Esophagrams

Sometimes megaesophagus is not visible at all on plain radiographs. If the animal has signs of a swallowing disorder, you'll need an esophagram to make the diagnosis. When the megaesophagus is more severe or static, administering some liquid barium and taking a radiograph will be enough to show you the outline of the dilated esophagus. Fluoroscopy is valuable in more subtle cases.

Image 5: An esophageal stricture is the cause of aspiration pneumonia seen on survey radiographs.

Image 6: An esophageal stricture is the cause of aspiration pneumonia seen on survey radiographs.

Even if you have made the diagnosis of megaesophagus on plain radiographs, keep in mind that additional radiographs or fluoroscopy could be indicated. Imaging is useful in monitoring response to treatment for megaesophagus, or for following secondary disease such as aspiration pneumonia. Fluoroscopy can help diagnose additional esophageal problems such as dyssynchrony of the pharyngeal swallowing mechanism or hiatal hernia.

Diagnosing megaesophagus

• Recognize variations of normal (transient).
• Persistent abnormal dilation of the esophagus with gas or fluid.
• If static, plain radiographs may be all you need.
• Use fluoroscopy in cases of less severe or dynamic disease.
• Follow up imaging for response to treatment and monitoring of complications such as aspiration pneumonia.

Dr. Zwingenberger is a veterinary radiologist at the University of California-Davis.