Thoracic Rads

Question 1

Increasing Radiographic Opacities

Answer 1

• Air
• Fat
• Soft tissue and Fluid
• Mineral (Bone)
• Metal

Question 2

What is contrast in radiology?

Answer 2

Differences in Photographic Densities in a radiograph

Question 3

How to Create a Thoracic Radiograph

Answer 3

• Pull forelimbs forward
• Want radiograph at maximum inspiration
  
  • Lateral= caudodorsal lung reaches T12
  • VD/DV = Cupula reaches T8-T10
• Indications for study will determine which views are necessary
  
  • area of interest?
  • Minimum 2 orthogonal views!! (at 90 degrees to each other

Question 4

Lateral views

Answer 4

• Named according to recumbency
• right lateral recumbency = RIGHT LATERAL
• left lateral recumbency = LEFT LATERAL

Question 5

Dorsoventral vs. Ventrodorsal view

Answer 5

• Named by the point of entry to point of exit of x-ray beam
• enters back and exits belly = DORSOVENTRAL
• enters belly and exits back = VENTRODORSAL

Question 6

How things look RIGHT LATERAL

Answer 6

• cardiac silhouette “egg shaped”
• diaphragmatic crura parallel to each other
• right crus more cranial
• Better for visualizing LEFT lung lobes

Question 7

How things look LEFT LATERAL

Answer 7

• cardiac silhouette is more rounded
• diaphragmatic crura diverge
• left crus more cranial
• Better for visualizing RIGHT lung lobes

Question 8

Why can you see the lung lobes better when the animal is lateral recumbent on the other side?

Answer 8

• Contrast (different opacities) allows visualization
• Dependent (down) lung is compressed (atelectasis) = looks more like a soft tissue opacity
• Non-dependent (up) lung is more aerated
• Better aeration = better contrast

Question 9

Dorsoventral view

Answer 9

• cardiac silhouette more consistent and round
• diaphragm has one dome (cupula)
• see caudal lobar vessels better

Question 10

Ventrodorsal view

Answer 10

• heart “flops” = cardiac silhouette may look elongated

- diaphragm had 3 domes (cupula and 2 crura) -> “Mickey Mouse”

Question 11

Standard viewing protocol for viewing radiographs

Answer 11

• Head to the left on lateral

- Left on the right in VD/DV

Question 12

Why is it important to view the radiographs in a consistent manner (standard viewing protocol)?

Answer 12

By looking at them in the same way each time, it cuts down on the info to process the radiograph
(already oriented, so can look for problems instead of needing to take time to figure where you are)

Question 13

Film Interpretation

Answer 13

• Extrathoracic structures = soft tissues, bones, abdomen
• thoracic wall
• diaphargm
• pleura/pleural space
• mediastinum = trachea, esophagus, lymph nodes, aorta, CVC
• heart and vessels = cardiac silhouette, lobar/ pulmonary vessels
• lungs

BE SYSTEMATIC!!

Question 14

interlobar fissures

Answer 14

areas where lung lobes are in contact with one another

normal = invisible or faint, thin line

Question 15

Cranial mediastinum

Answer 15

• trachea
• esophagus
• major vessels
• lymph nodes = sternal and mediastinal
• thymus in young animals (

Question 16

Middle Mediastinum

Answer 16

-cardiac silhouette
aortic arch
-esophagus
-lymph nodes = tracheobronchial
-terminal trachea

Question 17

Caudal mediastinum

Answer 17

• caudal vena cava
• descending aorta
• esophagus

Question 18

Lymph Nodes

Answer 18

• NOT seen in normal animals
• Need to know where they are in order to ID disease
• Sternal
• Cranial Mediastinal
• Tracheobronchial

Question 19

Heart and Vessels

Answer 19

• Cardiac silhouette
• can only see external margins of pericardium
• cannot see chamber size/thickness
• cannot determine condition of valves
• cannot see dynamic heart fucntion
• canine = sig. breed-related anatomic variation
• feline = more consistent; age related changes

Question 20

Lateral Projection: Heart (Cranial Border)

Answer 20

• right auricle
• ascending aortic arch
• main pulmonary artery
• right ventricle

Question 21

Lateral Projection: Heart (Caudal Border)

Answer 21

• left atrium

- left ventricle

Question 22

Clock Face Analogy - lateral view of heart

Answer 22

12: 00-2:00 = Left Atrium
2: 00-5:00 = Left Ventricle
5: 00-9:00 = Right Ventricle
9: 00-11:00 = Main Pulmonary Artery, Right Auricle, Aortic Arch

Question 23

VD/DV Clock Face

Answer 23

11: 00-1:00 = Aortic Arch
1: 00-2:00 = Main Pulmonary Artery
2: 00-3:00 = Left Auricle
3: 00-5:00 = Left Ventricle
5: 00-9:00 = Right Ventricle
9: 00-11:00 Right Atrium

Question 24

VD/DV Clock Face - Feline

Answer 24

2:00-3:00 = Left Atrium and auricle