RA |
12
A
|
MPA
LAu
|
A |
LA |
9 |
6 |
3 |
RAu |
9 |
12 |
3 |
||||
6 |
RV |
LV |
RV |
LV |
1 . Using a lateral thoracic radiograph , ensure the thoracic vertebrae T4 to T12 are clearly delineated .
2 . Using calipers , measure the longest axis of the cardiac silhouette from the carina of the mainstem bronchus to the apex ( designated “ L ”).
3 . Transfer this long axis measurement to the vertebrae , starting at the cranial edge of T4 , and count the number of vertebrae that fall within the caliper points .
4 . Using calipers , measure the short axis at the widest part of the cardiac silhouette , perpendicular to the long axis measurement ( designated “ W ”).
5 . Transfer this short axis measurement to the vertebrae , starting at the cranial edge of T4 , and count the number of vertebrae that fall within the caliper points .
6 . Sum the two measurements . VHS = W + L
|
L4
W
|
W |
L |
|||||
Considerable breed variation exists with the VHS . The suggested mean value for dogs was 9,7 ± 0,5 v ( range 8,5 - 10,5 v ). |
L |
|||||||
Breed specific normals have been established . Boxer - 11.6 ± 0.8 v Cavalier King Charles Spaniel - 10,6 ± 0,5 v German Shepherd Dog - 9,7 ± 0,7 v Labrador Retriever 10,8 ± 0,6 v Yorkshire Terriers - 9,7 ± 0,5 v . SOURCE : BSAVA Manual of Canine and Feline Thoracic Imaging . Eds : Toias Schwartz , Victoria Johnson , 2008 |
Compiled by Dr Liesel van der Merwe . Images courtesy Dr Lynelle Sweers |