Clinical application of cardiac SPECT/CT fusion image with MIBI/BMIPP dual isotope imaging in patients with severe myocardial ischemia

Objectives 123-I- BMIPP imaging can estimate myocardial ischemia at rest in patients with severe myocardial ischemia. Recently, cardiac SPECT/CT Fusion imaging by CardIQ Fusion (GE Healthcare) is available for ischemic heart disease. The purpose of this study is to clarify the usefulness of SPECT/CT Fusion image using 123I-BMIPP for patients with severe myocardial ischemia.

Methods Consecutive 41 patients (31 men and 10 women; mean age 66 years) clinically diagnosed with severe myocardial ischemia were included in this study. The kinds of diagnosis were unstable angina (n = 9) and ischemic cardiomyopathy (n = 32). All patients underwent dual isotope SPECT using Tc-99m-sestamibi and I-123-BMIPP, and CT coronary angiography (CTCA) by 64-slice CT. Interval of both studies was within 3 months. Two experienced nuclear cardiologists analyzed the SPECT image only, non-fused SPECT and CTCA images (side-by-side analysis), SPECT/CT Fusion image with regard to culprit coronary artery. Moreover, the rate of non-evaluable coronary segments by CTCA because of insufficient image quality due to dense calcification and hemodynamic significance of those lesions are evaluated.

Results SPECT image revealed defect in all patients. Perfusion/Metabolism mismatch is detected in 37 patients. A stenosis ≥ 50% was found in 302/695 segments (43%), 41 patients (100%) on CTCA. The fused SPECT/CT interpretation provided added information with regard to 7 cases (17%) and allowed alternation of a relevant lesion in significantly more segments than the side-by-side analysis (P < 0.001). Hemodynamic significance of densely calcified coronary lesion was showed in 10/16 cases (63%), 13/54segments (24%).

Conclusions Cardiac SPECT/CT fusion imaging provides additional information about hemodynamic relevance lesion interpretation by allowing exact allocation of accumulation defects to its subtending coronary artery even in patients with severe myocardial ischemia and dense coronary calcification