title: Two K versus 4 K storage phosphor chest radiography: detection performance and image quality.
abstract: The purpose of this study was to evaluate the effect of matrix size (4-K versus 2-K) in digital storage phosphor chest radiographs on image quality and on the detection of CT-proven thoracic abnormalities. In 85 patients who underwent a CT of the thorax, we obtained two additional posteroanterior storage phosphor chest radiographs, one with a matrix size of 3,520x4,280 (=4-K) and the other with a matrix size of 1,760x2,140 (=2-K). Acquisition, processing and presentation parameters were identical for all radiographs. Two radiologists evaluated the presence of mediastinal, pleural, and pulmonary abnormalities on hard copies of the radiographs, applying ROC analysis. In addition, four radiologists were asked to subjectively rank differences in image quality and to assess the demarcation of anatomic landmarks comparing the images in a blinded side-by-side manner. These data were analyzed using a two-sided binomial test with a significance level of P<0.05. Both tests, the ROC analysis of the detection performance and the binomial test of the subjective quality ratings, did not reveal significant differences between the two matrix sizes. Compared to 2-K radiographs, 4-K storage phosphor chest radiographs do not provide superior detection performance or image quality when evaluated in identical hard copy formats.
authors.affiliation: Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria. claus.koelblinger@meduniwien.ac.at
authors.forename: Claus
authors.initials: C
authors.lastname: Koelblinger
authors.forename: Mathias
authors.initials: M
authors.lastname: Prokop
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Johannes
authors.initials: J
authors.lastname: Sailer
authors.forename: Fabiola
authors.initials: F
authors.lastname: Cartes-Zumelzu
authors.forename: Cornelia
authors.initials: C
authors.lastname: Schaefer-Prokop
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008171:Lung Diseases / Q000000981:diagnostic imaging; D008297:Male; D008477:Mediastinal Diseases / Q000000981:diagnostic imaging; D008875:Middle Aged; D015233:Models, Statistical; D015588:Observer Variation; D010995:Pleural Diseases / Q000000981:diagnostic imaging; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data