The diagnosis of cauda equina syndrome begins with a complete neurologic exam to localize the symptoms and exclude orthopedic causes for limping/lameness. Pain in the lower back also helps to pinpoint the source of the signs and symptoms your pet experiences. Imaging tests such as x-rays, epidurogram, computed tomography, and magnetic resonance imaging (MRI) are useful to confirm the diagnosis.
MRI is a special diagnostic study where your pet is anesthetized and placed into a large and powerful electromagnet. MRI uses the physics of the behavior of atoms in the body when the body is placed in an electromagnetic field. When these electromagnetically excited atoms are subjected to a transmitted radiowave, the atoms resonate, and send back a radiowave signal (echo). The signal is detected and translated by a computer into a 3 dimensional image. These images can be printed on x-ray film directly from the computer or viewed digitally. By varying the frequency of the transmitted radiowave and the time between the transmitted radiowave and the echo, different characteristics of the tissues can be seen. MRI is the gold standard for imaging the nervous system and the most accurate test for diagnosing cauda equina syndrome.
If your veterinarian suspects that a tumor is a potential cause of your pet’s neurologic problem or your dog is senior pet and may have other health problems (heart or lung disease) then your pet should have chest x-rays prior to anesthesia for MRI. Although chest x-rays will help to determine if a cancer is advanced and has spread to the lungs or other organs, it is important to note that microscopic spread of cancer to the lungs will not be detectable with x-rays.