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.
Shimamoto
Kazuhiro
K
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
Ikeda
Mitsuru
M
Satake
Hiroko
H
Ishigaki
Satoko
S
Sawaki
Akiko
A
Ishigaki
Takeo
T
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