Bone images from dual-energy subtraction chest radiography in the detection of rib fractures

Eur J Radiol. 2011 Aug;79(2):e28-32. doi: 10.1016/j.ejrad.2010.01.016. Epub 2010 Feb 19.

Abstract

Objective: To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures.

Materials and methods: In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference.

Results: The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p=0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p=0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, p<0.001).

Conclusions: Despite a better image quality, adding ES bone images to standard radiographs of the chest does not provide better sensitivity or improved diagnostic confidence in the detection of rib fractures.

MeSH terms

  • Aged
  • Contrast Media
  • Female
  • Humans
  • Iohexol / analogs & derivatives
  • Male
  • Middle Aged
  • ROC Curve
  • Radiography, Dual-Energy Scanned Projection / methods*
  • Radiography, Thoracic / methods*
  • Retrospective Studies
  • Rib Fractures / diagnostic imaging*
  • Sensitivity and Specificity
  • Statistics, Nonparametric

Substances

  • Contrast Media
  • iobitridol
  • Iohexol