Diagnostic imaging in CV radiology Flashcards
Radiographic signs of LEFT-sided HF - 2
pulmonary congestion - enlarged veins (lateral view). Enlarged arteries and veins (DV view) pulmonary oedema
Radiographic signs of RIGHT-sided HF - 3
Hepatomegaly Peritoneal effusion Pleural effusion
What does this show?
Enlarged veins - sign of pulmonary congestion - left sided HF
What does this show?
Pulmonary oedema - sign of left-sided HF
What does this show?
pulmonary oedema - cat - left sided HF
What does this show?
Pleural fluid - cat - left sided HF
Where does pulmonary oedema affect dogs?
Usually caudal lung lobes, if severe can spread throughout
Where does pulmonary oedema affect cats?
Less predictable than in cats, occur in a variety of locations within lung, sometimes in a localised patch that mimics other aetiologies (e.g. bronchopneumonia). If in doubt, repeat thoracic radiographs after 12 hours of diuresis - oedema will be reduced or eliminated but other causes of infiltrate probably won’t change.
What does radiographic assessment focus on in animals without overt cardiac failure? 2
Size and shape of the cardiac silhouette
What features of radiographs may be subjectively used to assess cardiac size? 5
- Proportion of thoracic diamter occupied by the heart shadow. - Number of ICSs occupied by the heart shadow - Shape of the heart shadow - Position of the trachea - Distance between the heart and diaphragm.
What does this show?
Normal heart size
What does this show?
Hypovolaemia after biopsy
What is the VHS?
Vertebral Heart Scale Normal VHS = 8.7-10.7 Its use doesn’t increase the accuracy of radiographic diagnosis of cardiac disease since the normal range is imprecise and many cardiac diseases don’t increase external dimensions anyway.
What causes concentric hypertrophy?
Pressure load - e.g. aortic stenosis
What causes eccentric hypertrophy?
Volume load - e.g. mitral insufficiency
Are eccentric hypertrophy and dilatation the same?
No - see diagram
What may increases in cardiac size reflect? 3
Cardiac dilatation Eccentric hypertrophy Pericardial effusion
Outline canine variations in heart size
There are marked inter-breed and individual variations in cardiac size - puppies, brachycephalic breeds and fat dogs usually have a relatively large, rounded cardiac silhouette that is easily misinterpreted as diseased!
What might changes in cardiac shape reflect?
enlargement of specific chambers or vessels
What might cause a round cardiac silhouette?
Pericardial effusion
What affects the normal cardiac shape? 3
Inter-breed variations Individual variations Recumbency (difference between L and R. Left lateral recumbency can make the heart look a bit too round)
Describe general cardiac shape in brachycephalics and some puppies
rounded silhouette
Describe cardiac shape in retrievers
square, broad silhouette
Describe cardiac shape in Dobermans
Upright, straight caudal border
Describe cardiac shape in Setters and Afghans
Tall, slim cardiac silhouette
What does this show?
Textbook example of normal cardiac shape - lateral view
What does this show?
Textbook example of normal cardiac shape - DV view
What does this show?
Enlarged LA
What does this show?
enlarged LA
What does this show?
Textbook example of dog with PDA in DV view
What is radiology useful for? Not useful for?
Diagnosing HF (pulmonary oedema - dogs. Pleural fluid - cats). Other cardiac diagnoses are difficult - in most cases, measurements don’t help and shape is an unreliable guide to chamber enlargement.
