Evaluation of Diagnostic Imaging Methods to Diagnose and Prognose the Cauda Equina Compression Syndrome
The clinical appearance of hind limb lameness with neurologic deficit is a very common diagnosis especially in large breed dogs. The aim of this study was to find the best diagnostic imaging workup of the Cauda equina compression syndrome (CECS) in dogs and the order of the different methods--radiology, myelography, computed tomography (CT) and Magnetic resonance tomography (MRT).
Materials & Methods
Plain radiographs in two planes of the lumbosacral junction were always the first step. Additionally a stress radiograph in flexed position was done to determine any displacement of the sacrum. If there was the suspicion of an additional lesion further cranial, a myelogram was performed. CT's were done with 2 mm slice thickness and 2mm slice interval in dorsal recumbency--in extended and flexed position. One of these positions also after i.v. contrast application. 3D reconstructions and reconstructions in further planes, such as sagittal, coronal and oblique views were done. MRT was done in T1, T2 weighted sequences and in all different planes, native and after i.v. contrast application.
The plain radiograph in two planes gives you a good overview of the skeletal situation and is an essential tool to plan further steps. The stress (flexed) view gives information if there is any dynamic component. If there are any degenerative signs such as spondylosis, spondylarthrosis, CT should be performed. The different appearance of the vertebral canal and neuroforamina with flexed and extended limbs gives further information. Also the enhancement of the i.v. contrast study shows inflammation and venous congestion. If no diagnosis can be made through radiographs or only disc space narrowing, opacification of the neuroforamina and/or displacement of the sacrum can be seen on radiographs MRT is the most sensitive method. With MRT a good evaluation of the nerve roots of the Cauda equina and the surrounding fat is possible. Additional to these degenerative myolopathies, edema and bleeding can bee evaluated.
The diagnostic workup step by step helps to find the real location of pain and neural compression fast and with minimal effort. All this information is very helpful for the further planning of the neurologist.