Major advances in single-photon emission computed tomography perfusion imaging

Major advances in single-photon emission computed tomography (SPECT) myocardial perfusion imaging have been realized with the introduction of state-of-the-art imaging equipment and radiopharmaceuticals. Gated tomographic myocardial perfusion imaging with technetium-99m (Tc-99m)-labeled radiopharmaceuticals provides a combined evaluation of both myocardial perfusion and function. Left ventricular ejection fraction can be measured accurately from the gated SPECT images. Recently, hardware and software have been introduced, which minimize the effect of soft tissue attenuation, thereby improving test specificity in the diagnosis of coronary artery disease. Myocardial viability may be assessed with the use of rest/delayed thallium-201 SPECT or F-18 fluorodeoxyglucose SPECT with modified scintillation camera collimation and electronics, or coincidence detection. Imaging patients to assess myocardial infarction or resting ischemia in the emergency department has expedited patient care and improved cost effectiveness. Teleradiography has also facilitated the interpretation of studies performed in the emergency department and at remote facilities, likewise improving cost-effectiveness.