Expect the unexpected

Medicine is beset with traps for the unwary: incidental findings, unintended consequences, perverse incentives, symptoms that are easily missed. This week’s journal has its fair share of examples.

Zoe Morris and colleagues ask how often MRI scans of the brain find things they weren’t looking for (doi:10.1136/bmj.b3016). Their meta-analysis concludes that one in every 37 scans over the past 20 years had an incidental finding. In his linked editorial, Aad van der Lugt warns that rates are probably even higher with modern scanners and imaging protocols (doi:10.1136/bmj.b3107). Patients and research participants should be warned beforehand and carefully counselled afterwards. …