The significance of an air oesophagogram visualised on conventional chest radiographs

Air may occasionally be seen outlining the entire oesophagus on conventional chest radiographs, this being referred to as an air oesophagogram. The reported causes of this radiological sign are reviewed. The chest radiographs of 24 cases of scleroderma with oesophageal involvement, and 29 cases of achalasia, have been studied. An air oesophagogram was seen in three cases (12.5%) of scleroderma and three cases (10%) of achalasia, without an oesophageal air fluid level and with air in the gastric fundus. An air oesophagogram has not been previously described in achalasia. The significance of this sign, which was found to occur in advanced scleroderma and in early achalasia, is discussed.