Assessment of Intraaxial and Extraaxial Brain Lesions with Digitized Computed Tomographic Images versus Film: ROC Analysis

Rationale and Objectives. The authors evaluated the diagnostic accuracy of viewing computed tomographic (CT) scans as film versus soft-copy images at a workstation. Methods. Receiver operating characteristic analysis of the interpretation of 202 CT scans (103 were normal, 99 were abnormal) by five neuroradiologists was performed. Abnormal images contained high- or low-attenuation intraaxial lesions or extraaxial fluid (subdural, subarachnoid, or epidural hemorrhage) Hard copies were read on a standard light box, and digital images were examined at a 1,024× 1,250 workstation. Lesion location and type and confidence ratings were recorded on a worksheet. Results. There were no statistically significant differences in diagnostic accuracy between the two display modes. Reader performance was slightly better with the workstation in the assessment of low-attenuation lesions. Conclusion. Diagnostic accuracy is similar for CT scans displayed at a workstation and those displayed as hard copy in the assessment of subtle intra- and extraaxial brain lesions.