Gwyneth C. Weatherburn

A comparison of conventional film, CR hard copy and PACS soft copy images of the chest: analyses of ROC curves and inter-observer agreement

STUDY OBJECTIVE The aim of this study was to determine whether the accuracy of diagnosis of a spectrum of chest pathology was affected by the imaging technique used, and to compare conventional film/screen, hard copy computed (phosphor plate) radiography (CR) and soft copy CR (PACS) images. MATERIALS AND METHODS For each of 44 patients who had a CT examination of the thorax, PA and lateral chest radiographs were produced using conventional film, hard copy CR and soft copy PACS images. Five radiologists independently scored all images for the presence of abnormalities. The data were analysed in two stages using the result of the CT scan as the reference standard diagnosis: firstly, to investigate differences in abnormality scores between image modalities and observers using ROC analysis; secondly, to investigate the agreement of the diagnoses with the reference standard by the analysis of kappa scores. RESULTS The ROC analyses and comparison of kappa scores showed no differences between image modalities (P=0.72, P=0.87), but highly significant differences between observers (P<0.001, P=0.003). CONCLUSION The detection of chest lesions did not vary between conventional film, CR hard copy and PACS soft copy images. For all three image types, there were statistically significant differences between observers.

Evaluation of a hospital-wide PACS: costs and benefits of the Hammersmith PACS installation

The unusual nature of sites chosen for hospital-wide PACS implementations and the very small number of proposed implementations make evaluation a complex task. The UK Department of Health is funding both the evaluation and implementation of a hospital-wide PACS. The Brunel University evaluation of the Hammersmith Hospital PACS has two main components: an economic evaluation of the costs and benefits of hospital-wide PACS installations and an exercise in monitoring the implementation process. This paper concentrates on the economic component.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Evaluation of PACS at Hammersmith Hospital: assessment of radiology department performance in the intensive care unit

The hospital-wide PACS installation at Hammersmith Hospital is the subject of an independent technology evaluation exercise. This paper focuses on one aspect of the evaluation: the assessment of the impact of PACS on the performance of the radiology department in the intensive care unit (ICU). A quasi-experimental before and after research design has been adopted and initial baseline measurements have been undertaken of the time intervals between the various events from the radiograph request to the initiation of a subsequent clinical action. The results presented suggest that the radiology department at Hammersmith is currently performing well with an interval of about 10 minutes from the radiograph being taken to it being available for viewing in the ICU for non-routine radiographs (taken after 11.00 and before 9.00). The main findings from this study to date relate to the appropriateness of the research methods used, given the disappointing response rates for specific variables, and thus the potential for bias in the results obtained.

Technology assessment of PACS: measurement and analysis of radiologists' reporting times when reporting from film

This paper describes a research project which explored the reasons for variation in reporting time by senior radiologists. The objective was to identify factors which are important to control for in an assessment of the impact of the introduction of a PACS on reporting times. An observational study of reporting by senior radiologists at Hammersmith Hospital was initially undertaken for a period of 25 days. At all times during the working day on the days chosen for the study, an independent health service researcher observed the radiologist reporting on both urgent and non-urgent images. Data were collected on a variety of factors including the time taken to produce the report, the number and nature of the images viewed and the disturbances that occurred. Regression analysis techniques were used to analyze the data in order to identify the factors which explain variation in reporting times. The paper reports the research methods and results from the baseline data on working with conventional hard copy film at Hammersmith Hospital.

Costs and benefits of hospital-wide PACS networks: an overview of a comprehensive evaluation exercise

The experimental site for the evaluation reported was the Hammersmith Hospital, London. The study adopted an economic perspective in that the focus was on the change in various elements of cost and the change in various parameters of benefit following the implementation of a hospital-wide PACS. Comparison was made of hospital operation in a film-based situation with operation in a PACS-based situation. Some of the research activities focused on the radiology service itself at Hammersmith, others focused on other areas of the hospital where radiological information was seen as an important component in clinical decision-making, and others looked outside the hospital. In terms of operational, clinical and patient benefits, the evaluation found no significant indicators of disadvantages of PACS and many examples of significant actual measurable benefits or perceived advantages by users. However, as one might expect, these advantages come at a significant net cost.

Evaluation of PACS at Hammersmith Hospital: assessment of radiology performance in the accident and emergency department

In the Accident and Emergency Department (A&E) x-ray images are used to assist in the initial diagnosis and management of the patient. It is therefore expected that the main benefits of PACS in A&E will arise from the ability of clinicians to manipulate the digital image and thus potentially improve their diagnostic performance. In order to evaluate whether this benefit is realized or not a case-study evaluation has been undertaken; this has three components: (a) monitoring the extent of misdiagnosis by A&E clinicians before and after the PACS implementation; (b) an examination of the decision performance of the clinician-image combination for the visualization of the lower cervical spine/upper thoracic spine and of fracture of the head of the radius; and (c) a more general monitoring of the impact of the image archiving and communication aspects of PACS. In this paper the study of the impact of PACS on misdiagnosis by A&E clinicians at the Hammersmith Hospital, London, is described and pre-PACS results for the period 31 March 1992 to 30 September 1992 are presented.

How can the impact of PACS on inpatient length of hospital stay be established

Many have argued that the introduction of a large-scale PACS system into a hospital will bring about reductions in the length of inpatient hospital stays. There is currently no convicting empirical evidence to support such claims. As part of the independent evaluation exercise being undertaken alongside the Hammersmith Hospital PACS implementation, an assessment is being made of the impact of PACS on length of stay for selected patient groups. This paper reports the general research methods being employed to undertake this assessment and provides some baseline results from the analysis of total hip replacement patients and total knee replacement patients treated prior to the introduction of PACS.