Norwich terriers possess a greater vertebral heart scale than the canine reference value.

Previous studies have demonstrated evidence that normal reference ranges for radiographic vertebral heart scale values can vary among dog breeds. The purpose of this retrospective, observational study was to determine whether the normal vertebral heart scale values published by Buchanan and Bücheler for lateral radiographs are applicable to the Norwich terrier. Secondary objectives were to determine if clinical signs of respiratory disease, age, sex, weight, body condition score, recumbency, or thoracic depth-to-width ratio had any influence on vertebral heart scale measurements in this breed. The electronic medical record systems of two universities were reviewed and Norwich terriers were included in the study if they had orthogonal thoracic radiographs performed and no historical or radiographic evidence of cardiopulmonary disease. A vertebral heart scale was calculated for each patient. Sixty-one client-owned, Norwich terrier dogs with no clinical signs of cardiovascular disease were evaluated. The vertebral heart scale for Norwich terriers without evidence of cardiac disease (10.6 ± 0.6) was found to be significantly greater than the canine reference value of 9.7 ± 0.5 initially established by Buchanan and Bücheler. No significant correlation was found between clinical signs of respiratory disease, sex, age, thoracic depth-to-width ratio or lateral recumbency, and vertebral heart scale. Norwich terriers with a body condition score ≥6 had a significantly higher vertebral heart scale than those with a body condition score ≤5. Breed-specific ranges and body condition scores need to be considered when interpreting vertebral heart scale values for Norwich terriers.

Anatomic characterization of the location of the esophageal ostium relative to the rima glottidis on CT in adult Labrador Retrievers.

OBJECTIVE: To characterize the anatomic location of the esophageal ostium relative to the rima glottidis in adult Labrador Retrievers with the use of CT. ANIMALS: 98 CT scans of 75 adult Labrador Retrievers. PROCEDURES: A search of the medical records database identified records of Labrador Retrievers that underwent CT of the head and neck between January 1, 2015, and December 31, 2018. Evaluators, blinded to each other's results, reviewed CT images and measured esophageal area at the level of the rima glottidis. For each dog, the left esophageal percentage (LEP) was calculated as the esophageal area left of the rima glottidis midline divided by the overall esophageal area at that level. Variables (age, sex, patient position, intubation status, and maxillary support during CT) were evaluated for association with LEP. The CT images of dogs that had multiple scans were assessed for within-patient variance. RESULTS: Mean LEP was 56.2 ± 18.1% for all dogs. Only right lateral recumbency was significantly associated with LEP, with a lower LEP for dogs positioned in right lateral recumbency (42.4 ± 12.7%), compared with left lateral (63.0 ± 7.4%) or sternal (57.3 ± 18.8%) recumbency. No association was detected between LEP and other variables assessed. Eleven dogs had multiple CT scans; within-patient variance for LEP was ± 26.6%. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that, although most dogs had an LEP > 50%, the esophageal ostium was fairly centrally located in most dogs and may be more mobile than previously thought. Additional research is warranted to assess this mobility and whether the esophageal ostium location, relative to the larynx, affects the incidence of aspiration pneumonia in dogs undergoing surgical treatment for geriatric-onset laryngeal paralysis and polyneuropathy.