Incidental neuroimaging findings: lessons from brain research in volunteers.

Over the last few years, brain research in volunteers that are considered healthy has increasingly used neuroimaging methods. The actual imaging techniques are tailored to the scientific issue under investigation but such imaging sessions often include high-resolution structural brain imaging. Accordingly, these brain scans are not ideal but nonetheless sensitive for detecting the presence of brain pathologies. Analyses of large cohorts of brain scans obtained for nondiagnostic reasons in volunteers who were deemed healthy have revealed incidental findings in up to almost every fifth individual [1]. Only a minority of these findings, however, are clinically significant and only about 1% showed findings that required rapid medical attention. These levels of prevalence are largely in accordance with those reported for disease-unrelated observations in clinical populations and for populations screened for fitness such as air pilots [2,3]. Not surprisingly, there is an age-related increase in incidentally detected findings but asymptomatic anomalies may be found as early as in paediatric populations [4,5].