Mediastinal lymphoma in dogs is homogeneous compared to thymic epithelial neoplasia and is more likely to envelop the cranial vena cava in CT images.

In order to identify CT signs that could be used to distinguish cranial mediastinal lymphoma and thymic epithelial neoplasia, a retrospective case-control study was done. Associations between CT signs and diagnosis were tested using binary logistic regression and results expressed as odds ratio and 95% confidence interval. Sixty-two dogs that had thoracic CT and confirmed diagnosis of lymphoma (n = 33) or thymic neoplasia (n = 29) were sampled. Thymic neoplasms included 24 thymomas and five thymic carcinomas. Dogs with thymic epithelial neoplasia were significantly older than dogs with lymphoma (median age 8.6 years versus 6.0 years, P = .007), but there were no significant differences in prevalence of clinical signs. Diagnosis of thymic epithelial neoplasia was associated with heterogeneous attenuation in pre- (odds ratio 23.3, 95% confidence interval, 4.5-121.1) and post-contrast (odds ratio 30.7, 95% confidence interval, 3.6-265.0) images. Conversely, envelopment of the cranial vena cava by the mass was less likely with thymic epithelial neoplasia than lymphoma (odds ratio 0.07, 95% confidence interval, 0.007-0.66). Greater standard deviation of Hounsfield unit values in post-contrast images was associated with thymic epithelial neoplasia (P = .005). Based on ROC analysis, SD > 17HU of the mass in post-contrast images had a sensitivity of 72% and specificity of 79% for thymic epithelial neoplasia. There were no significant differences in morphology, prevalence of calcification, mediastinal lymphadenopathy, cranial vena cava invasion, collateral vessels, or pleural fluid associated with these tumors. Thymic epithelial neoplasms tended to occur in older dogs and were heterogeneous in CT images, whereas mediastinal lymphoma was more homogeneous and more likely to envelop the cranial vena cava.

Canine Elbow Realignment Osteotomy (CERO): Validation of the Accuracy of Acute Radial Lengthening in a Cadaveric Incongruency Model.

OBJECTIVE: To verify the ability of a novel Canine Elbow Realignment Osteotomy (CERO) system for acute axial radial or ulnar lengthening to restore normal elbow congruency in a shortened radius cadaver model using assessment by computed tomography (CT). STUDY DESIGN: In vitro cadaver study. ANIMALS: Five pairs of greyhound forelimbs from animals euthanatized for reasons unrelated to the study. METHODS: CT of each elbow was performed (1) pre-operatively (pre-op), (2) after placement of a linear motor IMEX™ external skeletal fixator (ESF) on the radius with diaphyseal ostectomy and radial shorting of 1-5 mm (post-ESF), and (3) after CERO surgery to lengthen the radius proximal to the ostectomy site by an amount equal to the degree of radial shortening (post-CERO). The joint space at 7 loci on dorsal plane and 6 loci on sagittal plane reconstructions was measured to assess changes in joint congruity between pre-op, post-ESF, and post-CERO. Repeated measures ANOVA with post hoc comparisons were performed to compare measurements between the 3 groups. RESULTS: Mean joint space measurements at most loci in the dorsal and sagittal planes were significantly different post-ESF compared with pre-op, confirming development of joint incongruency with the model. Post-CERO joint space measurements did not differ significantly compared with pre-op measurements, demonstrating the return to normal joint congruency using the CERO procedure. CONCLUSION: CERO surgery restored humeroradioulnar congruency in our cadaver model and may have application for acute correction of axial radial or ulnar incongruency in canine elbows secondary to elbow dysplasia or premature growth plate closure.