MRI-related anxiety levels change within and between repeated scanning sessions.

Magnetic resonance imaging (MRI) scans frequently trigger state anxiety in individuals being scanned. It is not known, however, whether levels of MRI-related anxiety change over the course of a single scan or across repeated scanning experiences. Since changes in state anxiety are known to affect regional brain activity in healthy volunteers, systematic changes in levels of MRI-related anxiety could confound findings from neuroimaging studies. We assessed anxiety levels in eleven healthy male volunteers during a control period and during two MRI scanning sessions. Anxiety levels were highest during the first MRI scan, dropping to control levels or below by the second scan. In addition, anxiety fluctuated within scanning sessions, particularly during the first scan, with levels high at the beginning of the session, decreasing during mid-scan and then increasing again toward the end of the session. These results suggest that habituation in an MRI simulator before participating in a neuroimaging study could help to decrease fluctuations in MRI-related anxiety. Moreover, in studies that address several experimental questions within a single scanning session, experimental designs could be adapted to avoid potential confounds from within-scan variation in scanner-related anxiety.