The barium appearance of intraluminal duodenal diverticulum has been c
lassically described as a ''windsock'' appearance. However, the CT-sca
n appearance of this abnormality has not been well documented. A case
report of a patient with intraluminal duodenal diverticulum is present
ed. The authors believe the CT-scan findings in the patient are virtua
lly pathognomonic for this lesion and propose the term ''halo'' sign b
e applied to this previously undescribed finding. (C) 1998 Elsevier Sc
ience Ltd. All rights reserved.