• Confidence Intervals and Sample Size Calculations for Studies of Film-reading Performance

      Scally, Andy J.; Brealey, S. (2003)
      The relaxation of restrictions on the type of professions that can report films has resulted in radiographers and other healthcare professionals becoming increasingly involved in image interpretation in areas such as mammography, ultrasound and plain-film radiography. Little attention, however, has been given to sample size determinations concerning film-reading performance characteristics such as sensitivity, specificity and accuracy. Illustrated with hypothetical examples, this paper begins by considering standard errors and confidence intervals for performance characteristics and then discusses methods for determining sample size for studies of film-reading performance. Used appropriately, these approaches should result in studies that produce estimates of film-reading performance with adequate precision and enable investigators to optimize the sample size in their studies for the question they seek to answer.
    • Trauma imaging in and out of conflict: A review of the evidence.

      Beck, Jamie J.W. (2012)
      Aim To review the recent evidence that has resulted from experiences in and out of conflict in relation to improving imaging in cases of major trauma. Method A search of electronic databases, the internet and Cochrane library was undertaken to identify relevant publications which were analysed in terms of quality. Evidence that has emerged from civilian and military practice that could influence the practice of major trauma imaging in future was discussed. Results The importance of speed in assessing patients suffering major trauma is becoming more recognised. There is growing evidence that the use of portable ultrasound at the site of major trauma as first line investigation has potential. In more stable patients, the evidence for whole body CT at the expense of radiography is also growing. The concern regarding availability and radiation dose related to CT scanning remain significant but with the outcome of the recent Major Trauma Review and improvements in CT scanning techniques, such concerns are being addressed. There is limited research in the use of MRI in relation to major trauma. Conclusion Ultrasound at the sight of major trauma has potential but further research will be needed. Factors such as operator training in particular need to be considered. CT scanning remains an important diagnostic tool for patients suffering major trauma and this is borne out by the Major Trauma Review and NICE guidelines. The availability of CT scanning in relation to accident and emergency scanning is a factor the Major Trauma Review has highlighted and the close proximity of new CT scanners to accident and emergency is a factor that will need to be taken into account in strategic planning. Given the growing evidence of CT involvement, the continued practice of cervical spine and pelvic radiography in cases of major trauma should be questioned.