CAL: radiology of cardiac diseases

Question 1

What faults show you look for before looking at the radiograph for signs of disease? 4

Answer 1

• Over/underexposure
• Movement blur
• Poor positioning
• Over/underinflation of the lungs

Question 2

What often happens if you radiograph cats without sedation?

Answer 2

thoracic limbs haven’t been extended cranially and there is quite marked rotation fo teh thorax.

Question 3

What misdiagnosis can underexposure of a thoracic radiograph lead to?

Answer 3

Overinterpretation of normal lung opacities as oedema.

Question 4

What might right lateral recumbency immediately prior to taking a thoracic radiograph led to ?

Answer 4

an apparent collapse of the right lung.

Question 5

What should you do if the thorax if thick enough to create enough scatter to adversely affect the quality of the film?

Answer 5

use a grid to limit the amount of scattered radiation that will reach the xray cassette. This usually occurs once the thorax is 10-13cm thick.

Question 6

What is the appearance of a thoracic radiograph with too much scatter?

Answer 6

fogging of the film which reduces radiographic contrast. This makes a radiograph seem excessively grey.

Question 7

What is radiographic exposure a combination of? 3

Answer 7

the energy of the beam (kVp), the number of x-ray photons per unit time (mA) and the duration of exposure (s)

Question 8

Is a low or high kVp good for thoracic radiography?

Answer 8

High kVp because it results in more shades of grey (this is good for the thorax as this already has much inherent contrast). You will see more structures in the lung (mainly BVs) using a high kVp.

Question 9

Is there much variation between cat and dog breeds in there hearts?

Answer 9

Cats - little variation between breeds

Dogs - much variation.

Question 10

What is the main cause of variation in hearts between cats?

Answer 10

Not breed but age. In older cats the long axis of the heart becomes progressively more horizontal, eventually becoming parallel to the sternum.

Question 11

What is the general appearance of hearts in deep-chested dog breeds (e.g. dobermans)?

Answer 11

narrow, upright, tall hearts

Question 12

What is the general appearance of hearts in barrel-chested dog breeds (e.g. springer spaniel)?

Answer 12

wide, globular, quite short hearts.

Question 13

T/F: cardiac disease which is severe always has radiographic signs of the cardiac abnormality

Answer 13

False - cardiac abnormality is not always present.

Question 14

What is suggested if the caudal border of the heart is still fairly curved?

Answer 14

that the LA is probably normal sized (bulge in the caudal cardiac border with LA enlargement)

Question 15

How do you identify an enlarged RV radiographically?

Answer 15

increased sternal contact
rounding of the cranial cardiac border (lateral view)
enlarged pulmonary artery
dilation of the caudal lobar arteries

Question 16

What are the Ddx for microcardia? 5

Answer 16

• shock
• blood loss
• hypoadrenocorticism (Addison’s)
• iatrogenic
• pulmonary emphysema

Question 17

What are radiographic signs of pericardial fluid/disease?

Answer 17

hard to differentiate (especially in cat) but is suggested by overall rounding of the margins and crispness of the cardiac silhouette. Echocardiography will be useful.

Question 18

CHF due to global cardiomyopathy will lead to what signs?

Answer 18

predominantly left sided cardiac failure signs

Question 19

CHF due to pericardial diseae will lead to what signs?

Answer 19

predominantly right sided heart failure signs

Question 20

List Ddx for generalised enlargement of the cardiac silhouette - 13

Answer 20

• genuine cardiac disease
• cardiomyopathy
• advanced mitral/tricuspid insufficiency
• physiological enlargement of the heart
• training or non-cardiac conditions
• bradycardia
• pericardial disease
• pericardial effusion
• PPDH
• other factors that mimic cardiomegaly
• expiratory radiograph
• pleural effusion
• excessive intrathoracic fat.