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9 ‘Incidentalomas’ in diagnostic imaging: the role of the radiologist in over-investigation and over-diagnosis
  1. Richard Mendelson


Incidentalomas (incidental lesions [ILs] discovered on diagnostic imaging [DI], unrelated to the patient’s clinical presentation) are increasingly common. For example, about 5% of abdominal CT scans lead to ILs; thyroid nodules are found in up to 70% of neck ultrasound exams performed for non-thyroid problems; incidental lung nodules are common. This prevalence is due to: (a) the increasing number of patients undergoing DI; (b) the high resolution of modern equipment; (c) the largely untargeted nature of cross-sectional imaging. With regard to (a), up to about a third of DI requests are inappropriate. The drivers for inappropriate imaging arise from: referrers (a knowledge gap, defensive medicine, time constraints on patient consultations and an abandonment of the clinical paradigm in favour of imaging); from radiologists (reluctance or failure of radiologists to act as gatekeepers; marketing by radiology practices); and from patients’ expectations engendered by the media and internet.

Some ILs are of fortuitous benefit to the patient (e.g aortic aneurysms), but others are of debatable benefit and still others –the majority – are of little or no significance. However the latter often lead to anxiety, and the cost and risk of further investigation. The resulting problem of over-investigation and over-diagnosis is increasingly recognised – so-called ‘cascade syndrome’.

The causes of this phenomenon overlap with the drivers of inappropriate imaging (above): defensive medicine and the perceived need for certainty, the abandonment of the clinical diagnostic paradigm, a knowledge gap on the part of imaging specialists and/or referrers regarding the significance or otherwise of some ILs, and economic gain in a competitive radiological marketplace. Confounding the issue is the relative lack of consensus and consistency among radiologists in reporting and managing ILs.

Improvement in the management of incidentalomas is contingent on several factors. Radiologists need to fulfill their roles as gatekeepers and consultants thus reducing inappropriate imaging and achieving appropriate management by (a) effective and meaningful consultation between radiologist and referring doctor; (b) a more narrative, nuanced and/or discretionary approach to reporting - taking account of the patient’s age and co-morbidities as well as the natural history of the IL, while being mindful of potential ethical issues of such an approach; (c) the involvement of patients in decision-making in regard to their imaging findings.. There is a need for greater availability of multidisciplinary evidence-based guidelines for the commoner ILs and for increased research into their natural history.

This workshop will expand on the above issues with the following structure:

1. Introduction - Richard Mendelson

  • Incidental lesions (ILs) – the extent of the problem?

  • Categories – beneficial, don’t know, insignificant

  • Examples of each of above

  • Reasons for increase in prevalence

  • Outline of drivers of (a) increased imaging/inappropriate imaging, and (b) follow–up (over)investigation of ILs

  • Possible solutions

2. Some common examples of ILs - Assoc Prof Tom Sutherland MBBS MMed Grad Dip Clin Ed. FRANZCR Radiologist, St Vincent’s Hospital, Victoria, Australia

  • Thyroid nodules

  • Some abdominal ILs

  • Lung nodules

3. ‘Over-diagnosis from the radiology perspective’ - Dr Lorna Gibson MBChB, FRCR Radiologist, University of Edinburgh

4. What does the GP expect/want from the radiologist in relation to incidental findings - Dr Iona Heath CBE FRCGP General Practitioner and Past President of Royal College of GPs (UK)

5. Discussion

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