Background: Brain imaging studies using magnetic resonance imaging (MRI) sometimes reveal incidental findings (IFs) that might be relevant to some of the health issues in research participants. Although professional communities have discussed how to manage these IFs, there is no global consensus on the concrete handling procedures including how to inform participants of IFs.
Methods: First, this study reviewed previous studies for the number of IFs discovered in brain imaging studies using MEDLINE. Second, a multi-institutional study determined the number of IF discoveries and evaluated the method of informing participants at multiple institutions, which participated in a national brain science project in Japan.
Results: Both the review and multi-institutional study showed that IFs with a high urgency level were discovered in 0-2.0% of participants, including healthy volunteers, and that the rate of IF discovery in general was higher in studies conducted in elderly population. Moreover, multi-institutional study suggested the criteria used to judge whether or not to inform participants of IFs may differ by institution.
Conclusions: Our results suggest that in order to ensure informing the participants of high urgency IFs, physicians who are capable of interpreting brain images clinically should review all brain images, and the establishment of a support system is required for brain imaging studies at nonmedical institutions. Since the method of informing participants of IFs might affect their understanding and acceptance of IFs, which are related to managing risks of false "clean bill of health" or psychological impacts of informing IFs, further research focusing on communication of IFs is needed.
Keywords: incidental findings; magnetic resonance imaging study; quantitative study; research ethics; review.