Utilization and utility of diagnostic imaging : Quantitative studies and normative considerations

Today the practice of most medical disciplines is almost unrecognisable without modern radiology. Imaging technology is fascinating, is developing rapidly, and is without doubt beneficial, but there are also concerns about over-utilization, the risks of harm and the costs involved. The overall aim of this dissertation is to improve our understanding of utilization of radiological services, by investigating aspects of the actual use and as perceived by the radiologist. Further, the aim is to illuminate utility issues based on empirical research. The utilization of imaging was investigated through two quantitative surveys. We collected activity data from all radiology institutions in Norway in order to estimate the frequency of radiological examinations. A questionnaire was mailed to Norwegian radiologists to obtain information about their perceptions, actions and reasoning regarding utilization of imaging. We found a significant increase in utilization of diagnostic imaging, especially MRI and CT examinations, leading to a relatively high increase in the collective effective dose. We found that geographical variation in examination frequency was highest for these newer technologies. Accessibility is a likely explanation for both the increase in utilization over time and the geographical variation. According to the radiologists, the major causes of increasing utilization were related to ‘supply and demand’ mechanisms, like expanded technological and medical possibilities, availability of services, and the demands of people and referring clinicians for assurance. They consider over-utilization to comfort patients and clinicians to be the main cause of unnecessary examinations, followed by insufficient referral information. Almost all radiologists reported that they frequently took action in response to inadequate referrals, mainly by contacting the clinician and by checking the medical records. Such actions were primarily motivated by patient safety considerations (risk of complications, radiation dose and low patient age), while somewhat hindered by respect for the judgment of the referrer, the wishes of the patient and practical obstacles. The empirical findings indicate benefits of increasing utilization of imaging in the shape of improved health outcome, reduced pain and lower costs, but also lack of such benefits and possible harm. The overall usefulness of increased utilization can be considered to be limited from a utilitarian perspective. Norms and measures to manage utilization of imaging initiated by the professionals are those that should have the highest potential for increasing the utility of services. Key elements of such measures should be clinical guidelines, giving radiologists more discretionary power, and critical assessment of referrals