Transabdominal ultrasonography in achalasia.

BACKGROUND: The aim of this study was to investigate whether transabdominal ultrasonography can differentiate between achalasia and neoplasms involving the oesophagogastric junction.
METHODS: Ultrasonography was performed in 28 patients with achalasia, 28 sex- and age-matched controls and 13 patients with neoplasms. All studies were done with a 3.5 MHz real time curved array scanner and using an electronic caliper to measure oesophageal wall thickness and the maximum oesophageal diameter. Specificity and sensitivity in making a diagnosis of achalasia and tumours were determined by having unmarked images interpreted by a blinded observer.
RESULTS: Patients with achalasia were identified by recognition of a dilated oesophagus without the presence of a neoplastic lesion (maximum oesophageal diameter (median)=achalasia: 20.0 (14; 25)mm; controls 10.1 (9; 11) mm; P < 0.001). Oesophageal wall thickness was similar in the two groups (achalasia: 3.2 (2.5; 3.4) mm; controls: 2.9 (2.5; 3.4)). In patients with neoplasms, a hypoechoic lesion was identified at the level of the gastric cardia. The sensitivity of making a tumour diagnosis was 100% and the specificity 82%.
CONCLUSION: Transabdominal ultrasonography is a useful, non-invasive diagnostic aid in differentiating patients with primary achalasia from those with neoplastic lesions at the gastric cardia.