2016 ACVIM Forum Research Abstract Program

This was a double blinded controlled study of dogs with an acute onset T3-L3 compressive myelopathy secondary to Hansen Type I intervertebral disk disease. All patients had standard preanesthetic screening and underwent magnetic resonance imaging of the T3-L3 spine using a Siemens 1.5T scanner. Images were obtained, in at least, the following sequences: standard T2-W sagittal and transverse, STIR dorsal, and SPACE. All dogs underwent a decompressive hemilaminectomy based on the imaging findings. The MRI sequences were randomized and three blinded individuals interpreted the MR images a total of three times. The evaluators were of different skill levels, including one ECVN diplomate, one ACVR diplomate, and a third year neurology resident. The standard T2-weighted and SPACE sequences were individually evaluated for site, side, and degree of compression as well as surgical recommendation and subjective confidence of imaging findings. 23 dogs met the inclusion criteria. There was statistically significant agreement for both site and side (P-Value <0.001) between the standard T2-weighted spin echo imaging and SPACE. There was complete agreement by all three researchers concerning both the site and side of disk herniation (comparing standard T2weighted standard spin echo imaging and SPACE) for 20 of the 23 dogs, and partial agreement for the other 3 dogs. Compressive Length Ratio (CLR) estimates by the two methods were similar, with more variability due to evaluator variability than to differences between the two systems, and similar internal (intra-rater) variabilities between the two systems. The degree of compression, as measured by the standard mild/medium/severe rating protocol shows significantly positive association between the two methods, although not as strong as that between the two methods for the CLR measurements.