The impact of selected image-processing schemes on diagnostic performance obtainable from computer-processed CT scans containing simulated nodular lesions was determined from controlled radiological observations. Normal CT scans of the upper abdomen were processed by a computer to simulate the presence of a randomly-located, disk-shaped, low-contrast, nodule within the liver stroma. Results for selected enhancement techniques were tallied using a balanced experimental design. The data indicate that suitably-processed displays significantly improve diagnostic performance expressed in terms of diagnostic errors, information transfer, and the implied noise-relative signal strength, d'. The same mode of display significantly reduces the time required in making diagnostic decisions relative to the status quo.