Early Versus Standard Late Image Acquisition in Adenosine Myocardial Perfusion Imaging

Objectives: Transient postischemic left ventricle (LV) dysfunction due to myocardial stunning in patients with ischemic heart disease can be missed by conventional gated single-photon emission computed tomography, which advises a 45-min delay after pharmacological stress. Early imaging may detect poststress stunning in ischemic myocardium more effectively. This study aimed to investigate whether early imaging (15 min poststress) detects parameters of stress-induced LV dysfunction better than standard late imaging (45 min poststress). Material and Methods: A prospective study was conducted with 100 patients undergoing 1-day rest-stress pharmacological myocardial perfusion imaging. Early poststress images were taken at 15 min (T15) and late poststress images at 45 min (T45). Image quality, heart/lung ratios, perfusion scores (Summed Stress Score [SSS], Summed Difference Score [SDS]), and functional parameters (EF, end-diastolic volume [EDV], end-systolic volume [ESV], transient ischemic dilatation [TID]) were evaluated and compared. An SDS ≥ 4 defined an abnormal perfusion response. Results: Ischemia was detected in 38% of patients at T15, compared to 34% at T45 (P < 0.001). No significant differences were found in SSS or SDS between T15 and T45. Image quality improved over time, with 90% of T45 images rated as excellent, compared to 64% at T15. The heart/lung ratio was significantly higher at T45 than at T15 (P < 0.001). No significant differences in EF, EDV, or ESV were observed. Ischemic patients showed a trend toward statistical significance in ΔEF, suggesting potential LVEF changes. Conclusion: Early T15 imaging detects reversible perfusion defects more effectively, offering potential diagnostic advantages over T45, while maintaining similar image quality and diagnostic precision. Although EF changes were not statistically significant, trends suggest myocardial stunning and subtle stress responses.