High-resolution endoluminal sonography in achalasia

Area of Science:

• Gastroenterology
• Medical Imaging
• Diagnostic Ultrasound

Background:

• Previous ultrasound studies of the lower esophageal sphincter (LES) in achalasia patients yielded inconsistent results.
• Variability in findings may be attributed to transducer frequency and imaging resolution.

Purpose of the Study:

• To quantitatively compare the muscularis propria of the lower esophageal sphincter (LES) in achalasia patients versus normal volunteers.
• To assess the utility of high-resolution endoluminal sonography in evaluating LES structure in achalasia.

Main Methods:

• Utilized a 20 MHz radial ultrasound transducer housed in a 6.2F catheter.
• Placed the transducer at the LES in 29 achalasia patients and 19 healthy controls.
• Digitized videotaped LES images to measure circular smooth muscle, longitudinal smooth muscle, and total muscularis propria width.

Main Results:

• Significantly greater mean circular smooth muscle width in achalasia patients (0.206 cm) compared to controls (0.124 cm).
• Significantly greater mean longitudinal smooth muscle width in achalasia patients (0.128 cm) versus controls (0.088 cm).
• Total muscularis propria was also significantly thicker in achalasia patients (0.317 cm) than in controls (0.224 cm).

Conclusions:

• High-resolution endoluminal sonography, while not differentiating achalasia from controls, quantitatively confirms thickened LES muscle layers.
• Both mean circular and longitudinal smooth muscle layers are significantly wider in achalasia patients.
• Findings provide objective measurements of LES muscle hypertrophy in achalasia.