Are digital images good enough? A comparative study of conventional film-screen vs digital radiographs on printed images of total hip replacement
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The aim of this study was to evaluate the inter- and intra-observer variability and to find differences in diagnostic safety between digital and analog technique in diagnostic zones around hip prostheses. In 80 patients who had had a total hip replacement (THR) for more than 2 years, a conventional image and a digital image were taken. Gruen’s model of seven distinct regions of interest was used for evaluations. Five experienced radiologists observed the seven regions and noted in a protocol the following distances: stem–cement; cement–bone; and stem–bone. All images were printed on hard copies and were read twice. Weighted kappa, κw, analyses were used. The two most frequently loosening regions, stem–cement region 1 and cement–bone region 7, were closely analyzed. In region 1 the five observers had an agreement of 86.75–97.92% between analog and digital images in stem–cement, which is a varied κw 0.29–0.71. For cement–bone region 7 an agreement of 87.21–90.45% was found, which is a varied κw of 0.48–0.58. All the kappa values differ significantly from nil. The result shows that digital technique is as good as analog radiographs for diagnosing possible loosening of hip prostheses.
KeywordsDigital radiographs Analog radiographs Total hip replacement Comparative study
The authors thank P.-E. Isberg, Department of Statistics, Lund University, for help with the statistics.
- 2.Pettersson H (1992) Digital skeletal radiography. In: Resnick D, Pettersson H (eds) Skeletal radiography, NICER series on diagnostic imaging. Merit Communications, London, pp 1–8Google Scholar
- 7.Langen HJ et al. (1993) Comparative evaluation of digital radiography vs conventional radiography of fractured skulls. Invest Radiol 8:686–689Google Scholar
- 8.Swee RG (1997) Screen-film vs computed radiography imaging of the hand: a direct comparison. AJR 168:539–542Google Scholar
- 9.Zähringer M, Krug B, Kamn KF, Wassmer G, Hellmich M, Winnekendonk G, Andermahr J, Gossmann A, Lackner KJ (2001) Detection of porcine bone lesions and fissures: comparing digital selenium, digital luminescence, and analog film-screen radiography. AJR 177:1397–1403Google Scholar
- 13.Piraino DW (1999) Selenium-based digital radiography vs conventional film-screen radiography of the hands and feet: a subjective comparison. AJR 172:177–184Google Scholar
- 15.Gruen TA, McNeice GM, Amstutz HC (1979) “Modes of failure” of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop Relat Res 141:17–27Google Scholar
- 16.Altman D (1991) Practical statistics for medical research. Chapman and Hall, London, p 406Google Scholar
- 17.Chevrot A (1992) Total hip replacement. In: Resnick D, Pettersson H (eds) Skeletal radiography, NICER series on diagnostic imaging. Merit Communications, London, pp 594–614Google Scholar