The Feasibility of Quantitative Assessment of Myocardial Perfusion Using Single Photon Emission Computed Tomography Imaging: Current Status and Future Challenges

Assessment of physiological ischemia is recently essential for the indication of coronary revascularization; such as percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) in patients with coronary artery disease. Moreover, quantitative assessment of myocardial flow reserve (MFR) is also getting important role for the evaluation of prognosis of heart diseases including non-ischemic cardiomyopathy.In the field of nuclear cardiology, positron emission tomography (PET) has been the only modality for the quantitative assessment of myocardial blood flow (MBF) and MFR. However, since availability of PET is much less than that of single photon emission computed tomography (SPECT) imaging, quantitative MBF/MFR assessment has been limited.Recently, high sensitivity gamma camera which equipped semiconductor detectors has been developed. It is reported that its image quality and spatial resolution are much superior to conventional Anger-type gamma camera. Moreover, since high sensitivity gamma camera consists of plural detectors, it can evaluate whole heart perfusion simultaneously. These advances make quantitative MBF/MFR analysis feasible like PET imaging. Although quantitative assessment with high sensitivity gamma camera is getting useful in clinical practice, several points; such as acquisition protocol and analysis methods, are immature compared to PET. Therefore, we have to investigate the solutions for these issues in near future for diagnostic certainty.