title: Color coding of radiographic changes over time by means of image addition.
abstract: Differences between sequential radiographs may be displayed in color if the individual radiographs are transformed into monochromatic images and then added. Information in regions where the radiographs are identical is retained whereas differences are emphasized by the color coding that comes about in a quantitative manner from the gray level values in the sequence of radiographs. By using the three additive primary colors, red, blue, and green, two or three radiographs from a sequence may be added. Every possible state of a bone disease, progression, regression, or any combination, will produce a different and specific color code. Different development cycles are described, and the color coding that appears when color image addition is performed is analyzed. The color addition technique should constitute a useful substitute or alternative to subtraction.
authors.affiliation: Department of Oral Radiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Welander
authors.forename: I
authors.initials: I
authors.lastname: Eklund
authors.forename: G
authors.initials: G
authors.lastname: Tronje
authors.forename: W D
authors.initials: WD
authors.lastname: McDavid
authors.forename: S B
authors.initials: SB
authors.lastname: Dove
authors.forename: R
authors.initials: R
authors.lastname: Mähler
authors.forename: C D
authors.initials: CD
authors.lastname: Wilcox
authors.forename: A C
authors.initials: AC
authors.lastname: Mörner
authors.forename: A
authors.initials: A
authors.lastname: Uddhammar
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D003116:Color; D018450:Disease Progression; D006801:Humans; D010485:Periapical Periodontitis / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011861:Radiography, Dental / Q000379:methods*; D013382:Subtraction Technique