[ladyjane]

Originally Posted by ladyjane

Just a little FYI ... as I posted previously, an xray will not always show CT. It often does, but it is not diagnostic for it. I would not want people to think that just because an xray did not show it. It could lead them to make a decision that would not be right for their pup. I would not post it if I had not had personal experience with a CT pup whose xray did NOT show CT.

Here are some links that verify that...

Tracheal Collapse in Dogs: Signs, Causes, and Treatment on MedicineNet

Radiographs may reveal an obviously collapsed trachea, although not always. Fluoroscopy, which allows visualization of the trachea as the dog inhales and exhales, may be necessary to confirm the diagnosis. Fluoroscopy is available only at universities and referral centers.

And...from the American College of Veterinary Surgeons:

ACVS - Tracheal Collapse

Diagnostic tests
Chest x-rays (Figure 2, 3) may help with the diagnosis in some animals, and are useful for ruling out other conditions and looking at the size of the heart. Tracheal collapse is not always visible on regular x-rays, however. Fluoroscopy- a moving x-ray- will allow the veterinarian to check the condition of the dog's trachea when it is breathing in and out (Figure 4). This is important since the size of the trachea can change with the phase of respiration. Endoscopy- viewing the inside of the trachea with a fiberoptic camera - provides the best detail of the inside of the airway (Figure 5) and allows the veterinarian to take fluid samples for culture and microscopic analysis. Veterinarians may also recommend an echocardiogram- an ultrasound of the heart- to evaluate its function, and blood work to check for any other health problems.

Read the highlighted sentences above.