Aim: Magnetic resonance imaging (MRI) is a powerful clinical tool used increasingly in the research setting. We aimed to assess the prevalence of incidental findings in a sequential cohort of healthy volunteers undergoing whole-body MRI as part of a normal control database for imaging research studies.
Materials and methods: 148 healthy volunteers (median age 36 years, range 21-69 years; 63.5% males, 36.5% females) were enrolled into a prospective observational study at a single hospital-based MRI research unit in London, UK. Individuals with a clinical illness, treated or under investigation were excluded from the study.
Results: 43 (29.1%) scans were abnormal with a total of 49 abnormalities detected. Of these, 20 abnormalities in 19 patients (12.8%) were of clinical significance. The prevalence of incidental findings increased significantly with both increasing age and body mass index (BMI). Obese subjects had a fivefold greater risk of having an incidental abnormality on MRI (OR 5.4, CI 2.1-14.0).
Conclusions: This study showed that more than one quarter of healthy volunteers have MR-demonstrable abnormalities. There was an increased risk of such findings in obese patients. This has ethical and financial implications for future imaging research, particularly with respect to informed consent and follow-up of those with abnormalities detected during the course of imaging studies.