Reading radiographs in chronological order, in pairs or as single films has important implications for the discriminative power of rheumatoid arthritis clinical trials

Rheumatology (Oxford). 1999 Dec;38(12):1213-20. doi: 10.1093/rheumatology/38.12.1213.


Objective: To determine the influence of reading series of films in chronological order, in pairs with unknown time sequence, or as single films, on precision and sensitivity to change.

Methods: Two studies were performed with 10 and 12 patients fulfilling the American College of Rheumatology criteria. In Study 1, two sets of films with a 1 yr interval were scored in chronological order, in pairs, and as single films. In Study 2, four sets of films, with a 1 yr interval each, were scored in chronological order, as single films and as single-pair (right and left together). All films were scored with the Sharp/van der Heijde method by two independent observers. Data were analysed with a repeated measures ANOVA using a full mixed effects model. Two generalizability (G) coefficients were constructed for reliability and for change.

Results: Study 1: the interobserver reliability was similar for the three methods (G(reliability) chronological 0.94, paired 0.88, single 0.93); progression was a mean increase (averaged over patients, observers and methods) from 26 to 37 (P=0.046). The sensitivity for change was greater for the chronological than for the paired and single scoring (G(change) 0.39, 0.22 and 0.24, respectively). Study 2: the interobserver reliability was 0.86 for chronological, 0.76 for single-pair and 0.91 for single readings. Significantly more progression was measured with the chronological compared with the single-paired and single methods (15.9 vs 8.5 and 8.3; P=0.0001). A constant progression was suggested by chronological reading, in contrast to a stabilization in the other two methods after 1 yr.

Conclusion: Reading films in chronological order is most sensitive to change in a time period up to 3 yr follow-up; this was already present after 1 yr, but even more pronounced with longer follow-up.

MeSH terms

  • Analysis of Variance
  • Arthritis, Rheumatoid / diagnostic imaging*
  • Chronology as Topic
  • Follow-Up Studies
  • Humans
  • Models, Statistical
  • Observer Variation
  • Outcome Assessment, Health Care
  • Radiography
  • Randomized Controlled Trials as Topic*
  • Research Design
  • Sensitivity and Specificity