TOWARD CONSENSUS ON QUANTITATIVE ASSESSMENT OF MEDICAL IMAGING-SYSTEMS

Consensus has been developing over the past few decades on a number of measurements required for the laboratory assessment of medical imagin g modalities. Nevertheless, understanding of the connection between th ese measurements and human observer performance in a broad range of ta sks remains far from complete. Focusing primarily on projection radiog raphy to provide concrete examples, this overview indicates areas in w hich consensus on methodology for physical image-quality measurement h as been established. Concepts such as ''noise equivalent quanta'' (NEQ ) and ''detective quantum efficiency'' (DQE) have been found useful fo r normalizing physical measurements on an absolute scale and for relat ing those measurements to the decision performance of a hypothetical ' 'ideal observer'' that effectively performs decision tasks from the im age data. The connection between ideal observer performance and human performance, as determined by receiver operating characteristic (ROC) analysis, remains to be understood for many clinically relevant tasks.