[Incidental findings on brain MRIPrevalence, clinical management and natural course]

Diagnostic brain imaging has been performed increasingly since the 1990s. A direct result of this is the rise in the detection of incidental findings. The objective of this study is to provide insight into the prevalence, clinical relevance and natural course of incidental findings on brain magnetic resonance imaging (MRI) scans.

Prospective cohort study.

Within the framework of the Rotterdam study, 5800 participants underwent a brain MRI scan during the period 2005-2014. Their average age was 64.9 years, and 55.1% were female. Trained reviewers and experienced neuroradiologists evaluated all scans for clinically relevant incidental findings. We calculated the prevalence of abnormalities discovered, and investigated which clinical management followed in those participants who were referred. On the basis of subsequent scans within the framework of the Rotterdam study we investigated the natural course of findings found in participants who were not referred.

There were incidental findings in 549 of 5800 (9.5%) participants. The most common abnormalities were meningiomas in 143 participants (2.5%) and aneurysms in 134 participants (2.3%). A total of 188 participants (3.2%) were referred to a medical specialist, who chose for a wait-and-see policy or discharge after the initial consultation in 144 participants (76.6%). The majority of meningiomas and aneurysms not referred or untreated, remained stable in size during the average follow-up period of 48-60 months.

Incidental findings on brain MRI are made relatively frequently in people of middle age or older. In 3% of these people these findings are reason for additional clinical evaluation, mostly without further clinical consequences.