Objective: To identify and review available evidence on the diagnostic yield of brain computed tomographies (CTs) and magnetic resonance images (MRIs) in first-episode psychosis, and examine yield in our own institution (Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec).
Method: Using MEDLINE (1966 to October 2007) and EMBASE (1980 to October 2007), we identified and analyzed studies that examined imaging yields in first-episode psychosis; yield being defined as the percentage of scans showing abnormalities that may result in psychosis. We also retrospectively analyzed diagnostic yields in 46 patients hospitalized in our institution between 2001 and 2006 for first-episode psychosis.
Results: Five studies were deemed relevant. Including our own series, the sample comprised 384 CT and 184 MRI scans. Point estimate for diagnostic yield was 1.3% for CT and 1.1% for MRI scans. These yields likely overestimate clinical usefulness of findings. MRI scans also resulted in a sizeable number of fortuitous, clinically irrelevant findings.
Conclusions: In first-episode psychosis, routine CT or MRI scans are of little benefit and should be reserved for situations where history or examination suggests neurological causation, or possibly for people aged 50 years and older.