake (especially post stress increased lung uptake) is related to perfusion defects and left ventricular blood store.3. TID and post stress increased lung uptake have a closely relationship with myocardial reserves function, And stress-induced left ventricular dysfunction is the possible reason for TID and post stress increased lung uptake.4. There was a weak relationship between TID ratio and SIVR(5). No relationship was seen between TID ratio and sLHR.