Quantitative Assessment of Regional Myocardial Flow Reserve Using Tc-99m-Sestamibi Imaging

Comparison With Results of O-15 Water PET

Abstract

Background The aims of this study were to develop a method for quantitative estimation of the myocardial blood flow index (MBFI) and myocardial flow reserve (MFR) of the whole left ventricle using ^99mtechnetium (Tc-99m)-sestamibi imaging. Methods and Results Twenty-two patients with suspected coronary artery disease and 7 controls underwent both Tc-99m-sestamibi imaging and O-15 water positron emission tomography (PET). The global MBFI was calculated on the basis of the microsphere model from the ratio of the myocardial count to the area under the time - activity curve on the aortic arch. The regional MBFI was calculated from the relative distributions of Tc-99m-sestamibi uptake values. The regional MBFI and MFR (Tc-MFR) obtained using single-photon emission computed tomography were compared with the myocardial blood flow (MBF) and MFR (PET-MFR) obtained using PET as the gold standard. Regional MBFI significantly correlated with the MBF obtained using PET. Regional Tc-MFR also correlated with the regional PET-MFR, with some underestimation. Conclusion These results indicate that regional MBF and MFR may be estimated by dynamic Tc-99m-sestamibi imaging and can be used for the early detection and estimation of the functional severity of coronary lesions without the need for a PET camera. (Circ J 2005; 69: 188 - 193)