title: Vertebral scale system to measure heart size in thoracic radiographs of Indian Spitz, Labrador retriever and Mongrel dogs.
abstract: OBJECTIVE
  To establish reference values of vertebral heart score (VHS) in Indian Spitz, Labrador retriever, and Mongrel dogs; to assess applicability of VHS in these three dog breeds; to determine if breed, recumbency side, gender, body weight, and thoracic depth (TD) to thoracic width (TW) ratio has an influence on the VHS measurement in these dog breeds.
  
  
  METHODS
  A total of 60, client owned, clinically healthy Indian Spitz (n=20, mean age = 4.25±2.15 years, body weight = 11.87±2.7 kg), Labrador retriever (n=20, mean age = 4.75±1.91 years, body weight = 27.31±5.43 kg), and Mongrel dogs (n=20, mean age = 4.25±1.52 years, body weight = 16.25±3.99 kg), having no radiological and clinical signs of cardiovascular or pulmonary disease were included in the study. All dogs were restrained manually and left lateral (LL) and right lateral (RL) radiographic views were obtained. The size of heart in lateral radiographs was calculated using VHS method. Besides, the TD, TW and TD: TW were calculated to determine the type of thoracic conformation in the dog breeds. In addition to this, the effect of breed, side of recumbency, gender, body weight, and TD to TW ratio on the calculation of VHS was determined.
  
  
  RESULTS
  VHS was calculated in all the animals of the breeds. VHS in Spitz and Labrador retriever was significantly (p<0.0001, p<0.0001, respectively) >9.7±0.5 v. RL and LL VHS in Mongrel dog was significantly (p<0.037) >9.7±0.5 v. Significant (p<0.05) differences in the VHS were observed among Spitz, Labrador retriever and Mongrel dogs, being higher for Labrador retriever followed by Spitz and Mongrel dogs. VHS in RL recumbency was significantly (p<0.001) greater than VHS in LL recumbency in all three breeds. LL and RL VHS correlated significantly with each other in Spitz (r=0.58; p=0.02), Labrador retriever (r=0.87; p<0.0001), and Mongrel dogs (r=0.93; p<0.0001). Significant (p<0.05) differences in the TD and TW were observed among Spitz, Labrador retriever, and Mongrel dogs. Non-significant effect of gender, body weight, and TD to TW ratio on the VHS measurement was observed in each dog breed.
  
  
  CONCLUSIONS
  Breed-specific VHS reference ranges should be used for the objective measurement of heart size in dogs. Furthermore, the radiographic view should also be taken into consideration to avoid any erroneous interpretation of cardiac enlargement in dogs.
authors.affiliation: Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Deepti
authors.initials: D
authors.lastname: Bodh
authors.affiliation: Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Mozammel
authors.initials: M
authors.lastname: Hoque
authors.affiliation: Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Abhishek Chandra
authors.initials: AC
authors.lastname: Saxena
authors.affiliation: Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Mudasir Bashir
authors.initials: MB
authors.lastname: Gugjoo
authors.affiliation: Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Deepika
authors.initials: D
authors.lastname: Bist
authors.affiliation: Division of Livestock Economics, Statistics and Information Technology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: J K
authors.initials: JK
authors.lastname: Chaudhary
keywords: dogs; radiography; recumbency; thorax; vertebral heart scale