A method includes determining a low contrast detectability of a scan and generating an image quality index based on the determined low contrast detectability. Another method includes identifying an image quality index of interest, identifying an acquisition and/or reconstruction parameter based on the image quality index and a pre-determined mapping between image quality indexes and acquisition parameter and reconstruction parameters, and displaying the identified acquisition and/or the reconstruction parameter. A system (100) includes a metric determiner (122) that determines a first image quality index for a scan based on at least one of a low contrast detectability of the scan or a project domain noise of the scan, and/or a parameter recommender (126) that recommends at least one of an acquisition or a reconstruction parameter for a scan based on a second image quality index, and a display (114) that visually presents the first or second image quality index.