Abstract
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Objectives The study was aimed to compare the diagnostic performance of SPECT radiotracer 99mTc-Sestamibi & 13N-NH3 PET in assessment of myocardial viability in matched patient populations.
Methods Two hundred and eight patients with known CAD (M: F=200:8) were referred to our department for assessment of myocardial viability. Eighty two patients underwent 13N-NH3 & 18F-FDG (Group A) and 126 patients were evaluated with 99mTc-Sestamibi & 18F-FDG (Group B). SPECT images were acquired on dual head SPECT-CT and 13N-NH3 & 18F-FDG PET images were acquired on dedicated PET/CT scanner. The studies were analysed using Emory Cardiac Toolbox (20-segment model).
Results The mean age of the patients was 54.3±8.5 years. There was no significant difference in the distribution of confounding factors namely age, sex, diabetes, smoking, obesity between the two groups (p=0.646; p=1.000; p=0.522; p=0.385; p=0.326). All patients had coronary angiography and findings in relation to single, double and triple vessel involvement were comparable in both the groups (p=0.133). A total of 4160 segments (Group A:1640; Group B:2520) were analysed. Hibernating myocardium was detected in 147 segments in Group A compared to 186 segments in Group B (p=0.619). Similarly no statistically significant difference was noted in number of mixed segments (mixed lesion of scarred and viable myocardium) and scarred myocardium in Group A & B, 52 vs. 101 (p=0.533) and 276 vs. 460 segments(p=0.439) respectively. Also no significant difference was noted between the groups based on coronary artery distribution (Table-1).
Conclusions SPECT imaging using 99mTc-Sestamibi has comparable sensitivity to 13N-NH3 PET in detection of pathological myocardium (hibernating, mixed lesion and scarred). Thus, SPECT radiotracer in conjunction with 18F-FDG PET can be used for assessment of myocardial viability