Between June 1985 and December 1986, 24 endoscopic intravascular sclerotherapies (5% ethanolamine oleate) were carried out in 17 patients. CT examinations were performed prior to and within 48 hours after all procedures. 1. Esophageal wall thickening was demonstrated by CT scanning within 48 hours after all 24 procedures. Mean diameter of the esophagus before sclerotherapy was 27mm, and after operation, 49mm. Changes of esophageal wall were: 1) 8 cases of the homogeneous wall thicking (33%), 2) 4 localized low density lesions in the wall (17%), and 3) 12 low density lesions of extraesophageal wall in the mediastinum (5%). Chest pain, high fever and esophageal mucosal ulcerlation were seen in patients who had low density lesions of extra-esophageal wall. 2. Pleural effusion occurred after 20 of the 24 procedures (84%). Various pulmonary changes were recognized: Ten cases of atelectasis (42%), 16 dilatations of peripheral pulmonary vessels (66%), and 5 small nodular or irregular shadow (21%). Changes in the mediastinum and pleural space were ascribed to spreading of inflammation from the esophagus, but the changes in the lung field, especially dilatation of peripheral vessels, suggested the penetration of the sclerosant into the lung periphery on the blood stream of pulmonary vessels. 3. CT showed changes of the mediastinum after all 24 procedures (100%), but X-ray examination revealed dilatation of the mediastinum only after 2 procedures (8%). Changes in the pleural space and in the lung field on CT were recognized after 20 procedures (92%), but only after 12 procedures (50%) by X-ray examination. In particular, X-ray examination failed to show shadows on the lung field.(ABSTRACT TRUNCATED AT 250 WORDS)