Receiver operating characteristic analysis of fracture and pneumonia detection: comparison of laser-digitized workstation images and conventional analog radiographs

Radiology. 1993 Jan;186(1):263-8. doi: 10.1148/radiology.186.1.8416576.


Forty pneumonia and 40 fracture cases were matched by patient age and gender with normal cases. Pediatric cases constituted 25% of this sample. All 160 examinations were laser-digitized at a spot size of 210 microns, a contrast resolution of 12 bits, and a spatial resolution of 2.35 line pairs per millimeter. The digitized images were transmitted 5 miles over a dedicated telephone line at a T1 rate from Francis Scott Key Hospital to Johns Hopkins Hospital (both in Baltimore, Md). At Johns Hopkins Hospital, eight radiologists interpreted the original analog radiograph and corresponding soft-copy display (1,280 x 1,024 pixels). Findings, confidence ratings, and image quality were reported for each reading. A receiver operating characteristic (ROC) analysis was conducted to compare observer performance under the analog and digital reading conditions. The overall sensitivity of the analog method was 89% versus 78% for the digital method (P < .001), while the specificity values were 96% and 92%, respectively (P > .20). ROC analysis similarly indicated a statistically significant difference in favor of analog radiographs (P = .028).

Publication types

  • Comparative Study

MeSH terms

  • Child
  • Female
  • Fractures, Bone / diagnostic imaging*
  • Humans
  • Lasers
  • Male
  • Middle Aged
  • Pneumonia / diagnostic imaging*
  • ROC Curve
  • Radiographic Image Enhancement*
  • Radiology Information Systems*
  • Sensitivity and Specificity