Interobserver agreement and performance score comparison in quality control using a breast phantom: screen-film mammography vs computed radiography.
Our objective was to evaluate interobserver agreement and to compare the performance score in quality control of screen-film mammography and computed radiography (CR) using a breast phantom. Eleven radiologists interpreted a breast phantom image (CIRS model X) by four viewing methods: (a) original screen-film; (b) soft-copy reading of the digitized film image; (c) hard-copy reading of CR using an imaging plate; and (d) soft-copy reading of CR. For the soft-copy reading, a 17-in. CRT monitor (1024x1536x8 bits) was used. The phantom image was evaluated using a scoring system outlined in the instruction manual, and observers judged each object using a three-point rating scale: (a) clearly seen; (b) barely seen; and (c) not seen. For statistical analysis, the kappa statistic was employed. For "mass" depiction, interobserver agreement using CR was significantly lower than when using screen-film ( p<0.05). There was no significant difference in the kappa value for detecting "microcalcification"; however, the performance score of "microcalcification" on CR hard-copy was significantly lower than on the other three viewing methods ( p<0.05). Viewing methods (film or CR, soft-copy or hard-copy) could affect how the phantom image is judged. Paying special attention to viewing conditions is recommended for quality control of CR mammograms.
Department of Radiological Technology, Nagoya University School of Health Sciences, 1-1-20 Daikominami, Higashi-ku, Nagoya, 461-8673, Japan. simamoto@met.nagoya-u.ac.jp
Kazuhiro
K
Shimamoto
Mitsuru
M
Ikeda
Hiroko
H
Satake
Satoko
S
Ishigaki
Akiko
A
Sawaki
Takeo
T
Ishigaki
D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods* / Q000592:standards; D015588:Observer Variation; D019047:Phantoms, Imaging; D011786:Quality Control; D014057:Tomography, X-Ray Computed; D014963:X-Ray Intensifying Screens