Relationship between regional myocardial blood flow and the distribution of 99mTc-sestamibi in the presence of total coronary artery occlusion

Short-lived radioactive compounds are frequently used to measure body functions such as the dynamics of heart pumping and blood flow. Compounds containing technetium-99m (99m-Tc) have been developed, as they might be more useful for these imaging studies than isotopes such as thallium-201. To determine whether 99m-Tc-sestamibi, one such compound, is suitable for heart studies, its distribution in heart tissue under different conditions of blood flow was compared with that of thallium-201. The proportion of each compound distributed into heart tissue correlated with the level of blood flow, up to blood flow rates that were three times normal resting levels. The data show that 99m-Tc-labeled compounds provided good contrast between ischemic and non-ischemic heart regions, and this was maintained for at least 90 minutes. The study indicates that 99m-Tc-sestamibi should be at least as sensitive as thallium-201 in the detection of ischemic heart disease. (Consumer Summary produced by Reliance Medical Information, Inc.)