Overall repeatability and accuracy of myocardial blood flow measurements depend on the quality of the image data, the proper use of the quantitative software, and the training of clinical staff. Unlike most imaging tests, absolute blood flow measurements have the potential to provide accurate information beyond what is seen visually. This additive information has been shown to help identify multivessel disease, balanced ischemia, true normal studies, and quality control problems that may not be visible in the relative perfusion pattern. Absolute blood flow and flow reserve measurements have been shown to be useful and reproducible on a wide array of imaging systems, radiotracer delivery systems, and software approaches. Regardless of the technology or technique, these benefits can only be achieved when the quality of the study is sufficient and the clinical staff is properly trained on its implementation.