title: Anthropomorphic model observer performance in three-dimensional detection task for low-contrast computed tomography.
abstract: X-ray medical imaging is increasingly becoming three-dimensional (3-D). The dose to the population and its management are of special concern in computed tomography (CT). Task-based methods with model observers to assess the dose-image quality trade-off are promising tools, but they still need to be validated for real volumetric images. The purpose of the present work is to evaluate anthropomorphic model observers in 3-D detection tasks for low-contrast CT images. We scanned a low-contrast phantom containing four types of signals at three dose levels and used two reconstruction algorithms. We implemented a multislice model observer based on the channelized Hotelling observer (msCHO) with anthropomorphic channels and investigated different internal noise methods. We found a good correlation for all tested model observers. These results suggest that the msCHO can be used as a relevant task-based method to evaluate low-contrast detection for CT and optimize scan protocols to lower dose in an efficient way.
authors.affiliation: Lausanne University Hospital , Institute of Radiation Physics, Lausanne, Switzerland.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ba
authors.affiliation: University of California Santa Barbara , Department of Psychological and Brain Sciences, Santa Barbara, California 93106, United States.
authors.forename: Miguel P
authors.initials: MP
authors.lastname: Eckstein
authors.affiliation: Lausanne University Hospital , Institute of Radiation Physics, Lausanne, Switzerland.
authors.forename: Damien
authors.initials: D
authors.lastname: Racine
authors.affiliation: Lausanne University Hospital , Institute of Radiation Physics, Lausanne, Switzerland.
authors.forename: Julien G
authors.initials: JG
authors.lastname: Ott
authors.affiliation: Lausanne University Hospital , Institute of Radiation Physics, Lausanne, Switzerland.
authors.forename: Francis
authors.initials: F
authors.lastname: Verdun
authors.affiliation: Lausanne University Hospital , Department of Radiology, Lausanne, Switzerland.
authors.forename: Sabine
authors.initials: S
authors.lastname: Kobbe-Schmidt
authors.affiliation: Lausanne University Hospital , Institute of Radiation Physics, Lausanne, Switzerland.
authors.forename: François O
authors.initials: FO
authors.lastname: Bochud
keywords: computed tomography; image quality; model observer; observer performance evaluation; three-dimensional analysis technique; volumetric imaging