Home / X-Ray, Fluoroscopy, And Bronchoscopy: What Each Test Shows

X-Ray, Fluoroscopy, And Bronchoscopy: What Each Test Shows

If your vet suspects tracheal collapse, you may hear three test names in a row: X-ray, fluoroscopy, and bronchoscopy. They are not repeats of each other. Each one answers a different question, and each has a limit. Here is what veterinary schools and the American College of Veterinary Surgeons say about them, in plain words.

The Exam Comes First

Cornell University College of Veterinary Medicine says your vet will do a physical exam and will likely suggest blood work to check your dog's overall health. It adds that a cough can often be set off by gently pressing the throat, but that confirming the diagnosis may need one or more further tests. The American College of Veterinary Surgeons also lists blood work as part of the general workup.

Chest X-Rays: A Snapshot

The American College of Veterinary Surgeons says chest X-rays may help with the diagnosis in some pets, and are useful for ruling out other conditions and looking at the size of the heart. It also says tracheal collapse is not always visible on regular X-rays. University of Missouri Veterinary Health Center explains why: the trachea is not flattened at all times, and an X-ray only captures a moment in time. Cornell says the same thing, noting that the trachea can collapse during breathing in or breathing out.

The numbers show it. In a 2024 Seoul National University study of 110 small dogs, every dog was diagnosed by fluoroscopy, and X-rays confirmed the collapse in 71 of the 110 dogs, about 64.5 percent. Embrace Pet Insurance writes that X-rays taken at rest can miss up to 40 percent of tracheal collapses. So a normal X-ray does not settle the question.

Fluoroscopy: The Airway In Motion

Fluoroscopy is a moving X-ray. The ACVS says it lets the team check the trachea as the dog breathes in and out, which matters because the size of the trachea changes with each breath. Mizzou says it gives real-time images and can also show what happens during a cough, to work out where the collapse is. Cornell says it can show where the collapse is occurring and how severe it is. Mizzou notes that fluoroscopy is used at many universities and specialty hospitals. Ask your vet where it is done.

Bronchoscopy: A Look From The Inside

For this test a thin camera is passed through the mouth into the trachea and bronchi. Cornell says it requires general anesthesia and lets the clinician see the airway directly while the dog breathes. The ACVS says the scope gives the most detail of the inside of the airway and allows fluid samples to be taken for culture and analysis. Mizzou adds that it shows inflammation or irritation linked to infection or chronic coughing, and allows samples for bacterial culture and microscopic evaluation.

Heart And Other Tests

The ACVS lists an echocardiogram, an ultrasound of the heart, to evaluate heart function. Mizzou says that if lung disease is a worry, a CT scan may be suggested, because it gives a much better picture of the lungs and airways than standard X-rays. VCA Animal Hospitals says other causes of coughing, including congestive heart failure, must be ruled out, and that sometimes heart disease and collapsed trachea are present at the same time. See Heart Disease And Tracheal Collapse.

Side By Side

Where The Grade Comes From

The ACVS describes tracheal collapse as graded from mild, Grade 1 with 25 percent collapse, to severe, Grade 4 with 100 percent collapse. In the Seoul study the grade was assigned from fluoroscopy, from the largest drop in tube width at each of four spots: the neck, the thoracic inlet where the trachea enters the chest, inside the chest, and the carina where the airway splits. Embrace writes that grading is typically done by bronchoscopy or fluoroscopy. That study also found that the grade and location seen on fluoroscopy did not line up with how bad the cough was, so the grade is only part of the picture. See Grades 1 To 4.

Questions To Ask Before Testing

• Which test do you want, and what question will it answer?
• Will my dog need anesthesia, and what are the risks for my dog's age and heart?
• If the X-ray is normal, does that rule out collapse?
• Where is fluoroscopy done, and can records be sent?
• What will the written estimate cover? Embrace lists a diagnostic workup with X-rays and fluoroscopy at $500 to $1,500.

Bring a phone video of the cough. Embrace notes that the cough often stops the moment a dog reaches the clinic. More questions are at Questions To Ask Your Vet.

To see listed practices near you that say they treat tracheal collapse, use Find A Practice. We show every listed practice that serves your area, and you choose who, if anyone, to contact.