Sonographic findings in achalasia.

PURPOSE: The aim of this study was to describe the sonographic features of achalasia.

METHODS: Thirty-five patients with achalasia (17 men and 18 women; mean age, 43 years) were examined with transabdominal sonography, and the findings were compared with those in 41 volunteers without esophageal disease (21 men and 20 women; mean age, 41 years), 10 patients with gastroesophageal junction carcinoma (7 men and 3 women; mean age, 55 years), and 4 patients with peptic stricture (3 men and 1 woman; mean age, 39 years). The distal end of the esophagus was evaluated, and the thickness of the esophageal wall was measured.

RESULTS: In 28 fasting patients (80%) with achalasia, sonography showed dilatation, retention of fluid, and smooth narrowing of the distal esophagus (like a bird's beak). These findings were not identified in the other patients or volunteers. In addition, in 6 of 7 achalasia patients who had no sign of esophageal dilatation in the fasting state, water retention was demonstrated after ingestion of water, bringing the total number of patients with achalasia with positive sonographic findings to 34 (97%). In patients with achalasia, the mean thickness (+/- standard deviation) of the esophageal wall at the gastroesophageal junction was 4.8 +/- 0.9 mm (range, 3.6-7.2 mm). The thickening was regular, symmetric, and localized to the gastroesophageal junction. In the volunteers, the mean thickness of the esophageal wall was 2.3 +/- 0.5 mm (range, 1.4-3.5 mm). The difference between the 2 groups was statistically significant (p < 0.001). In the patients with carcinoma, the mean wall thickness was 17.0 /+ 1.1 mm, and the thickening was irregular. In the patients with peptic stricture, the mean wall thickness was 5.1 +/- 1.1 mm (range, 3.8-8.3 mm), and the thickening was irregular and occupied a longer segment of the distal esophagus.

CONCLUSIONS: In patients with achalasia, transabdominal sonography clearly shows the regular thickening of the esophageal wall, water retention, dilatation of the distal esophagus, and the bird's beak appearance. Sonography may help in differentiating achalasia from carcinoma and peptic stricture of the gastroesophageal junction, which is difficult to do with other modalities.