Diagnostic imaging in CV radiology

Question 1

Radiographic signs of LEFT-sided HF - 2

Answer 1

pulmonary congestion - enlarged veins (lateral view). Enlarged arteries and veins (DV view) pulmonary oedema

Question 2

Radiographic signs of RIGHT-sided HF - 3

Answer 2

Hepatomegaly Peritoneal effusion Pleural effusion

Question 3

What does this show?

Answer 3

Enlarged veins - sign of pulmonary congestion - left sided HF

Question 4

What does this show?

Answer 4

Pulmonary oedema - sign of left-sided HF

Question 5

What does this show?

Answer 5

pulmonary oedema - cat - left sided HF

Question 6

What does this show?

Answer 6

Pleural fluid - cat - left sided HF

Question 7

Where does pulmonary oedema affect dogs?

Answer 7

Usually caudal lung lobes, if severe can spread throughout

Question 8

Where does pulmonary oedema affect cats?

Answer 8

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.

Question 9

What does radiographic assessment focus on in animals without overt cardiac failure? 2

Answer 9

Size and shape of the cardiac silhouette

Question 10

What features of radiographs may be subjectively used to assess cardiac size? 5

Answer 10

• 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.

Question 11

What does this show?

Answer 11

Normal heart size

Question 12

What does this show?

Answer 12

Hypovolaemia after biopsy

Question 13

What is the VHS?

Answer 13

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.

Question 14

What causes concentric hypertrophy?

Answer 14

Pressure load - e.g. aortic stenosis

Question 15

What causes eccentric hypertrophy?

Answer 15

Volume load - e.g. mitral insufficiency

Question 16

Are eccentric hypertrophy and dilatation the same?

Answer 16

No - see diagram

Question 17

What may increases in cardiac size reflect? 3

Answer 17

Cardiac dilatation Eccentric hypertrophy Pericardial effusion

Question 18

Outline canine variations in heart size

Answer 18

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!

Question 19

What might changes in cardiac shape reflect?

Answer 19

enlargement of specific chambers or vessels

Question 20

What might cause a round cardiac silhouette?

Answer 20

Pericardial effusion

Question 21

What affects the normal cardiac shape? 3

Answer 21

Inter-breed variations Individual variations Recumbency (difference between L and R. Left lateral recumbency can make the heart look a bit too round)

Question 22

Describe general cardiac shape in brachycephalics and some puppies

Answer 22

rounded silhouette

Question 23

Describe cardiac shape in retrievers

Answer 23

square, broad silhouette

Question 24

Describe cardiac shape in Dobermans

Answer 24

Upright, straight caudal border

Question 25

Describe cardiac shape in Setters and Afghans

Answer 25

Tall, slim cardiac silhouette

Question 26

What does this show?

Answer 26

Textbook example of normal cardiac shape - lateral view

Question 27

What does this show?

Answer 27

Textbook example of normal cardiac shape - DV view

Question 28

What does this show?

Answer 28

Enlarged LA

Question 29

What does this show?

Answer 29

enlarged LA

Question 30

What does this show?

Answer 30

Textbook example of dog with PDA in DV view

Question 31

What is radiology useful for? Not useful for?

Answer 31

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.