title: Contrast-detail curves for liver CT.
abstract: Contrast-detail curves were constructed for liver computed tomographic (CT) images using an objective method. Stimuli were created by superimposing disks at specified locations on sets of 92 normal liver CT images. Bright and dark disks of 9 sizes and 36 possible image contrasts were used. Sets of 92 stimuli were rendered on film at five window widths (64, 128, 256, 512, and 1024 HU). The contrast-detail (CD) curve flattened substantially for disks larger than 7-mm diameter, and its slope (on a log-log plot) was less than predicted from signal-detection theory. Manipulation of display window manipulation had little impact on this disks' visibility. The results indicate that human observers have difficulty visualizing large, low-contrast details on liver CT scans, and suggest that narrowing the display window will have little effect on this limitation.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts 02115.
authors.forename: P F
authors.initials: PF
authors.lastname: Judy
authors.forename: R G
authors.initials: RG
authors.lastname: Swensson
authors.forename: R D
authors.initials: RD
authors.lastname: Nawfel
authors.forename: K H
authors.initials: KH
authors.lastname: Chan
authors.forename: S E
authors.initials: SE
authors.lastname: Seltzer
mesh_terms: D003287:Contrast Media; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D015588:Observer Variation; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media