2013/05/02

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Reading Chest X-rays

HS Schaaf

Desmond Tutu TB Centre, Department of Paediatrics and Child

Health, Stellenbosch University

Chest X-ray

• Most frequently performed radiographic investigation in children

• Important to read correctly as diagnosis and treatment is often based on this

• Technical errors may influence interpretation

• Normal variations do occur

• Supine antero-posterior (AP) projection used in infants

• Erect AP projection in toddler

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Basic Conditions • A good viewing box makes it easier (or

digital system)

• AP and lateral radiographs must be done

• All previous chest radiographs must be

looked at and compared to current one

• Use a systematic approach every time

you evaluate a chest radiograph (e.g. rule

of 3’s)

Artifacts

• Skin folds

• Incubators

• Hair plaited or dressed with ornaments

• Clothes with metal objects

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Systematic approach

• Identity (3)– Name

– Date

– Type of CXR (projection AP, PA, lateral; erect or supine)

• Quality (3)– Rotation

– Penetration

– Inspiration

Rotation

• The clavicle heads must be inline

• The anterior rib ends on each side should be equidistant from the lateral chest wall

• Lordotic view – when the clavicles are too low down in the lung fields – hilar areas lifted out from behind the heart shadow

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Penetration

• Should be able to see

• Vessels behind heart

• Pulmonary vessels 2/3 to periphery

• Trachea and proximal bronchi

• Correct penetration = being able to just distinguish the intervertebral spaces through the heart shadow

• Over-penetration : black lung fields

• Under-penetration : white – ‘airspace disease’

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VERTEBRAL BODY

INTERVERTEBRAL DISC

VESSELS BEHIND THE HEART

VESSELS 2/3 TO PERIPHERY

TRACHEA AND PROXIMAL BRONCHI

EXPOSURE FACTORS © Richard Pitcher 2003

Under penetration

Over penetration Normal

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Overpenetrated (High KV) airways only

Inspiration

• Adequate inspiration is when the 8-9th posterior rib is visible or 5-6th anterior rib (only count those you can see fully)

• Use only posterior ribs in younger children

• Hyperinflation– > 9 posterior ribs

• Poor inspiration– < 8 posterior ribs

• Unilateral hyperinflation ( Bal-valve effect )

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INSPIRATORY

EXCURSION

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© Richard Pitcher 2003

EFFECT

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1

Chest X-ray in expiration

1. Small lung volumes

2. Increases heart size

3. Airways difficult to see

Hyperinflation

Bilateral

• > 9 posterior ribs

• Reduced vascular markings

• Flat diaphragms

• Small heart

Unilateral

• > 9 posterior ribs

• Reduced vascular markings

• Flat hemi diaphragm

• Herniation of lung

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1. > 9 posterior ribs

2. Reduced vascular markings3. Flat diaphragms4. Small heart5. Bulging of lung

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3

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Severe

hyperinflation

Reading Lateral CXRs

• Penetration

• Inspiration

• Arms in poor position

• Rotation

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2

4

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5 7

Identify the diaphragms.-The right hemidiaphragm

(1) can be seen to stretch

across the whole thorax and

can be clearly seen passing

through the heart border

-The left (2) seems to

disappear when it reaches

the posterior border of the

heart

Compare the appearanceof the lung fields in front ofand above the heart tothose behind

-They should be of equal

density

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2

4

6

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Look carefully at the retrosternal space (4)

- Should be the blackest

part of the film

- An anterior

mediastinum mass will

obliterate this space

turning it white

Check the position of thehorizontal fissure (5)

- Faint white line

- Should pass

horizontally from the

midpoint of the hilum to

the anterior chest wall

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1

2

4

6

5 7

Check the position of the oblique fissure (6)

- Should pass obliquely

downwards from the

T4/T5 vertebrae

- Through the hilum

Ending at the anterior

third of the diaphragm

Check the density of the hila (7)

Conclusions

• Assess– Rotation

– Penetration

– Inspiration

• Practice reading AP and lateral

images

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Systematic approach

• White things (3)

– Mediastinum

– Heart shadow

– Bones / soft tissue (remember the spine in TB)

• Black things (3)

– Stomach bell

– Airways

– Lung fields

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Normal CXR

Intrathoracic TB features on CXR

• Lymph node disease– Perihilar– Paratracheal– Calcifications

• Airways compression

• Lobar opacification

• Ghon focus/complex

• Hyperinflation

• Lobar collapse

• Adult-type disease

• Fibrosis

• Perihilar infiltrates

• Miliary pattern

• Bronchopneumonicdisease

• Pleural disease

• Pneumothorax

• Tracheal deviation

• Mediastinal deviation

• Cardiac TB

• Spinal TB

• Diaphragmatic paralysis