Detailed ultrasonographic mapping of the pelvis in clinically normal horses and ponies

Objective-To map the equine pelvis using ultrasonography, validated by use of computed tomography (CT), magnetic resonance imaging (MRI), and measurem ents of frozen cadaver slices. Animals-6 ponies and 6 horses. Procedure-Ultrasonographic examination of the pelvis was performed on 6 cli nically normal ponies. Measurements were obtained for imaged structures. Co mputed tomography, MRI, and measurements of frozen sections were performed after death and used to verify measurements. Linear regression determined t he degree of correlation between measurements obtained ultrasonographically and the other modalities. Six clinically normal horses were then examined by use of ultrasonography. For each structure measured mean, SD, and range were calculated. Results-Data obtained from ponies revealed high correlations between ultras onographic findings and those of CT MRI, and frozen section measurements (r (2) = 0.97, r(2) = 0.99, and r(2) = 0.99, respectively). Differences betwee n structures measured on each side of the pelvis were not significant. Vari ation in size of structures was not associated with weight of horses. A cor relation was not found between weight of horses and ponies and size of stru cture. Conclusions and Clinical Relevance-Ultrasonography can be used to accuratel y measure and evaluate the musculoskeletal structures of the pelvis of hors es. The use of CT MRI, and measurements of frozen sections provided a means of validating the ultrasonographic measurements. Reference range values de termined in our study can be used to evaluate horses with suspected pelvic disease.