The Evaluation of Left Ventricle Ischemic Extent in Highly Suspected Cardiovascular Disease Patients by ^99mTc-Sestamibi Dynamic SPECT/CT

Objectives: Coronary artery disease (CAD) is the 2nd cause of death due to atherosclerosis in Taiwan. Quantitative coronary blood flow was collected by dynamic single-photon emission computed tomography/computed tomography (Dynamic SPECT/CT) that may play an important role in the diagnosis in triple vessel disease, post-infarction myocardium, and cardiomyopathy. However, few studies revealed left ventricle (LV) ischemic extent of CAD diagnosis by Dynamic SPECT/CT. The goal of this study was to investigate LV ischemic extent by Dynamic SPECT/CT that patients was highly suspected CAD referred by cardiologist.

Methods: 181 patients were presented typical symptoms and highly suspected CAD and referred by cardiologists. Patients underwent ^Tc-99mMIBI (MIBI) Dynamic SPECT/CT survey before PCI by rest/dipyridomale-stress MIBI on one-day protocol. It was performed on a dedicated Siemens Symbia-T2 SPECT system. At rest, a 13 mCi MIBI injection was followed by low dose CT for attenuation correlation. After 3 hours, dipyridamole was infused intravenously at a rate of 0.56 mg/kg. The second dose of 30 mCi MIBI injection was given after terminating the dipyridamole infusion; the data was then analyzed by MyoFloQ software. Semi-quantitative MIBI myocardial perfusion imaging (MPI) was also analyzed. Statistical analysis was performed with commercially available soft ware (SPSS) and P <0.05 was considered statistically significant.

Results: Dynamic SPECT/CT has higher sensitivity (88%), specificity (96%), and accuracy (94%) than semi-quantitative MIBI MPI (more than ~10%) in our patients. After analysis indicated that the LV ischemic extent is about 5% which can yield positive PCI results (>70% stenosis in coronary arteries); another results of the moderate abnormal extent of LV is at least 15.3% that can yield positive PCI results. Interesting, the combination of moderate abnormal extent and ischemia extent of LV is at least 27.25% and may indicated positive PCI results.

Conclusions: This study revealed strongly association between Dynamic SPECT/CT and PCI results in highly suspected CAD patients. Dynamic SPECT has greater sensitivity, specificity, and accuracy as compared with semi-quantitative MIBI MPI. We conclude significant LV ischemic or LV moderate abnormal extent in Dynamic SPECT/CT might yield a potential value for predicting possible positive PCI results in highly suspected CAD patients who will undergo PCI intervention.