Recognition of abnormalities on computed scout images in CT examinations of the head and spine.

We investigated the information which can be obtained from the computer-generated digital radiographs ("scout images") performed for CT examinations. One hundred CT examinations of the head and one hundred of the spine were randomly selected and retrospectively reviewed: the head scout images were acquired in the lateral projection, and those of the spine in the lateral and/or anteroposterior projections. In 122 patients with demonstrable pathology on the CT sections or the scout image, a total of 154 abnormalities was found, of which 31 (20%) were identified only on the scout images. Eight (25.8% of this number) required additional clinico-radiologic study and were therefore designated as clinically pertinent positives. This study demonstrates that the CT scout image may contain considerable, clinically relevant information which is not available on, or is complementary to, the CT sections.