Diagnosis of extracerebral fluid collections by computed tomography

The computed tomography scans of 90 patients with extracerebral fluid collections were reviewed. Epidural hematomas, acute, subacute, and chronic subdural hematomas, convexity subarachnoid hemorrhages, subdural hygromas, and one epidural empyema were seen. The CT findings were analyzed and correlated with the time elapsed since injury (when known) and the results of radionuclide scans (when available). The overall accuracy of CT in detecting extracerebral fluid was 90% with no acute hemorrhages missed. In subacute and chronic subdural collections, six CT scans were false negative in whole or in part. Three false positive interpretations were made and are discussed.