Diagnostic errors discovered by CT in patients with suspected stroke.

We assessed the frequency of stroke diagnostic errors revealed by CT in 197 patients. In five patients, CT was an emergency procedure. In the other 192 patients, CT was used to check diagnosis based on routine investigations. All but eight diagnoses (4%) were thereby confirmed. Either hemorrhage was discovered where an ischemic lesion had been suspected (2 cases) or the reverse (3 cases). Disorders other than stroke were found in three patients--subdural hematoma, hydrocephalus, and suspected tumor. Thus, few but important errors were revealed by the CT investigations.