Optimal kVp selection for dual-energy imaging of the chest: Evaluation by task-specific observer preference tests

D. B. Williams, J. H. Siewerdsen, D. J. Tward, N. S. Paul, A. C. Dhanantwari, N. A. Shkumat, S. Richard, J. Yorkston, R. Van Metter

Research output: Contribution to journalArticlepeer-review

Abstract

Human observer performance tests were conducted to identify optimal imaging techniques in dual-energy (DE) imaging of the chest with respect to a variety of visualization tasks for soft and bony tissue. Specifically, the effect of kVp selection in low- and high-energy projection pairs was investigated. DE images of an anthropomorphic chest phantom formed the basis for observer studies, decomposed from low-energy and high-energy projections in the range 60-90 kVp and 120-150 kVp, respectively, with total dose for the DE image equivalent to that of a single chest radiograph. Five expert radiologists participated in observer preference tests to evaluate differences in image quality among the DE images. For visualization of soft-tissue structures in the lung, the [60130] kVp pair provided optimal image quality, whereas [60140] kVp proved optimal for delineation of the descending aorta in the retrocardiac region. Such soft-tissue detectability tasks exhibited a strong dependence on the low-kVp selection (with 60 kVp providing maximum soft-tissue conspicuity) and a weaker dependence on the high-kVp selection (typically highest at 130-140 kVp). Qualitative examination of DE bone-only images suggests optimal bony visualization at a similar technique, viz., [60140] kVp. Observer preference was largely consistent with quantitative analysis of contrast, noise, and contrast-to-noise ratio, with subtle differences likely related to the imaging task and spatial-frequency characteristics of the noise. Observer preference tests offered practical, semiquantitative identification of optimal, task-specific imaging techniques and will provide useful guidance toward clinical implementation of high-performance DE imaging systems.

Original languageEnglish (US)
Pages (from-to)3916-3925
Number of pages10
JournalMedical physics
Volume34
Issue number10
DOIs
StatePublished - 2007

Keywords

  • Chest imaging
  • Dual-energy imaging
  • Flat-panel detector
  • Imaging performance
  • Imaging task
  • Lung cancer
  • Observer study
  • Preference tests
  • Technique optimization

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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