CXR interpretation

Question 1

PA/AP

Answer 1

Heart appears larger on AP

Other consideratiosn: Size of the heart, scapular edges, AP slightly lower quality as acquired with portable machines

Question 2

Underexposed
Overexposed

Answer 2

Underexposed - too white
Overexposed - too black

Question 3

Quality of position considerations

Answer 3

Check the clavicles
Is the distance equal both sides?
Is one shoulder rotated forward compared to the other?
Rotation impacts the ratios of the heart
Often unavoidable and is the normal posture of the patient.

Question 4

A-H approach

Answer 4

A. Airway
B. Bones and soft tissues
C. Cardiac
D. Diaphragms
E. Expansion
F. Fields and Fissures
Gadgets
H. Hidden areas

Question 5

Airway considerations

Answer 5

Is the airway deviated?

Question 6

Bones

Answer 6

Fractures
Dislocations
Rib crowding
Previous surgery
- plates
- pins
- cages

Question 7

Cardiac - normal

Answer 7

Outline is smooth

2/3 L; 1/3 R

Less than 50% of the diameter of the thoracic cavity (in a PA – will appear slightly larger on an AP)
Hilar – should appear smooth; L usually higher than the R or equal (L should never be lower than R).

Question 8

Cardiac problems noticed on x-ray

Answer 8

Cardiomegaly- enlarged heart

Pneumothorax - shifted heart

Silhouette sign - unclear heart border

Sail sign- wedge of collapsed tissue behind the heart border

Left LL collpase
Appears like a boat sail

Question 9

Diaphragms - normal

Answer 9

R usually higher than L due to liver

Costophrenic angles

Question 10

Hemidiaphragm

Answer 10

Occurs when one side of the diaphragm becomes weak from muscular disease or loss of innervation due to phrenic nerve injury

Question 11

Loss of clear costophrenic angles causes

Answer 11

Pleural effusion
Pleural thickening
Lung scarring
Atelectasis
Emphysema

Question 12

Expansion

Answer 12

Anterior aspect of at least 6 ribs should lie above the level of the dome of the hemidiaphragm in the mid-clavicular line.

And 10 ribs posteriorly.

Question 13

Fields and fissures

Answer 13

Looking at lung markings

Looking for areas that appear whiter (dense tissue/fluid) or darker (air) than you would expect

Equal density in left and right

Question 14

Fissure (horizontal)

Answer 14

In AP CXR, may be seen at the level of 4th rib anteriorly

Is there fluid in the fissure

Has the fissure moved - suggesting a collapse

Question 15

Gadgets

Answer 15

Pacemaker
ECG leads
Tracheostomy
NG tube
Chest drain
Sternal wires
Spinal fixation

Question 16

Common abnormalities

Answer 16

Patchy opacity
May affect: one side, lobe, a whole lung or both lungs.
Silhouette sign
Air bronchograms
All structures in expected position

Question 17

Atelectasis - collapse/loss of volume

Answer 17

• Uniform white appearance
• Can be localised to one lobe or a whole lung
• There may be rib crowding
• Evidence of reduced expansion
• Movement of structures towards the area that is more white

Question 18

Pleural effusion

Answer 18

‘blunting’ of the costophrenic angles

Uniform white appearance with a defined line and a meniscus

Uniform white appearance throughout a whole lung field with movement of structures away from this.

Blunting - approx. 200-300 ml

Question 19

Hidden areas

Answer 19

Lung apex, superimposed over the heart, around each hilum and below the diaphragm

Question 20

Pulmonary oedema

Answer 20

Bilateral increased lung markings.
Classically peri-hilar and shaped like bats wings.
Septal (Kerley B) lines
* At the costophrenic angle
* Horizontal lines reaching the lung edge
Effusions may also be present

Question 21

Bullae- common in COPD

Answer 21

Areas of lung that appear more black within/adjacent to areas with lung markings in.

These areas may have defined margins

Large bullae to both superior and mid zones.

Severe chronic emphysematous changes bilateral lung fields.

Increased air space opacification right mid and lower zones.

Question 22

3 cardinal features of pneumothorax

Answer 22

A clearly defined line is visible that parallels the chest wall.

The upper part of the line is curved at the apex.

There’s an absence of lung markings between the lung edge and the chest wall.

Question 23

Hilar

Answer 23

Could have increased density around the hilar

Bats wing pattern

Suggest pulmonary oedema/fluid overload/heart failure and increased blood flow to the area